Biodegradable Textiles, Recycling, and Sustainability Achievement

Abstract

Biodegradable textiles, Recycling and Sustainability Achievement

Full text

Biodegradable Textiles, Recycling, and
Sustainability Achievement
Reem Mohamed Nofal
Contents
Introduction . . . . . . . . . . ............................................................................. 3
Plastic Pollution and Environmental Hazards . . . . ................................................ 4
Biodegradation Process ........................................................................... 5
Definitions of Biodegradation ................................................................ 5
Biodegradation Conditions .................................................................... 7
Biodegradability of Fibers and Films in the Textile Field . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . 8
Wool....................... .................................................................... 9
Cotton ......................................................................................... 9
Flax Fibers ..................................................................................... 10
Hemp Fibers ................................................................................... 11
Jute Fibers ..................................................................................... 12
Ramie Fibers .................................................................................. 13
Kenaf Fibers ................................................................................... 13
Sisal Fibers .................................................................................... 14
Abaca Fibers .................................................................................. 14
Lyocell Fibers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. . .. .. .. .. . .. . . .. .. . .. .. .. . .. .. .. . . . .. 15
Other Biodegradable and Sustainable Fibers .................................................... 16
Poly(Lactic Acid) ............................................................................. 17
Polyacrylonitrile ............................................................................... 18
Biodegradability of Cellulose Fibers in Textile Blends .......................................... 19
Biodegradable Nonwovens and Their Applications ............................................. 21
Biodegradable Fibers in Geotextiles . . . .......................................................... 22
Enzymatic Hydrolysis During Biodegradability ................................................. 23
The Mechanisms of Enzymatic Reactions on Cellulose Fibers .............................. 23
The Mechanisms of Enzymatic Hydrolysis on Proteinic Fibers ............................. 25
R. M. Nofal (*)
Women’s college for Arts, Science, and Education- Ain Shams University, Cairo, Egypt
e-mail: reem.nofal@women.asu.edu.eg
© Springer Nature Switzerland AG 2022
G. A. M. Ali, A. S. H. Makhouf (eds.), Handbook of Biodegradable Materials,
https://doi.org/10.1007/978-3-030-83783-9_54-1
1

Evaluation of Textile Biodegradability . . . . ....................................................... 26
Enzymatic Hydrolysis . . . . . .................................................................... 27
Weight Loss ................................................................................... 28
Observation of a Surface Change ............................................................. 28
Changes in the Internal Structure ............................................................. 29
Tensile Properties (Breaking Load) ........................................................... 29
Textile Fibers and Fabrics Recycling Procedures . . . ......................................... 29
Sustainability in the Textile and Clothing Field ................................................. 30
Conclusions . . . . . . . ................................................................................ 32
Future Perspectives . . . . . . . . . . . . . . . . . . . . . . . .. .. .. . .. .. .. . . . .. .. .. . .. .. .. . .. .. .. . . . .. .. . .. .. .. . .. .. . 33
Cross-References ................................................................................. 33
References ........................................................................................ 33
Abstract
Tex tile fiber output has increased to about 100 million metric tons, with natural
fibers, synthetics, and other regenerated fibers being the most common types.
Because of the rising industrialization in the twentieth century, there was unprec-
edented growth in the emphasis on occupational safety. The result was broadened
in the difficulty of legislation, regulation, and environmental awareness in the
workplace. Biodegradable textiles refer to those fibers and/or fabrics decomposition
naturally using bacteria and fungi. Chemicals percentage used in the textile mate-
rials life cycle largely determines the textiles biodegradability. The more chemicals
used, the longer it takes for the fabric to biodegrade, causing environmental
destruction. Numerous biodegradable textiles are based on their degradability
degree, the time required to degrade completely, and ecological impact. This
chapter reviews a scientific description of the biodegradation means in textile fibers,
approaches, testing conditions, fibers biodegradation evaluation, the biodegrada-
tion mechanisms of several textile fibers, and their blends and composites, as well
as sustainability achievement philosophy in textiles and clothing fields.
Keywords
Biodegradation · Textile · Biodegradable fibers · Enzymes · Environment ·
Plastic pollution · Sustainability · Recycling
Abbreviations
AATCC American Association of Textile Chemists and Colorists
ASTM American Society for Testing and Materials
DMDHEU Low formaldehyde dimethylol dihydroxy ethylene urea
DMUG Dimethylurea glyoxal
DOP Degree of polymerization
FTIR Infrared Spectroscopy
MMT million metric tons
PBI Polyfunctional blocked isocyanate crosslinker
PLA Poly (lactic acid)
2 R. M. Nofal

SEM Scanning Electron Microscope
TOC Total organic carbon amount
XRD X-ray diffraction
Introduction
The term biodegradation is based on recycling natural wastes and impurities to
deteriorate natural matters into mixtures consumed as other organisms’nutrients.
Compounds decomposition is done by microorganisms like fungi, bacteria, insects,
worms, and many other tiny creatures. According to the biodegradation process,
nature can safely dispose of and recycle wastes and impurities and produce nutritious
compounds required for the new life growing of other organisms and the energy
needed for different biological progressions. Consequently, biodegradation is con-
sidered a vital process for the surrounding nature. The biodegradability process is the
critical process for daily used materials, and it is from the primary factors for
achieving sustainability [1].
Due to growing environmental pollution, it is required to introduce sustainable
design approaches, zero-waste strategy, product-life extra time, recovery of
resources, restoration, and reproduction services [2]. So the circular economy
agenda is formed by the 3R (diminish, recycle, reuse) philosophies that must be
used all over the cycle of production, consumption, and resource return, and the
circular model involves the engagement of all market participants [3,4]. Wearing
clothes for protection and aesthetic purposes is essential for a human. To achieve this
need, deliveries of textiles in fibers, fabrics, and products are manufactured daily
worldwide. Fiber production is expanding progressively. Figure 1shows the per-
centage of fiber world production per MMT from 1980 to 2025 [5].
Waste reduction during a product’s life cycle and the removal, or at least
minimization, of waste percentage ending up in landfills is considered one of the
critical challenges that the clothing and textile industry will face while the circular
160 Wool
Cotton
Cellulosic Fibres
Polypropylene
Fibre
Acrylic Fibre
Polyamide Fibre
Polyester Fibre
Million Metric Tons
140
120
100
80
60
40
20
0
1980 1985 1990 1995 2000 2005 2010 2015 2020 2025
Fig. 1 World fiber production 1980–2025. (Source: Tecon OrbiChem, copied from [2])
Biodegradable Textiles, Recycling, and Sustainability Achievement 3

economy transitions. Its success depends on producing a new approach to designing,
producing, and using up products. As a result of environmental legislation, there is a
growing need to use biodegradable materials and textiles [6,7]. The textile and
garments fiber consumption in the 2002 year was about 30 MT tons, as shown in
Table 1.
Plastic Pollution and Environmental Hazards
Chemists developed the artificial polymers called “plastics”during the twentieth
century. The first name (Bakelite) was produced by a Belgian chemist named Leo
Baekeland in 1907. The term “plastic”returns to moldable substances as the
manufacturing way. This industry appears in the 1930s. Polyethylene and then
nylon were invented. In 1937, commercial production of polystyrene started followed
by nylon. Development of numerous new plastics began during the Second World
War. But the significant development and extensive plastics usage in everyday house-
hold goods were detected in the 1950s. Plastics are cheap to manufacture and highly
durable. Plastic is widely used in food containers and packaging in the modern world.
Indeed, packaging represents the largest market sector for plastics [9].
More than 300 million tons of plastic produced every year are introduced to our
daily lives, half of which are single-use items such as plates, shopping bags, cups,
and straws. Consequently, at the end of each year, at least eight million tons of plastic
remain in our oceans. Floating plastic fragments are the most observable type of
marine litter right now. Discarded plastic accounts for 80% of all marine waste and
sediments from upper waters to deep-sea [10,11].
Synthetic polymers, opposite to natural organic materials in plastics, may con-
tinue unaltered and durable. Since the 1950th years in the environment, Plastics’
existence has made the presence of plastic in the remaining state certain of entrants
for the creation of the Anthropocene started. When plastic materials reach ocean
water, their decomposition is slower than on land. This is attributable to plastic
materials are not subjected to thermal oxidation in ocean water as on land; wastes
composed of plastics break down in aquatic environments at a slower rate than on
land. Plastic wastes and debris in ocean water are subjected to physical abrasion,
which causes the plastic breakdown process. Ultimately plastic remains with large
masses are scraped into smaller pieces [12].
Table 1 Apparel mill
consumption by fiber type
2002. (Adapted with
permission from Ref. [8].
Woodhead Publishing
2005)
Fiber type Million tonnes %
Cotton 13.0 43
Wool 1.3 4
Polyester 10.2 34
Acrylic 2.0 7
Cellulosic 1.8 6
Nylon 1.2 4
Others 0.5 2
Total 30.0 100
4 R. M. Nofal

Plastics are polymers that are carbon-based with repeated long-chain molecules.
Due to the synthetic structure of plastics, increasingly discarding plastic materials
harm the environment. The resulting pollution can be visually, physically, or by
accretion in nature, with harmful impacts on people’s habitations.
There have been increasing concerns about the impacts of plastic usage on
surrounding nature. Growing demands call for eco-friendly alternatives or solutions
and alternatives with reduced environmental impacts. Responses are increasing, and
methods have become further extensively affordable and available.
Ellen-Mac-Arthur Foundation (2016) stated that the whole weight of plastic
remains in oceans will be equivalent to the aquatic fish’s total weight by 2050.
Entanglement of plastic remains and swallowing them kills many marine creatures
yearly, such as macroscopical birds, marine turtles, and mammals to tiny zooplank-
ton, which use microplastic globules for feeding. The plastic remains accumulation
has a direct negative effect on marine ecologies. Persistent organic pollutants are
poisoning marine life due to the presence of microbeads and nurdles plastic frag-
ments. The resultant toxic materials are biologically accumulated in animal tissues
due to consuming plastics [13].
The ocean’sfiltering process from plastic debris is complicated to perform this
excellent task. Plastic remains are too broadly distributed and complicated. Water
channels and near-shore environments are usually cleared and filtered by individual
efforts to clear off such deadly fragments as deep-rooted nets of fishing and lines.
Yearly the beaches of the world receive various tons of plastic waste and remain.
Ocean Conservancy and others organize volunteer groups that supported efforts in
cleaning beaches. The vital efforts in plastic elimination from the ocean’s water are
to decrease the plastic debris percentages that reach the oceans. Plastic packaging
recycling and reducing plastic carrier bags usage significantly reduce plastic leftover
in the oceans. The elaboration of plastics with biodegradability properties would
help solve the problem [6,14,15].
Biodegradation Process
Definitions of Biodegradation
Substance conversion into new complexes over biological, chemical reactions, or
microorganism’s actions, such as fungi and/or bacteria. A process of alteration or
transformation of the structure of chemicals presented into the environment by the
action of the microbial organism (through enzymatic or metabolic action) [16].
Disintegration of a substance by enzymatic catalyzing actions in vivo or in vitro.
For hazard assessment, this can be expressed in the following categories:
Primary: Substance chemical structure alteration resulting in substance removal of a
definite property.
Environmentally acceptable: The biodegrading process to the extent of elimination
of specific unacceptable compounds properties. This process is similar to the
Biodegradable Textiles, Recycling, and Sustainability Achievement 5

primary biodegradation approach, and it depends on the environmental
conditions.
Ultimate is full compound decomposition or breakdown into simple molecules fully
reduced or oxidized (such as CO
2
/methane, nitrate/NH
4
+
, and H
2
O). Further-
more, the biodegradation outputs can be harmful to the degraded primary
substances [17].
A catalyzed reduction biological process in chemical complexity occured. The
biodegradation process of organic compounds frequently causes the conversion of
many of oxygen, carbon, nitrogen, phosphorus, sulfur components in the primary
molecules to the inorganic products [18]. Biodegradation is a technique causing
chemical composition change and pollutant substances structure produced by bio-
logical activities, leading to naturally occurring metabolite end products [19]
(Fig. 2).
When burying textile substrates in soil, the resident microorganisms participate in
their decomposition process, defined as biodegradation. Biodegradability is fre-
quently expressed as a standard assessment of the textile materials behavior as
eco-friendly to the environment or not. The textile’s biodegradability is likely to
be influenced by parameters such as the orientation percentage, crystallinity, the
extent of polymerization, hydrophobicity/hydrophilicity of textile, and the condition
of used soils in burying and of microorganisms types [20].
The polymer’s biodegradability has a high rate in lower molecular weight, lower
crystallinity or orientation, and higher hydrophilicity. Tiny organisms like fungi and
bacteria process biodegradation primarily by hydrolysis and/or oxidation reactions.
Fig. 2 Biodegradation schematic diagram of the biodegradable textile substrate
6 R. M. Nofal

Biodegradation Conditions
The biodegradation process occurred under different conditions.
Aerobic Biodegradation
In aerobic biodegradation, microorganisms convert oxygen to H
2
O to convert other
components into simpler products, or the process of decomposing organic matter in
the existence of oxygen is called aerobic respiration. In aerobic respiration, microbes
consume oxygen to oxidize a portion of the carbon in the pollutant (CO
2
), and the
remaining carbon forms a new cell. In biodegradation, the O
2
is exposed to reduc-
tion, and water molecules are produced. Therefore, the aerobic process’s main
byproducts are CO
2
,H
2
O, and increasing residents of bacteria, fungi, and other
microorganisms.
Anaerobic Biodegradation
It is the practice of decomposing compounds by the action of microorganisms in
oxygen absence. Anaerobic respiration is when bacteria and fungi use the acceptor of
an electron other than O
2
as a chemical entitle. Common oxygen substitutes are NO
-3
,
SO
4
2
, and iron. In anaerobic respiration, sulfate, nitrate, metals such as iron (Fe
3+
)and
manganese (Mn
4+
), or even CO
2
substitute oxygen, accepting electrons obtained from
the pollutant degradation. Accordingly, respiration of the anaerobic type uses inor-
ganic materials as acceptors to electrons. As well to new cell material, anaerobic
byproduct respiration possibly will incorporate nitrogen gas (N
2
), hydrogen sulfide
(H
2
S), metals form that are reduced, and (CH
4
), dependent on the acceptor of electrons
[17,21](Fig.3).
Organic material (polymeric chains)
AEROBIC AND ANAEROBIC BIODEGRADATION
Aerobic biodegration (+ O2)
Anaerobic biodegradation (-O2)
Microorganisms
CO2 + CH4
CO2 + H2O
+
+
Biomass
Fig. 3 Aerobic and anaerobic biodegradation schematic representation. (Adapted with permission
from Ref. [22]. Copyright 2014, Springer Science Business Media Singapore)
Biodegradable Textiles, Recycling, and Sustainability Achievement 7

Biodegradability of Fibers and Films in the Textile Field
Fibers are the raw materials that can be converted into yarns and are used in textile
and fabric manufacturing processes. Textiles can be classified into nature fibers (e.g.,
cotton as a plant source, wool as the animal origin, and mineral source asbestos) and
synthetic fibers, which are divided into chemical processes that use cellulose which
is a natural polymer and other processes of manufacture based on synthetic polymers
manufactured from petro-chemicals first generation (propylene, benzene, ethylene,
and xylene) [23,24].
The life standard is being higher; in all fields, the people’s demand is increasing,
besides the demands regarding new generations of textiles with upgraded properties
useful in the required industrial uses or higher comfort. Growing environmental
requirements to develop innovative fibers are urgently demanded recently, and
refusing classical synthetic fibers that are petroleum-based considered unfriendly
to the environment, as the rarity of petroleum is the primary resource material to
synthetic fibers. Traditional artificial fibers, for example, polyester, polyacrylic,
polypropylene, etc., are harmful to the environment. The main disadvantage of
synthetic polymers is nonrenewability and nondegradability. As synthetic fibers
Natural fibers
Animal fibers
Asbestos
Mineral fibers
Plant fibers
Hair
Silk
(tussah silk
mulberry silk)
Wool
(sheep)
Angora
(rabbit)
Mohair, Cashmere
(goat)
alpaca
Bast
Leaf
Stem
(jute, flax)
(sisal, manilla)
(whear, rice)
(coconut)
(cotton)
(wood)
Fruit
Seed
Other
Fig. 4 Classification of natural fibers. (Adapted with permission from Ref. [25], Copyright, 2011
Elsevier)
8 R. M. Nofal

are originated, their use has increased oil consumption meaningly and continues
currently. It was shown that the most commonly used among all fibers now is
polyester. Petroleum and oil are nonsustainable (nonrenewable) resources, and at
the current consumption rate, these consumed fuels will last for another 50 years,
nearly as expected; the consumption of petroleum is determined to be 100.000 times
higher than the natural generation rate [8] (Fig. 4).
Wool
The primary composition of animal fibers is amino acids units forming proteins; the
most famous proteinic threads are silk, wool, camel, alpaca and llama, vicuña, and
goat hair (known as mohair), horse, sable, rabbit, hog, beaver, badger, and other
animals. Wool is composed of follicles which are specific skin cells, in the Caprinae
family of animals, mainly sheep. Nevertheless, certain classes of other mammal’s
hair, such as llamas, rabbits, and goats, could also be termed wool. Different qualities
of wool have distinguished it from fur or hair: its crimp property, its unique,
additional handle or texture, its elasticity, and limited length as it is stapled fiber.
Wool is composed of different percentages of keratin, dirt, suint (as sodium,
potassium, salts of fatty acids), wool fats, and mineral impurities. Keratin consists of
units called amino acids, more than 20 different types. Wool fiber morphology
consists of the cuticle outer layer, cortex, and medulla inner layer. Wool fabric has
a unique property as an insulating medium, preventing transmission of body heat and
giving a feeling of warmth to the wearer. A further property in comfort is that wool
can absorb additional moisture without feeling clammy and cold as cotton does in
similar circumstances [26].
Cotton
The most commonly used fiber is cotton (Gossypium spp.), owing to its low cost and
unique comfort properties. Cotton seeds are the primary source of cotton fiber. Fibers
are fabricated of the seed’s hairs of cotton plant bolls. When cotton mature fruit
bursts, it gives a bunch of fibers with average length from 24 to 60 mm and average
cross-section diameters between 11 and 46 μm. Cotton fibers are distinguished by
their tri-wall construction. The layer named cuticle comprises waxes and pectins.
The outer layer is wax which shields the cuticle, consisting of crystalline fibrils
called cellulose. The fiber’s second wall consists of tri-diverse layers consisting of
parallel fibrils closely packed with a coiled winding range of 25–30, and it contains
the highest percentage of cellulose. The third wall encloses the lumen. The cross-
section morphology of cotton fibers is bean shape; however, the swelling process
makes its cross-section just about rounded when absorbing moisture. Cotton fibers
are composed of 80–90% cellulose, and a minor percentage remnant is represented
in fats and waxes, water, proteins, pectins and hemicelluloses, and ash [27,28].
Biodegradable Textiles, Recycling, and Sustainability Achievement 9

Cotton fibers swell significantly in water because they are hydrophilic. Fibers are
water stable, and their tenacity in wet conditions is reached 20% more than their dry
tenacity (25–40 cN/tex). Cotton fibers have a lower initial modulus and toughness
than hemp fibers, but they have a higher elongation at break (5–10%) and elastic
recovery. The fibers are alkali resistant on the contrary sensitive and degrading by
acids. Cotton fibers have low microbial resistance, burn quickly and easily, can be
sterilized by boiling, and cause no irritation or other skin allergies [27,29].
Bast fibers, also identified as stem fibers, are derivatives from the stalks or stems
of dicotyledonous plants (with twine seed leaves). They are grown in different
conditions as temperate (e.g., flax, hemp, and nettles), jute in subtropical conditions,
and kenaf planted in tropical climates. They have usually been termed soft an
inaccurate term concerning the fiber bundles’mechanical properties, distinguishing
them from hard leaf fibers.
Flax Fibers
Flax fiber is under the class of bast fiber and is the plant origin of (Linum
usitatissimum L.) the flax plant or linseed. It was stated that ancient Egyptians
used mainly linen to produce clothing, shrouds, and bed linen for ships and
mummies canvases in those times, and the old kingdom refers to it as the earliest
Egyptian linen cloth. Flax fiber is famous in the textile industry as linen [30].
Flax was the first plant fiber probably to be used by man for producing textiles, at
least in the Western world. Flax samples have been found in the Ancient Egypt
tombs and Switzerland, the prehistoric lake dwellings. Flax fiber originated from the
trunk of the yearly plant Linum usitatissimum, which grows in different subtropical
regions and temperate of the world. There are long, thick-walled cells in the central
bark of flax fiber, slender of which the fiber strands are consisted [31]. Flax fiber is
obtained from the stem skin or the bast of the flax plant. Flax fibers are organized in
thin longitudinal filaments arranged in slim bundles scattered around a central
Fig. 5 Cross-section of flax stem showing distinct fiber bundles (left), x10 showing the relative
position of fiber bundles in the stem (right), Source: Institut Technique du Lin, Paris. (Adapted with
permission from Ref. [33]. Copyright, 2005 Woodhead Publishing Limited)
10 R. M. Nofal

wooden tube shape. These bundles are completely fixed into an intermediate holding
tissue holding them externally to the protective outer skin and internally to the inside
supporting wooden barrel shape, as shown in Fig. 5. The holding tissue comprises
wholly dynamic cells; their membranes are semi-permeable. The wooden cylinder,
the fibers, and the outer skin, in contrast, are made up of stable standing cells; their
membranes are normally permeable [32].
Cellulose is the primary constituent of flax fibers and small percentages of
hemicellulose, pectins, lignin, oils, and waxes. The fiber cell walls consist of
cellulose, hemicellulose, and pectins [33]. Cotton and flax are both cellulosic fibers
and are nearly identical in chemical structure. Although the two fibers have quite
different tensile properties, a fiber tenacity of flax is reach to 6.3 gpd and in cotton
fibers with 3–5 grams per denier. Ramie and flax have high tensile strengths because
the fiber axis is composed of highly oriented molecules [34].
The primary physical characteristics of flax that differentiate it from other fibers
are as follows: moisture absorption and desorption are rapid, the cellulosic constit-
uent of the high fiber crystallinity, resulting in linen fabrics with high credibility, flax
yarns of low extensibility, flax fibers, and yarns characterized by high tenacity,
abrasion resistance of linen fabrics is relatively poor, linen fabrics characterized by
high luster, especially those produced from wet spun yarns, linen fabrics drapability
is aesthetically attractive [33].
Flax fabrics are characterized by highly absorbing moisture like perspiration,
providing comfort and coolness in humid climates to the wearer of flax fabrics. The
distinct property of linen fiber under wet conditions is that it swells and improves in
strength, and this is why spinning of flax is usually ideal under wet conditions more
than dry [30].
Flax fabrics production has economic characteristics as availability with fiber
bulks, continual novel production chain (as on the market new variations attain
yearly), elementary linen fibers length, and their physical properties are. These final
distinctive properties could be clarified by their long filaments with the slender shape
of the fiber (relative length to diameter ratio) and structural function. The flax
material resistance to bending and loading is due to fiber bundles being distributed
and organized outside the stem [35].
Hemp Fibers
Hemp is probably of the strongest natural bast fibers, which are considered from the
species of Cannabis of the hemp plant. Currently, hemp fibers have a wide accep-
tance in composite materials as reinforcements due to their being biodegradable
fibers and when compared with artificial fibers, it has low density. These materials
also have intrinsic mechanical, thermal, and acoustic properties [36].
Accordingly, hemp fiber is increasingly used in the composites industry as rein-
forcement due to its high specific strength relative to low density, it is eco-friendly and
biodegradable fiber, and it has a low cost of production. The biodegradability property
Biodegradable Textiles, Recycling, and Sustainability Achievement 11

of hemp fibers has become a progressively appealing aspect in selling products as
companies aim to be easily recyclable and ecofriendly [37].
Cellulose is the principal constituent of hemp fiber; its percentage reaches about
77% total weight of the fiber. Lignin, pectins, different substances soluble in water,
vegetable waxes, fats, and about 10% of hygroscopic water are the remainder
constituents. The constituent cellulose in hemp is lower than flax, although hemp
is more lignified and has less chemical sensitivity. It is alkalis resistant and would be
damaged by only strong acids. Subjecting to rotting is less in hemp than flax [38].
The hemp stalks are composed of several layers within fiber bundles. A bundle
contains several fibers and unit cells connecting bundles. The inner layers of the
bundles are generally finer and shorter than the external layers. The shape of the unit
cells is different from hexagonal to triangular with a large pith and curved corners.
Lignified pectins connect the cells, and hemp fibers’basic processing depends on
dissolving and loosening this bond. The unit cells’approximate diameter is from
15 to 50 μ. The length of cells is about 3.5 4 cm, and it can vary from 0.5 to 10 cm.
The fiber bundle’s length is about 1500 2500 mm. The breaking strength of hemp
is more than flax fiber. Hemp fiber is characterized by low elongation. The fineness
range of fiber bundles determines their flexibility. Bundles need less twisting during
the spinning process, especially long ones. While bundles elongation is relatively
low, hemp fibers have high flexibility causing conflicts during spinning [38].
Jute Fibers
Jute species called Corchorus capsularis appear in the shape of bundles under a
microscope with a yellowish cast. The final shape is polygonal but pointed with
lumina of medium size. Its counterclockwise twist has a distinct shape, which can
help distinguish it easily from flax. The dislocations show as angular X’sorY’s and
might be diverse. Jute products are cordage, mats, and heavy-duty cloth [39]. Jute is
an environmentally friendly natural product as it is biodegradable fiber. Generally,
jute does not cause pollution to the environment either during agricultural cultiva-
tion, manufacturing, transportation, and as end products or in the final disposal
period. Sacks and bags made of hemp are recyclable and reusable, so jute fibers
and fabrics are considered environmentally friendly and cheaper than disposable
packaging [38,40].
Jute comes after cotton, then flax and hemp in production popularity of plant
fibers, also the constituent lignin percentage is higher than other plant fibers as hemp
and flax. Countries with hot and humid climates such as India, Bangladesh,
Thailand, and China are suitable for jute growing. During jute agriculture in
4–6 months, its height reaches 2.5–3 m. The region called Bengal Delta is the
most famous for high-quality jute production. The specific time of harvesting jute
determines a vital property in quality which is tenacity. When the jute crop is in a
pod, the harvesting process begins. The jute bundles are separated from the stem
under slow running water by the retting process. The noncellulosic and interlamellar
materials rich in pectins are decomposed by microorganism-secreted enzymes [41].
12 R. M. Nofal

Jute has three primary chemical constituents: alpha-cellulose, lignin, and hemi-
cellulose [27]. Besides the main constituents, fiber contains different negligible
ratios about 2% of the total composition of materials such as waxes and fats,
nitrogenous matter, inorganic matter, and pigments. Jute has several properties that
are considered desirable; it has a natural and raw look, high tear and breaking
strength, good luster and sheen, a unique texture and bulk, inelasticity and dimen-
sional stability, and thermal insulation [38].
Ramie Fibers
The family of Urticaceae with the genus of Boehmeria is ramie fiber (Boehmeria
nivea). It is a widely used bast fiber and its cross-section is of about 25–75 μm[42].
Thick walls and flat cross-sections characterize ramie fibers. The fibers have short
and frequent dislocations and long crosswise striations. In the ramie morphology
cross-section view, radial cracks may appear. Ramie has a wide range of sacking,
ropes, and some clothing products [39].
Kenaf Fibers
Hibiscus cannabinus is the primary source of producing kenaf fibers. Kenaf is in two
types of fibers: short fibers and long fibers in the ligneous zone bundles and the
cortical layer. Elementary fibers are relatively short, with a mean diameter of 21 m
and a length ranging from 3 to 7 mm. Fiber cross-section is rounded triangular, and
lumens are typically bulky with rounded to oval shape [43] (Fig. 6).
The lumen thickness fluctuates substantially along the length of the cell and is
interrupted multiple times. Kenaf fiber contains about 45–57% of cellulose, 21.5%
hemicelluloses, 3–5% pectin, and 8–13% lignin. Fibers are characterized by brittle,
rough, and problematic in processing. Kenaf and low-quality jute fibers have the
same breaking strength and slightly weaken when wet. Kenaf fibers are great for
Fig. 6 Cross-section SEM
images of Kenaf fiber.
(Adapted with permission
from Ref. [44], 2018 Elsevier)
Biodegradable Textiles, Recycling, and Sustainability Achievement 13

whole stem and surface fibers, such as textiles, paper products, composites, absor-
bents, building materials, etc. [45].
Sisal Fibers
Sisal fibers are well known as a hard fibers obtained from fresh leaves of the sisal
plant called Agave sisalana. The decortication process is to get sisal fibers, in which
the leaves are passed and crushed between rollers and then mechanically abraded.
The average length of the sisal fibers is about 0.6–1.5 m and from 100 to 300 μm
cross-section diameter [45]. The constituent cellulose percentage is ranged from
about 70%. The fiber stem is made up of many long fiber cells with pointed corners
shape. Lamellae link fiber cells in the middle, consisting of ingredients such as
hemicelluloses, pectin, and lignin. The cross-section morphology of sisal consists of
nearly 100 fiber cells. Sisal fibers have a cross-section that is neither round nor
homogeneous in size. The lumen is usually highly defined and of different sizes. The
longitudinal morphology shape is cylindrical. The first, thick second, third wall, and
lumen are the four main components of each fiber cell. The fibrils are composed of
microfibrils whose thickness is about 20 micrometers. Microfibrils consist of cellu-
lose chains 0.7 m thick and a few meters long [46]. Sisal fiber is a stiff and coarse
fiber. It has varying tensile characteristics over its length.
The modulus and tensile strength of fibers derived from the lower regions of the
leaf are low. At the midpoint of the span, the fibers become stronger and stiffer, while
the fibers removed from the tip have moderate qualities. Due to its high cellulose and
hemicelluloses, the paper industry processes the fibers with low-quality grades. The
cordage industry uses medium-quality grades to make ropes, balers, and binder
twine. After treatment, the higher quality fibers are spun into yarns and used in the
carpet business [47].
Abaca Fibers
Manila hemp or Abaca fibers are extracted from the Musa textilis leaf section that
wraps around the stem (the abaca plant). Strands of commercial fibers are used, and
strands consist of a group of bundles of individual fibers. Individual fibers are
uniform and smooth in diameter when separate from the strands, and the lumens
are significant compared to the thickness of the walls. Cross-marking is uncommon,
and fiber tips are usually flat and ribbon-like. The technical fibers range in length
from 2 to 4 m. The single fibers have narrow pointed ends and are quite smooth and
straight. The diameters of individual fibers are about 14–50 m, with an average
length of about 2.5–13 mm [43].
Abaca commercial fiber is in the shape of strands containing numerous individual
fibers connected by natural gums. The strand length differs significantly depending
on the specific source and the treatment during the processing of the fiber. High-
grades abaca fiber is often in the shape of strands up to 4.5 m (IS ft) long. Abaca has a
good natural luster. Fiber color depends upon the processing conditions; the abaca
14 R. M. Nofal

color is off-white, and some poor-quality fiber grades are nearly black. Abaca is
adequately flexible and strong to provide a degree of giving when used in rope. The
fiber properties are not readily affected by saltwater. It has slight natural acidity,
which causes corrosion when abaca is used in wire ropes as a core. Individual fiber
cells are smooth-surfaced and cylindrical. The fiber’s average length is about
1/4 inch, which is regular in width. The ends gradually taper to a point. The fibers
are polygonal in cross-section, and the cell walls are thin. The lumen is prominent
and conspicuous; it is circular and uniform in diameter, despite periodic constrictions
in both the fiber and the lumen. Granular bodies can be found in the lumen
occasionally [29]. Abaca fiber, a biodegradable, eco-friendly, renewable, sustain-
able, and natural fiber alternative for textile designs, has gained popularity due to its
environmental features and excellent everyday performance during usage. Fibers are
natural, renewable, biodegradable, and sustainable textile supplies [48].
Lyocell Fibers
Another type of regenerated cellulose fiber made from wood pulp is lyocell fiber
(also known as Tencel in the United States) [49]. Among the significant discoveries
in cellulosic artificial fibers was Courtaulds’release of lyocell in 1995. Wood pulps
are liquified in a solution of amine oxide to create lyocell. The cellulose’s viscous
solution is extruded into amine oxide solution (dilute), so the cellulose is precipitated
and forms the lyocell fiber. Lyocell has a superior tensile strength property in dry
conditions than other synthetic cellulosic fibers, and it is considerably higher when
wet. This fiber has excellent chemical, physical, and mechanical properties to
viscose fiber, and the lyocell processing is also a particularly environmentally
method because it uses NMMO solvent that is nontoxic [43].
Lyocell fibers have different structural and physical properties than viscose fibers.
Higher strength, a higher degree of crystallinity, and a reduced elongation and
molecular orientation distinguish them [44,50]. Lyocell fibers merge the advantages
of viscose fibers (water resistance, comfort, and biodegradability) with the desired
Fig. 7 Biodegradability of lyocell fibers after soil burial periods, (a) untreated lyocell, (b) 4 days
soil burial, and (c) 7 days soil burial. (Adapted with permission from Ref. [53], copyright,
Woodhead Publishing, 2005)
Biodegradable Textiles, Recycling, and Sustainability Achievement 15

properties of polyester fibers (high strength). Lyocell fibers are primarily employed
in the production of garment fabrics, particularly outerwear. Due to their fibrillation
tendency, they can produce filters, nonwoven, and specific papers in the technology
industry [51,52]. Lyocell fiber has a circular to close cross-section form, and its
lengthwise morphology is cylindrical and very smooth without any striation [49].
Lyocell is a biodegradable fiber that, by the action of living organisms secreted by
enzymes, the fiber is broken down into water and carbon dioxide. Cellulosic fibers
are famous for their biodegradability properties versus synthetic fibers. Several
procedures assess the biodegradation process as soil burial tests (Fig. 7). It was
found that lyocell fibers entirely degraded after 42 days in a static aerated compost
pile and wholly degraded within a week in sewage farm anaerobic digester, wherever
the residence cycle is about 3 weeks. Soil burial tests (BS 6085/AATCC 30) are an
acceptable procedure for determining the biodegradability rate of a product, and
lyocell degrades entirely within 84 days [53]. Fibers of lyocell have a lower envier
and achieve sustainability on mental impact than synthetic fibers oil-derivatives
(e.g., nylon, polyester, acrylic) or natural fibers like cotton because they require
less land, pesticides, irrigation. So the forests should be managed in a sustainable
manner and fertilizers in cultivating the eucalyptus plants or trees in beeches from
which Lyocell fibers are extracted [30].
Other Biodegradable and Sustainable Fibers
Park et al. [18] studied the natural fibers biodegradability, such as cotton and flax,
and reproduced cellulosic fibers as cellulose acetate, viscose, and rayon. Cotton and
flax fibers are characterized by relatively high orientation and crystallinity, and also,
they are hydrophilic. In contrast, regenerated cellulosic fibers such as viscose rayon
and cellulose acetate have further amorphous and less crystalline content. Viscose
rayon is the most hydrophilic natural cellulosic fiber, whereas regenerated cellulose
acetate hydrophilicity is low due to acetyl groups (–COCH3) substitution for some
(-OH) groups in the molecules. Cotton, flax, cellulose acetate, and viscose rayon
fibers are all. Cellulose’s main constituent material differs in chemical compositions,
crystallinity percentage, DOP, and manufacturing processes.
Furthermore, the noncellulose content and composition of each fibrous substance
vary. The biodegradability is assessed by three methods: soil burial test, enzyme
hydrolysis, and activated sewage sludge test, and the rate was uppermost in viscose
rayon, then cotton and cellulose acetate, respectively. Flax fibers displayed fickle
performance. Achieving the highest biodegradability rate in soil burial test, it
oppositely biodegradability rate lower than viscose rayon and cotton in activated
sewage sludge test and enzyme hydrolysis [54] (Fig. 8).
It was noticed that colonization of the microorganisms appeared in the viscose
fiber after 4 months of soil burial test. The remarkable changes in fabrics of cellulosic
content are due to the high hydrophilicity. Amorphous character, low polymerization
degree, and high moisture regain may play a basic role in viscose fibers’bacteria and
fungi decomposition rate [55].
16 R. M. Nofal

Tencel is also from the regenerated cellulosic fiber category synthesized from
wood-pulp sources; lyocell is another name. It is considered a brand of rayon in the
markets without adverse impacts on nature. Generally, lyocell fiber is a renewable
and biodegradable fiber. Furthermore, the used chemicals in Tencel fiber manufac-
ture are substantially less harmful to the environment. Compared with rayon, Tencel
production does not cause harmful environmental impacts; it is not generally used as
rayon as it is still a somewhat new fiber [25]. These biodegradable fibers can be used
effectively in apparel production.
Color change and disintegration were examined, and the buried fabrics were
changed and became more brittle and thinner than the pristine fabrics. A pronounced
change was noticed after 1 month of a burial soil test for Tencel fabrics (Fig. 9)[55].
Warnock et al. [20] examined the biodegradation under soil burial tests of some
cellulosic fabrics, that is, cotton, Tencel, and rayon. Rapid biodegradation in viscose
rayon, middle biodegradation in cotton, and slow biodegradation in Tencel were
noticed [56].
Poly(Lactic Acid)
Fiber’s biodegradability, textiles or films, can be evaluated firstly by their appear-
ance. Human naked eyes can detect physical property changes. Visual appearance
observations are recorded for the polylactic acid fabrics after different intervals of
Fig. 8 Micrographs and scanning electron microscope (X500) of viscose fabric for various burial
test intervals (a) control sample, (b) 1-month burial test, (c) 4 months burial. (Adapted with
permission from Ref. [55], copyright, ICI Publishers, 2019)
Biodegradable Textiles, Recycling, and Sustainability Achievement 17

soil burial. After 1 month, there is no change, but there is a slight color change after a
4-month break due to moisture absorption. When PLA fiber was examined after a
4-month burial period, though there was a little degradation (1.2% loss in weight), it
was noticed that biodegradation would be hard under the burial conditions in soil
that applied to fibers. These findings confirm the study of Karamanlioglu et al. [57],
clearing up that no change or degradation was noted or loss in the weight of PLA
film when buried in the soil at 25 C for 120 days. PAN fiber is incredibly durable
and resists damage for long months in addition to chemical substances, and no
change or degradation was predictable for this fiber. Only a minor lightening in color
was detected after 4 months’burial soil test [55].
Polyacrylonitrile
Polyacrylonitrile fiber is durable and significantly resistant to damage for long periods
(months) and resistant to chemicals, so no degradation was predictable for this fiber.
Only a minor color change and slight lightening were detected after 120 days of the
soil burial. Scanning electron microscopy (SEM) showed minor differences in poly-
acrylonitrile. The fiber’s high resistance is based on the polymer chemical constitution.
After subjecting PAN fibers to the soil burial test, there was no observable change in
weight loss value and surface morphology. This is explained by residues or organic
substances on PAN fabrics. This is defined by the presence of deposits of bacteria and
fungi or organic substances on PAN fabrics [55].
Fig. 9 SEM micrographs and photographs (X500) of Tencel fabric at burial test variable periods
(a) control sample, (b) burial for 1 month, and soil burial for 4 months, copied from [55]
18 R. M. Nofal

Biodegradability of Cellulose Fibers in Textile Blends
Cellulosic fibers are widely used in textiles and clothing products. It is an environ-
mentally friendly fiber as when buried it can biodegrade rapidly by the action of
enzyme-secreted microorganisms (bacteria and fungi). The biodegradability behav-
ior and percent are differed from fiber to fiber of cellulosic fibers according to their
physical characteristics and chemical composition. Cellulose acetate, rayon, flax,
and cotton are all cellulosic fibers but have different crystallinity orientations,
chemical composition, degree of polymerization, and physical characteristics and
also differ in manufacturing processes and content of other ingredients (non-
cellulosic content) [58].
Biodegradation rate can be assessed by three tests: activated sludge test, burial
test in soil, and hydrolysis by enzymes. By passing the time, it was noticed that
bacteria and fungi exhibited in fibers’surface. The most cellulosic fiber subjected to
fungi is flax, and it is the most that suffer from deformation in shape due to damage
achieved by biodegradation actions. Also, cellulosic fibers such as rayon and cotton
showed damage as time passed in the soil burial test due to a few fungi. Acetate
fibers are the least damaged fibers subjected to fungi and minor deformation in shape
[54]. Conversely, after 120 days of burial test in the soil, cotton fibers are remarkably
degraded and collapsed structure happens as shown in Fig. 10, and the fiber breakage
is prominent in Tencel and cotton fibers.
Lili et al. [59] identified that cotton fabrics with jersey structure treated by three
finishing levels (scouring and bleaching processes, treatment with softener, and
adding resin) and a knitted polyester jersey substrate were examined by ASTM D
5988 03 and methods by using enzyme under specific research conditions in the
laboratory.
Indication of degradation was readily detected on the fiber’s surface in the
desiccators and the compost facility for 3 months. Degradation and decomposition
of cellulose substrates had dramatically etched away from the fabric. Scanning
electron microscope of polyester by standard method ASTM D 5988-03 after
3 months revealed minor fibers bits, peeling off the polyester surface. Some
Fig. 10 Photographs (X500) of cotton fabrics buried in soil in different periods (a) control sample,
(b) 1 month and (c) 4 months from left to right, copied from [55]
Biodegradable Textiles, Recycling, and Sustainability Achievement 19

destroyed fibers appeared on polyester fibers surface after burying for 3 months
(90 days), while major fibers are still intact [59].
The researchers subjected cotton fabrics treated with different finishes to
degrading conditions in the laboratory (soil burial test) [60]. Nine finishing
chemicals were treated with 100% cotton fabrics and were tested for up to
154 days in a controlled laboratory environment using the standard test method,
ASTM D5988-12. The fiber’s appearance and color nearly remained intact after
passing the first week. Then, the fibers begin to rot and discolor as the days go by,
brown and black patches appear, and finally, holes appear, and complete decompo-
sition and degradation occur. The antibacterial finishing of fabrics keeps their
properties intact for long periods before color changes after 3 months. First, most
of the finished materials showed a tendency for discoloration and turned brown.
The first finished fabric showing holes formation is the flame-retardant finished
fabric, which increases by passing the time. The finished fabrics with PBI only
showed accelerated degradation after 22 weeks; noticeably damaged fabric patches
appeared. Silicon softener finishes and wax &PBI finishes showed significant fabric
weight loss. At the end of the 154 days, DMUG, DMDHEU, and flame-retardant
finishes fabrics achieved a minor degradation percentage and reserved their original
shape [60].
Sharma et al. (1999) introduced and compared various retting approaches of flax
fabrics, including water, dew, and enzyme-retted methods, on flax’s thermal, chem-
ical, and physical properties [61].
Martin et al. [62] studied the impact of flax retting level on the final properties of
polypropylene/flax fiber composites. First, qualitative and quantitative experimental
techniques were used to assess the degree of retting of gradually retted flax. In
addition, water sorption studies were performed (Fig. 11).
Three mass losses are observed, as shown in Fig. 11. Water loss is indicated as the
first mass loss, while the second loss between 200 C and 400 C relates to the
degradation of pectin, hemicellulose, and cellulose, and the third demonstrates
100
1st loss 2nd loss 3rd loss
80
60
40
Weight (%)
20
0
100
R1
R3
R6
R6 Derivative
Temperature (∞C)
300
300 400 500
Weight derivative (mg.s-1)
0.02
0.00
-0.02
-0.04
-0.06
Fig. 11 Weight loss and
derivative from the mass loss
as a function of temperature.
R1 is retting for 1 day, R3 is
retting for 9 days, R6 is retting
for 19 days. (Adapted with
permission from Ref. [62],
Copyright, 2013 Elsevier)
20 R. M. Nofal

nonpolysaccharide substances degradation such as phenols [62,63]. Polysaccharides
constituting the fibers could be depolymerized at a temperature from 200 Cto
400 C, resulting in a byproduct biodegraded at elevated temperatures [64] (Fig. 12).
In the case of polyethylene terephthalate, micrographs of scanning electron
microscopes reveal slight changes in fabrics. This may be explained by the extreme
resistance of these polymers, dependent on their chemical structure [55].
Biodegradable Nonwovens and Their Applications
Nonwovens have a diverse usage in daily life, as in construction and geo, agriculture,
military, clothing field, furnishing, health and personal care, and household applica-
tions. Recently, environmental legislation is becoming a great concern, so using
biodegradable nonwoven fibers is necessary. Natural fibers such as cotton, wool,
lyocell and kenaf, jute, sisal, flax are biodegradable fibers that can be a safe choice as
a biodegradable nonwoven substrate.
It is referred to as biodegradability by exposing materials to biological factors and
their tendency to decompose. Many plastics are incredibly stable and durable, so
plastics biodegradation is slow and hard to happen. The nonbiodegradable plastics
are accumulated and reach about 25 million tons yearly; this percentage is formed
from nonwoven plastic origin [65], so trends to protect the natural environment are
growing by using nonwoven biodegradable materials and fibers.
A study [19] discussed wool wastes recycling and usage in geotextiles fields
designed to protect the ground. These products include woolen geo mats soaked with
wildflower seeds and grass [35]. As wool ropes burying in soil and exposing them to
outdoor natural weathering conditions for months (Fig. 13)[66]. The biodegradabil-
ity of wool fibers is assessed after ground burying. Pristine wool fibers breaking
strength and thickness are examined after 1–4 months of ground discarding.
Furthermore, wool fibers’chemical composition and morphology are analyzed.
Fibers extracted from ropes core produced without hydrogel and the nonwoven
Fig. 12 Photographs of polyethylene terephthalate fabrics at soil burial test at different time
intervals, (a) pristine, (b) burial for 1 month and (c) 4 months, copied from [55]
Biodegradable Textiles, Recycling, and Sustainability Achievement 21

covers are disposed after 30 months, and wool fiber scales are beginning to degrade
and destruct. In many fibers, scales are blunted, and scales edges in the cuticle layer
are harshly damaged. After 90 days of burial and disposal, additional damaging signs
have appeared clearly, especially in fibers extracted from nonwoven covering [66].
Milkweed is another natural fiber that is recently attaining a special concern in
nonwoven industries. Milkweed fiber is a white smooth, silky spore with a hollow
and rough tube that resembles a straw. This fiber is a cellulosic constitution with high
chemical resistance and a tendency to dye easily as high-quality other natural fibers,
although it has a hydrophobic nature. Milkweed floss can provide nonwovens with
excellent permeability and absorbency, softening, hydrophobicity, paper-like, high
strength, bulkiness, self-attaching and adhering, and physical alteration. Superior
agricultural production of milkweed fibers can compete in nonwoven innovative
applications, particularly filtration, purification, absorbent and permeable products,
and thermally and sound insulating materials. Natural Fibers Corporation’s subsid-
iary, Ogallala Comfort Company, Ogallala, NE, has used 75% recycled cotton and
25% milkweed fiber mattress pad [19,67].
Biodegradable Fibers in Geotextiles
Geotextiles have become an advanced approach that has been used in the construc-
tion industry and environmental engineering recently. Geotextile’s usage in
manufacturing engineered compostes of textile structures as knitted farics or non-
woven pads and tapes is utilitarian. The optimal choice of geotextile fabrics is
thoroughly related to the limited hydro-geological surroundings, textile functions
and end products, and the desired products [68].
Wool geotextiles used to control erosion were made from medically arranged
thick ropes. Geotextiles were applied to shelter the threatened slopes and ditch banks
in practical life. In addition, loose wool fibers were used to reinforce the soil. The
rate of wool biodegradation on the slope was studied. The measurements revealed
that biodegradation begins with disulfide bond cleavage, followed by peptide bond
disruption. Decomposition and biodegradation have occurred in the external cuticle
Fig. 13 Wool fibers after disposal with the hydrogel for 120 days: (a) swollen hydrogel in gape
among fibers; (b) and (c) the hydrogel stick to the fiber’s surface (magnification 500). (Adapted
with permission from Ref. [66], Copyright, 2016, RILEM)
22 R. M. Nofal

layer, then the inner cortical cells’degradation. Compounds abundant with nitrogen
are liberated during the biodegradation process. The compounds are represented as
useful fertilizers, promoting grass growth and hastening the greening of the slope.
The original morphology structure of pristine wool fibers shows that the outer
pointed scales in the cuticle layer are visible. Many unbalanced cracks in wool
sections taken in sites B-B emerged on the cuticle scales after 30 days of burial in
soil. Instantaneously, edges and corners of the scales are beginning to erode. Outer
scales became barely visible after 6 months as the destruction progressed. The outer
cuticle layer was destroyed over the next few months. Then, specific macrofibrils
with diameters of a few microns that ran parallel to the fiber’s axis became visible.
The macrofibrils remained tightly adhered to one another after 9 months. After a
year, the macrofibrils were more separated. Microphotographs taken after a more
extended period of soil exposure revealed the presence of bacteria and fungi
decomposing wool construction. The present microorganisms were moderately
small and adhered to the fiber shell [69]. Also, flax as geotextiles endure biodegra-
dation, supporting the plant’s vegetation [70].
Enzymatic Hydrolysis During Biodegradability
Microorganisms such as fungi and bacteria, in general, can be thought of as bundles
of enzymes or enzymes sources that catalyze various approaches of chemical
reactions that modify or decompose substrates. These activities applied by microor-
ganisms provide nutrients, deliver energy sources, and produce appropriate minor
fragments to create new cellular material and new cells. Bacteriological progressions
that alter the material structure permanently occur at the molecules level. Conse-
quently, the microbial analysis is influenced by chemical composition, physical
properties, and material size, affecting the microbe’s behavior with the material.
Furthermore, living organisms such as bacteria and fungi decompose and degrade
materials to produce essential nutrients for their existence and growth [8].
The Mechanisms of Enzymatic Reactions on Cellulose Fibers
Cellulose is easily biodegraded and decomposed by organisms such as bacteria and
fungi that use cellulase enzymes, and fibers of cellulose acetate need esterases
presence for the first step of biodegradation, owing to the existence of acetyl
groups [71].
To attain their nutrients, microorganisms should be soluble and have a small size
to penetrate the outer cell layer and cytoplasmic membrane to be brought into the
cell. The use of macromolecules poses a unique challenge to reducing and
decomposing molecules’volume to be easily permeable and consumed by the
cells. Polymeric molecules with high volume, like polysaccharides and proteins,
must decompose and break down outward of the cell before minor subunits or
monomers can be exhausted. Like cellulose, various bacteria and fungi produce
Biodegradable Textiles, Recycling, and Sustainability Achievement 23

extracellular enzymes that hydrolyze polymers (soluble or insoluble), one of the
most common organics in the land; its structural unit is glucose molecules linked by
b-(1 !4)-linkages. Cotton is primarily composed of this insoluble polymer. It has
been claimed that there are about 1000–1500 glucose subunits in each cellulose
molecule [72]. Extracellular cellulases hydrolyze the b-(1 !4)-linkages and ulti-
mately produce glucose monomers, represented in Eq. 1:
cellulose !oligomers !cellobiose !glucose ð1Þ
It is easily transported into microbial cells and converted into energy and carbon
for microbial growth and reproduction. Furthermore, the peptide bonds in proteins
are hydrolyzed by proteolytic enzymes leading to the following sequence of prod-
ucts (Eq. 2):
protein !polypeptides !simple peptides !amino acids ð2Þ
Amino acids are easily transported into microbial cells and can serve as energy
sources, nitrogen, carbon, and sulfur, depending on the amino acid structure, micro-
organism metabolism, and the environment in which the microorganisms grow. Only
a few microbes in a microbial community can produce the extracellular enzymes
required to hydrolyze insoluble polymers in fibers. The microbes that produce these
hydrolytic enzymes play an essential in fiber biodegradation. However, they do not
play an exclusive role in the complete biodegradation of the hydrolysis products.
Once a polymer has been broken down into soluble subunits, other microorganisms
in the community can transport these small molecules into their cells and use them as
energy sources and growth substrates. As a result, the microorganisms that produce
extracellular hydrolytic enzymes in diverse microbial communities do not consume
all of the organic constituents derived from textile fibers [8].
Figure 14 shows the structure of cellulose (R ¼OH), a homopolymer of glucose
moieties joined via b-(1 !4)-linkages. At these glycoside bonds, depolymerization
occurs (shown by the arrow in Fig. 14). Three types of cellulases catalyze these
hydrolyses: (a) endoglucanases, (b) exoglycanases, and (c) b-glucosidases. Endo-
glucanases hydrolyze internal b-(1 !4)-glycosidic bonds at random (where n and m
Fig. 14 Cellulose, chitosan, and chitin chemical structures. The arrows indicate the position of
enzymatic hydrolysis. (Adapted with permission from Ref. [74], Copyright, 2005 Woodhead
Publishing Limited)
24 R. M. Nofal

are large integers), shortening the polymer chain but increasing the concentration of
reducing sugars slowly. On the other hand, exoglycanases rapidly increase the
concentration of reducing sugars. Cellobiose is removed from the nonreducing end
of cellulose by these enzymes (n ¼1, and m is a large integer). The polymer length
decreases slowly, where only two glucose moieties are removed with each hydroly-
sis. b-Glucosidases hydrolyze cellobiose (n ¼m¼0) and short oligosaccharides
(n ¼0, and m is a small integer) to release glucose. Some cellulose-degrading
microorganisms, but not all, produce all three types of cellulases, which are usually
three different enzymes. Some cellulases, however, can have multiple activities, as
demonstrated by the cellulase separated and identified by Han et al. These enzymes
have both endo and exo activity [73].
The Mechanisms of Enzymatic Hydrolysis on Proteinic Fibers
Wool and silk are primarily composed of protein. Amino acids are the primary
building blocks of proteins, and extensive research [75,76] has revealed that wool is
composed of 18 amino acids in typical percentages. Amino acids have the general
structure H
2
N—CH(R)—COOH, where R represents the amino acid’s side group.
The proteins or polypeptides with the general structure —(NHCHRCO)n—are
obtained via multiple amino acids condensation through the reaction of adjacent
amino and carboxyl groups. The 18 amino acids in a wool combine in various ways,
resulting in approximately 170 different polypeptides with relative molecular masses
ranging from less than 10,000 to greater than 50,000 Da [75,76]. The peptide bonds
hydrolysis in wool protein generates 18 amino acids [77], as in Fig. 15.
Adjacent protein chains are often cross-linked through the disulfide bonds of the
numerous cystine moieties [77]. Thus, the wool fiber biodegradation process
required hydrolysis of peptide bonds and cleavage of disulfide bonds (Fig. 15).
The biodegradation of keratins is hindered by the cross-linking of disulfide bonds
because they hampered the peptide bonds accessibility to enzymes that hydrolyze
proteinic material. In an anaerobic environment, under the low redox conditions, as
shown in Eq. 3the disulfide bonds are reduced to release the peptide chains [8].
Fig. 15 Protein general structure (different R groups represent various amino acids). The arrow
indicates the location of enzymatic hydrolysis. (Adapted with permission from Ref. [74], Copyright,
2005 Woodhead Publishing Limited)
Biodegradable Textiles, Recycling, and Sustainability Achievement 25

chain1SSchain2þ2H !chain1SH þHS chain2
ðÞð3Þ
Microorganisms, fungi, and bacteria are involved in the process, as primarily
proteolytic and keratinolytic enzymes [78]. The first stage of degradation consists of
the disulfide bridges being split, followed by the enzymatic decomposition of keratin
into oligopeptides. Proteolytic enzymes then cause hydrolytic keratin decay via
polypeptide bonds to different amino acids, which are then used in metabolic
processes of oxidative deamination with ammonia release [78]. Lipoprotein lipase
cleaves the acyl–ester bond on the surface of wool that binds 18-methyleicosanoic
acid [79,80].
Sulfitolysis is another method to break the disulfide bond. Under alkaline condi-
tions and in the presence of sulfite, this reaction occurs. It converts cystine’s disulfide
to S-sulfocysteine and cysteine [81,82]. This causes the keratin chains to denature
(Eq. 4).
chain1SSchain2þSO3
2!chain1SSO3þSchain2

ð4Þ
The thiols fungal oxidation in cysteine residues produces sulfide, and the ammo-
nium liberated from amino acid deamination creates the alkaline conditions that help
control this reaction [83]. Extracellular proteolytic enzymes hydrolyze the peptide
bonds after the structure of keratin in wool is loosened by breaking the disulfide
bonds, as shown in Fig. 15. The hydrolysis process produces soluble peptides, which
hydrolysis to amino acids. The biodegradation of silk fibers by enzymes is similar to
wool fibers because both are protein fibers, but silk has fewer disulfide bonds in its
structure [84,85].
Evaluation of Textile Biodegradability
Polymers biodegradation is determined using three methods: laboratory, simulation,
and field tests [86], as shown in Fig. 16.
Biodegradability is investigated under ideal and practical environmental condi-
tions in the destination field, for example, burying the sample within the soil, placing
it in the lake or river, or conducting a full-scale composting process. In the biodeg-
radation simulation test, sample degradation is done within seawater, soil, or
Fig. 16 Different types of
biodegrade testing methods
26 R. M. Nofal

compost in a laboratory under controlled pH, temperature, and relative humidity
conditions. Laboratory biodegradation testing uses defined media, mostly synthetic
media, inoculated with individual or mixed microbial strains. These methods are
mechanical strength loss measurement, loss percentage of the weight, and micro-
scopic examination. Individual small molecules are released as the fiber biodegrades,
allowing chemical analyses of monomers and mineralization products. Many of
these methods are frequently collective in a single study to characterize and confirm
the biodegradation of the test material [86].
Activated sludge relative biodegradability was determined from the ratio of the
actual amount of carbon dioxide evolved to the theoretical amount of CO
2
to be
evolved, according to ASTM D 5209–92. CO
2
evolved (in mg) was obtained by
titration with HCl (0.05 N). CO
2
evolution is calculated as follows in Eqs. 5and 6:
CO2%ðÞ¼
CO2produced
CO2theoretical 100 ð5Þ
¼1:1mL HCl 12
44 total Carbon of specimen 100 ð6Þ
Another method (AATCC Soil Burial Method 30–1993) is based on measuring
the sample’s tensile strength. During the degradation time, water was supplied at a
regular interval to maintain the moisture regain of soil at 25 5%. After degrada-
tion, samples were rinsed with distilled water and dried, and the tensile strength was
measured. The evaluation of biodegradability is from the decreasing tensile
strength rate.
Enzymatic Hydrolysis
Acetate buffer and 1000 cellulase units were allowed to degrade in an incubator at
37 C for a specified time. The mixture was filtered through a 0.2 m thick membrane,
and the total organic carbon amount dissolved in the filtrate was measured. The
remaining specimens were passed through a glass filter and dried. The weight loss
ratio was estimated by determining the weight of the specimen before enzyme
hydrolysis and the weight of the remains as Eq. 7.
Weight loss ¼ARs
A100 ð7Þ
where A is the specimen weight before enzyme hydrolysis and Rs is the weight of
remains after enzyme hydrolysis.
Biodegradable Textiles, Recycling, and Sustainability Achievement 27

Weight Loss
Textile fibers or films biodegradation process causes complete or partial decompo-
sition to the substrate, resulting in an overall weight loss. Indeed, the most used
method for detecting biodegradation of textile fibers or films is to measure substrate
weight loss. Weight loss measurement is one of the biodegradation methods of flax
fibers by two strains of Cellvibrio. Polymer weight loss has also been used to
monitor biodegradation in anaerobic culture systems [87]. It displays the apparent
change in its appearance, and a large amount of decomposition occurred; the top
strip was incubated in a sterile medium, whereas the bottom stripe was set in the
viable culture [74].
Observation of a Surface Change
Optical microscopy examines the surface changes caused by biodegradation after
soil burial tests. The first indicator of textile biodegradation is the appearance change
which can be viewed with the naked eye (macroscopic scale). Usually, the colors of
the textile specimens’surfaces turned brown and black due to the action of
microorganisms.
The physical changes and microbial colonization in fibers could be detected using
microscopy techniques. Figure 17a illustrates the colonization of a poly (L-lysine)-
gellan fiber by the fungus Curvalaria sp. The fibers (1.5–2 cm in length) were
incubated with this fungus in an aqueous medium for 40 days. In Fig. 17b, the
biodegradation led to the breakdown of the fiber at the location is indicated by the
arrow. SEM is also used to view the effects of biodegradation; this provides much
higher magnification than light microscopy. SEM was used to observe the damage to
flax fiber incubated for 13 days with the cellulolytic bacterium Cellvibrio
Fig. 17 Light microscopy image of a poly (L-lysine)-gellan fiber (a), SEM image of flax fibers
after 13 days of incubation with C. fibrivorans at 28 C(b). The arrow indicates the fiber fracture.
(Adapted with permission from Ref. [88]. Copyright, 2004, American Chemical Society)
28 R. M. Nofal

fibrivorans. This image shows that the fibers remained cylindrical but were short-
ened by the microbial activity [74].
Changes in the Internal Structure
XRD is also used to investigate changes in the specimen crystallinity and internal
structure resulting from degradation [89]. The initial reaction during biodegradation
of fiber may produce minor deviations in its structure or composition. Fourier
transform infrared spectroscopy (FTIR) is often used to detect chemical changes in
the fiber [74].
Tensile Properties (Breaking Load)
During microbial depolymerization of macromolecules, hydrolysis of chemical
bonds weakens fibers, which can be identified by measuring tensile properties. For
example, in a research study, the researchers buried pieces of silk fabric (1 cm 
1 cm) in soil, which were incubated for up to 2 months after those yarns were
withdrawn from the fabric and experienced tensile loads. Before burial, the mean
breaking load of the warp yarn was 297 g-force, whereas after burial, this was
significantly decreased to only 2 g-forces.
Textile Fibers and Fabrics Recycling Procedures
Recycling technologies [10] are divided into primary, secondary, tertiary, and qua-
ternary approaches based on the raw materials used and the products produced at the
end. The direct recycling approach involves recycling a product into its original
form, such as industrial scraps; secondary recycling involves processing postcon-
sumer plastic products mechanically (melting) and transforming them into a new
product with lower chemical, physical, and/or lower-level mechanical properties.
The tertiary approach involves processes such as pyrolysis and hydrolysis, which
convert the plastic wastes into basic chemicals or monomers, or fuels. The fibrous
solid waste burning and using the generated heat refers to quaternary recycling.
Most artificial fibers are shaped from synthetic polymers, which are not biode-
gradable and need to be recycled and reused to a limited extent. After their lifetimes
are ended, those fibers and textiles are disposable in land or water, where they remain
forever as waste materials. Furthermore, as time passes, toxic pollutants are released
by nonbiodegradable materials, which are considered serious threats to living organ-
isms within the water or soil. These nondegradable durable materials can also release
poisonous gases into the air, polluting the environment. The burning of non-
biodegradable materials also produces harmful toxic gases.
Consequently, the biodegradability of fibers and textiles products is a desirable
property. However, to offer a sufficiently long usage period with the desired
Biodegradable Textiles, Recycling, and Sustainability Achievement 29

performance and comfort, these products should exhibit sufficient resistance to
microorganisms’degradation. Therefore, the textile and clothing products biodeg-
radation performance should be appropraite for thier enduse [1].
A textile discarded piece might cause pollution to the surrounding nature. Con-
sequently, the biodegradation concept will be widely used due to the growing
attempts to inhibit environmental pollution [55].
Textile remains and wastes can be classified as either pre- or postconsumer
leftover. Preconsumer waste is reproduced from the textile industries for aeronautics,
automotive, furniture, home building, mattress, home furnishings, apparel, coarse
yarn, paper, and further productions. Wastes considered postconsumer are expressed
as any form of apparel or domestic products constructed from textiles that the user no
longer wants and decides to discard. These products are discarded because they are
damaged, worn out, become an old fashion, or outgrown [90].
Sustainability in the Textile and Clothing Field
The challenges of converting renewable resources into industrial materials include
sustainability, durability, affordability, and compatibility. Sustainability provides
growth of ecological integrity and social equity to meet basic needs. The
bio-based materials designing process should service increased materials comple-
ments, developed plant bio multiplicity, diminished environmental contamination,
improved land use, and enhanced energy proficiency, while at the same time meeting
consumer requests and demands [91,92]. Besides a favorable analysis of the life
cycle, research and advancement of bio-based products should consider the limits to
maintain sustainable development.
Today’s society faces the challenges of reducing human activities’impact on the
consumption of biological resources and natural processes by manufacturing pro-
cesses, reducing poverty, and improving labor conditions. The fashion industry has a
significant impact on the environment and society. For example, 35% of material
input into fashion supply chains is wasted, while only 1% of materials producing
clothing is recycled [93].
Consequently, there is a growing demand from customers and public opinion for
environmentally and socially responsible products. Fashion brands must take into
account environmental and ethical considerations. The fashion industry is slowly
recognizing its environmental, economic, and social responsibilities and its chances
of upholding sustainability policies in manufacturing, sourcing, and marketing [94].
There is a growing awareness of sustainable and renewable-origin textile fibers in
textile design and fashion with the ever-increasing environmental problem. As a
result, sustainable textile designs made from renewable, biodegradable, and fibers
alternatives are becoming more popular. To leave a livable world for future gener-
ations, the textile industry is now focusing on biodegradable and environmentally
friendly textile resources for their designs. Natural, sustainable textile fabrics have
grown in popularity in recent years, first in the apparel industry, then in technical
textile applications such as composite material products and designs. Examples of
30 R. M. Nofal

these textile fabrics are garments, clothing, shawls, hats, liquid filtration filters,
carpets, curtains, furniture, handicraft products, mats, pillows, coasters, packaging
materials, decoration materials, decorative lampshades and lamps, ornaments for
flower wreaths, tabletop accessories, bags, chipboards, sports equipment, ropes,
papers, fishing nets, cigarette filter papers, multipurpose baskets, money papers,
wrapping papers, tea bags, and cardboard. Certainly, abaca fibers can be utilized
instead of glass fibers in the automotive industry, composite application, and tech-
nical textiles nowadays [48].
Nanotechnology plays a vital role in improving the sustainability of the environ-
ment using preventing, detecting, and removing pollutants compounds and devel-
oping environmentally friendly products [95].
The sisal plant and its products have proven to be a renewable and sustainable
natural and commercial production resource. It is truly an eco-friendly option: Not
only is it a renewable resource but it can also be easily cultivated without any
chemical fertilizers or pesticides; thus, further, it is not harmful to the environment.
In the meantime, sisal belongs to plant origin; it is also completely biodegradable. As
a result, after it has served its purpose, it will not spend an eternity taking up space in
a landfill [96].
Sustainability is defined as producing material that seems to have a lower
environmental impact. Synthetic textiles made from chemicals undoubtedly damage
the environment, affect the wearer’s health, and cause disposal issues. Natural fibers
have distinctive properties as they are organic and biodegradable, with various
superior properties. In light of this, fibers from various sources are being researched
Fig. 18 Lyocell sustainability. (Adapted with permission from Ref. [53], © Woodhead Publishing
2005)
Biodegradable Textiles, Recycling, and Sustainability Achievement 31

for their potential to improve people’s life quality all over the world, such as lyocell,
bamboo, aloe vera, banana, sisal, coffee hemp, jute, milk fiber, bean waste, corn, soy,
groundnut shell, and eucalyptus [97]. An excellent example of a sustainable fiber is
lyocell, as shown in Fig. 18. Other materials used in the fiber production process are
recovered with very little loss [53].
Fig. 18 is a brief representation of the life cycle of lyocell fibers, from creation
through to ultimate disposal and biodegradation. A sustainable fiber is made entirely
of renewable chemicals [98] and uses non-fossil-fuel-derived energy in the
manufacturing process. Renewable sources of polymeric materials provide a solu-
tion for ensuring the long-term development of environmentally and economically
appealing technology. Vink [99] set out several requirements for the ideal sustainable
material; it should offer an equivalent role and function to the product it replaces,
perform as well as or better than the existing product, be available at a lower or
competitive price, have a low environmental impact for all processes involved,
including those upstream and downstream, be manufactured from renewable
resources, contain only ingredients that are safe to both humans and the environ-
ment, and should not hurt food or water supply.
Conclusions
Because of growing environmental pollution and the prevailing trend toward envi-
ronmental protection and preserving the health of organisms, thus human health, the
use of self-degrading materials has developed an urgent necessity. The textile
industry is one of the long-standing categories of industries practiced by human.
Like the other ancient industries, it has seen a qualitative leap due to technological
and scientific progress, particularly during the European industrial revolution, which
changed many aspects of life, since the use of textiles has become widespread, not
only in clothing but also extended to carpets, filters, towels, technical fabrics,
filtration and filtering processes for the manufacture of napkins and bags, and the
strengthening of some combined materials such as glass. Synthetic textiles such as
nylon, polyester, and many other fibers are not biodegradable, remain for many years
in nature, and are harmful to human health. Natural textiles that are degradable by
various microorganisms or enzymes in nature separate and degrade into their natural
components, which can then participate in this cycle back in nature. And when it
partially decomposes, it releases toxic raw materials. Therefore, the trend was
towards using self-degrading textiles such as cotton, ceramic, silk, jute, linen, etc.
Textile recycling is how old clothes and other textiles are recovered for reuse or
material recovery. This is the basis for the textile recycling industry. The importance
of textile recycling is increasingly recognized. Every year, more than 80 billion
garments are produced worldwide. They are discarded as end-of-life waste, and as
such, textile recycling presents a significant challenge that must be addressed as we
strive to become a zero-landfill community. There is no doubt that the textile and
fashion clothing sector must reconsider its position when discussing sustainability.
More than 20 thousand types of chemicals are used in these industries that pollute
32 R. M. Nofal

river waters. In addition, the need to be working conditions worthy of human dignity
in all workplaces and production. The sustainable fashion industry today has gone
far beyond organic cotton usage only. Many fashion houses have launched complete
lines that follow environmental protection standards from the polluting remnants of
the fashion industry to preserve nature and organic resources. Materials and nature
have inspired the concept of sustainability by not using leather or animal materials in
the designs and using innovative approaches to sustainable and eco-friendly fashion.
Those in charge of this industry created environmentally friendly fabrics and
searched for alternatives to animal materials. Some fashion houses refrained from
using animal skins and fur and used the most environmentally friendly techniques
and practices, including Lyocell fabric usage identical to cotton and made from
eucalyptus trees, without harmful chemicals usage. Many fashion houses specializ-
ing sustainability have also presented modern and respectful designs of the environ-
ment simultaneously, like designs made of leather, fur, and wool, but with vegetable
sources.
Future Perspectives
Towards developing the concept of a clean environment, it is necessary to recycle the
materials and remains used in manufacturing the clothing and textiles industry to
achieve sustainability. In different usages and fields, such as clothing, furniture,
geotextiles, mats, carpets, filters, bags, tents, napkins, shoes, etc., is the way to world
free of nonbiodegradable petroleum-based synthetic fibers. The use of natural
textiles that have the ability to biodegrade as cotton, wool, silk, linen, lyocell,
kenaf, ramie, and jute, etc. are preferable.
Cross-References
▶Microbial Degradation of Textile Industrial Effluents
References
1. Connell K Y H and Kozar J M (2014) Roadmap to Sustainable Textiles and Clothing:
Regulatory Aspects and Sustainability Standards of Textiles and the Clothing Supply Chain.
Textile Science and Clothing Technology, Springer.
2. Boiten V J, Han S L-C, and Tyler D (2017) Circular Economy Stakeholder Perspectives: Textile
Collection Strategies to Support Material Circularity, Resyntex.
3. Sandoval V P, Jaca C, and Ormazabal M (2018) Towards a consensus on the circular economy.
Journal of Cleaner Production 179:605–615. https://doi.org/10.1016/j.jclepro.2017.12.224.
4. Keßler L, Matlin S A, and Kümmerer K (2021) The Contribution of Material Circularity to
Sustainability –Recycling and Reuse of Textiles. Journal of Current Opinion in Green and
Sustainable Chemistry 32:100535. https://doi.org/10.1016/j.cogsc.2021.100535.
Biodegradable Textiles, Recycling, and Sustainability Achievement 33

5. López-Martínez S, Morales-Caselles C, Kadar J, and Rivas M L (2021) Overview of Global
Status of Plastic Presence in Marine Vertebrates. Journal of Global Change Biology 27:
728–737. https://doi.org/10.1111/gcb.15416.
6. Aliotta L, Gigante V, Coltelli M B, Cinelli P, and Lazzeri A (2019) Evaluation of Mechanical
and Interfacial Properties of Bio-Composites Based on Poly (Lactic Acid) With Natural
Cellulose Fibers. International Journal of Molecular Sciences 20(4):960. https://doi.org/10.
3390/ijms20040960.
7. Lellis B, Fávaro-Polonio C Z, Pamphile J A, and Polonio J C (2019) Effects of Textile Dyes on
Health and The Environment and Bioremediation Potential of Living Organisms. Journal of
Biotechnology Research and Innovation 3(2):275–290. https://doi.org/10.1016/j.biori.2019.
09.001.
8. Blackburn R S(2006) Biodegradable and sustainable fibers, Woodhead Publishing Series in
Textiles.
9. Jambeck J R et al. (2015) Plastic Waste Inputs from Land into The Ocean. Science 347 (6223):
768–771. https://doi.org/10.1126/science.1260352.
10. Scheirs J (1998) Polymer Recycling: Science, Technology and Applications Wiley series in
polymer science.
11. Hahladakis J N, Velis C A, Weber R, Iacovidou E, and Purnell P (2018) An Overview of
Chemical Additives Present in Plastics: Migration, Release, Fate and Environmental Impact
During their Use, Disposal, and Recycling. Journal of Hazardous Materials 344:179–199.
https://doi.org/10.1016/j.jhazmat.2017.10.014.
12. Hammer J, Kraak M H S, and Parsons J R (2012) Plastics in the Marine Environment: The Dark
Side of a Modern Gift. Reviews of Environmental Contamination and Toxicology. Springer,
New York 1–44. https://doi.org/10.1007/978-1-4614-3414-6_1.
13. Ellen MacArthur Foundation (2016) The New Plastics Economy: Rethinking the future of
plastics,”Ellen MacArthur Found.
14. Elias S A (2017) Plastics in the Ocean, 1–5(12). Elsevier Inc.
15. Prambauer M, Wendeler C, Weitzenböck J, and Burgstaller C (2019) Biodegradable Geotextiles –
An Overview of Existing and Potential Materials, Geotextiles and Geomembranes 47(1): 48–59.
https://doi.org/10.1016/j.geotexmem.2018.09.006.
16. Erickson B (1999) United States Environmental Protection Agency, Today’s Chem. Work.
https://doi.org/10.1201/9781003075660-2.
17. National Research Council (1993) In Situ Bioremediation: When Does it Work? Washington,
DC: The National Academies Press. https://doi.org/10.5860/choice.32-0327.
18. Alexander M (1999) Biodegradation and Bioremediation, second ed. Acad. Press. San Diego,
CA, USA, Springer.
19. Bachmann R T, Johnson A C, and Edyvean R G J (2014) Biotechnology in the Petroleum
Industry: An Overview. International Biodeterioration and Biodegradation 86: 225–237. https://
doi.org/10.1016/j.ibiod.2013.09.011.
20. Doi Y and Fukuda K (1994) Biodegradable Plastics and Polymers. Journal of Pesticide Science
12(11). https://doi.org/10.1584/jpestics.19.S11.
21. National Research Council (1995) Alternatives for Groundwater Cleanup. Choice Reviews
Online. https://doi.org/10.5860/choice.32-5674.
22. Rana S, Pichandi S, Parveen S, and Fangueiro R (2014) Biodegradation Studies of Textiles and
Clothing Products, Textile Science and Clothing Technology book series, Springer, Singapore.
23. Eichhorn S, Hearle J W S, Jaffe, M, and Kikutani, T (2009) Handbook of Textile Fiber
Structure: Volume 1: Fundamentals and Manufactured Polymer Fibers.
24. Rasheed A (2020) Classification of Technical Textiles. In Fibers for Technical Tex-
tiles (pp. 49–64). Springer, Cham.
25. Akil H, Omar M F, Mazuki A M, Safiee S Z A M, Ishak Z M, and Bakar A A (2011) Kenaf fiber
reinforced composites: A review. Materials & Design, 32(8-9): 4107–4121.
26. Murthy H S (2018) Introduction to Textile Fibers. CRC Press.
27. Lewin M (2006) Handbook of fiber chemistry. Crc press.
34 R. M. Nofal

28. Hu X P and Hsieh Y L (1996) Crystalline Structure of Developing Cotton Fibers. Journal of
Polymer Science Part B: Polymer Physics, 34(8): 1451–1459.
29. Cook J G (2001) Handbook of textile fibers. Volume I. Manmade fibers. Volume 2. Natural
Fibers.
30. Muthu S S (Ed.) (2017) Sustainable Fibers and Textiles. Woodhead Publishing.
31. Cook J G (1984) Handbook of Textile Fibers: Natural Fibers. Elsevier.
32. Chand N and Fahim M (2020) Tribology of Natural Fiber Polymer Composites. Woodhead
Publishing.
33. Salmon-Minotte, J and Franck R R (2005) Flax. In Bast and other plant fibers Woodhead
Publishing. 94–175.
34. Ugbolue S C (2005) Fiber and Yarn Identification. Chemical Testing of Textiles 96: 1.
35. Bunsell A R (Ed.) (2018) Handbook of Properties of Textile and Technical Fibers. Woodhead
Publishing.
36. Li Z, Wang X and Wang L (2006) Properties of Hemp Fiber Reinforced Concrete Composites.
Composites part A: Applied Science and Manufacturing, 37(3): 497–505.
37. Dhakal H N and Zhang Z (2015) The Use of Hemp Fibers as Reinforcements in Composites. In
Biofiber Reinforcements in Composite Materials Woodhead Publishing: pp. 86–103.
38. Franck R R (Ed.) (2005) Bast and other Plant Fibers (Vol. 39). Crc Press.
39. Houck M M (Ed.) (2009) Identification of textile fibers.
40. Reddy S R T, Prasad A R, and Ramanaiah K (2021) Tensile and Flexural Properties of
Biodegradable Jute Fiber Reinforced Poly Lactic Acid Composites. Materials Today: Proceed-
ings, 44: 917–921.
41. Sharma H S S (1987) Studies on Chemical and Enzyme Retting of Flax on a Semi-Industrial
Scale and Analysis of the Effluents for their Physico-Chemical Components. International
Biodeterioration 23(6): 329–342.
42. Nam S and Netravali A N (2006) Green Composites I. Physical Properties of Ramie Fibers for
Environment-Friendly Green Composites. Fibers and Polymers, 7(4): 372–379.
43. Hearle J W (2007) Protein Fibers: Structural Mechanics and Future Opportunities. Journal of
materials science, 42(19):8010–8019.
44. Anuar N I S, Zakaria S, Gan S, Chia C H, Wang C, and Harun J (2019) Comparison of the
Morphological and Mechanical Properties of Oil Palm EFB Fibers and Kenaf Fibers in
Nonwoven Reinforced Composites. Industrial Crops and Products 127: 55–65.
45. Mohanty A K, Misra M, and Drzal L T (Eds.) (2005) Natural Fibers, Biopolymers, and
Biocomposites. CRC press.
46. Joseph P V, Joseph K, and Thomas S (1999). Effect of Processing Variables on the Mechanical
Properties of Sisal-Fiber-Reinforced Polypropylene Composites. Composites Science and
Technology 59(11): 1625–1640.
47. Sfiligoj Smole M, Hribernik S, Stana Kleinschek, K, and Kreže, T (2013) Plant Fibers for
Textile and Technical Applications. Advances in Agrophysical Research: 369–398.
48. Muthu S S, and Gardetti M A (Eds.) (2020) Sustainability in the Textile and Apparel Industries:
Sustainable Textiles, Clothing Design and Repurposing. Springer Nature.
49. Sinclair R (Ed.) (2014) Textiles and fashion: Materials, Design and Technology. Elsevier.
50. Edgar K J, and Zhang H (2020) Antibacterial Modification of Lyocell Fiber: A Review.
Carbohydrate Polymers 116932.
51. Eichinger D, Lotz C, and Lenring A G (1996) Lenzing Lyocell–Potential for Technical Textiles.
Lenzinger Berichte 75: 69–72.
52. Woodings, C. (2001). New developments in biodegradable non-wovens. New Fibers, 9.
53. White P, Hayhurst M, Taylor J, and Slater A (2005) Lyocell Fibers. In Biodegradable and
Sustainable Fibers. Woodhead Publishing: 157–190.
54. Park C H, Kang Y K, and Im S S (2004) Biodegradability of Cellulose Fabrics. Journal of
Applied Polymer Science 94(1):248–253.
55. Sülar V, and Devrim G (2019) Biodegradation Behavior of Different Textile Fibers: Visual,
Morphological, Structural Properties and Soil Analyses. Fibers & Textiles in Eastern Europe
27(1):100–111.
Biodegradable Textiles, Recycling, and Sustainability Achievement 35

56. Warnock M, Davis K, WolfD, and Gbur E (2009) Biodegradation of Three Cellulosic Fabrics in
Soil. Summ Ark Cotton Res, 2009: 208–211.
57. Karamanlioglu M, Preziosi R, and Robson G D (2017) Abiotic and Biotic Environmental
Degradation of the Bioplastic Polymer Poly (Lactic Acid): a Review. Polymer Degradation
and Stability 137: 122–130.
58. R. A. Young and R. M. Rowell (1987) Cellulose: Structure, Modification and Hydrolysis.
Carbohydrate Research (eds.) John Wiley and Sons, New York.
59. Li L, Frey M, and Browning K J (2010) Biodegradability Study on Cotton and Polyester
Fabrics. Journal of Engineered Fibers and fabrics 5(4).
60. Smith S, Ozturk M, and Frey M (2021) Soil Biodegradation of Cotton Fabrics Treated with
Common Finishes. Cellulose 28(7): 4485–4494.
61. Sharma H S S, Faughey G, and Lyons G (1999). Comparison of Physical, Chemical, and
Thermal Characteristics of Water-, Dew-, and Enzyme-Retted Flax Fibers. Journal of applied
polymer science 74(1): 139–143.
62. Martin N, Mouret N, Davies P, and Baley C (2013). Influence of the Degree of Retting of Flax
Fibers on the Tensile Properties of Single Fibers and Short Fiber/Polypropylene Composites.
Industrial crops and products 49: 755–767.
63. Sharma H S S, Faughey G, and McCall D (1996) Effect of Sample Preparation and Heating Rate
on the Differential Thermogravimetric Analysis of Flax Fibers. Journal of the Textile
Institute 87(2): 249–257.
64. Van de Velde K, and Baetens E (2001) Thermal and Mechanical Properties of Flax Fibers as
Potential Composite Reinforcement. Macromolecular Materials and Engineering 286(6):
342–349.
65. Pometto 3rd A L, Lee B T, and Johnson K E (1992). Production of an Extracellular
Polyethylene-Degrading Enzyme (s) by Streptomyces Species. Applied and Environmental
Microbiology 58(2): 731–733.
66. Broda J, Kobiela-Mendrek K, Rom M, Grzybowska-Pietras J, Przybylo S, and Laszczak R
(2016). Biodegradation of Wool Used for the Production of Innovative Geotextiles Designed to
Erosion Control. In Natural fibers: Advances in Science and Technology Towards Industrial
Applications. Springer, Dordrecht: 351–361.
67. Wubbe E (2002) Harvesting the Benefits of Natural Fibers. Nonwovens Industry, Jun.
68. Daria M, Krzysztof L, and Jakub M (2020) Characteristics of Biodegradable Textiles Used in
Environmental Engineering: A Comprehensive Review. Journal of Cleaner
Production 268: 122129.
69. Saldarriaga-Noreña H, Murillo-Tovar M A, Farooq R, Dongre R, and Riaz S (Eds.) (2019)
Environmental Chemistry and Recent Pollution Control Approaches. BoD–Books on Demand.
70. Alimuzzaman S, Gong R H, and Akonda M (2014) Biodegradability of Nonwoven Flax Fiber
Reinforced Polylactic Acid Bio composites. Polymer Composites 35(11): 2094–2102.
71. Puls J, Wilson S A, and Hölter D (2011). Degradation of Cellulose Acetate-Based Materials:
A Review. Journal of Polymers and the Environment 19(1): 152–165.
72. Morrison R T, Boyd R N, and Noyce D S (1960). Organic Chemistry: Allyn and Bacon, Boston,
Mass., 1959, xiv 948:10.75.
73. Han S J, Yoo Y J, and Kang H S (1995) Characterization of a Bifunctional Cellulase and Its
Structural Gene: The Cell Gene of Bacillus SP. D04 HAS Exo-and Endoglucanase Activity.
Journal of Biological Chemistry 270(43): 26012–26019.
74. Fedorak P M (2005) Microbial Processes in the Degradation of Fibers-in Biodegradable and
Sustainable Fibers: A Volume in Woodhead Publishing Series in Textiles, Elsevier.
75. Gillespie J M (1990) The Proteins of Hair and Other Hard α-Keratins. In Cellular and Molecular
Biology of Intermediate Filaments. Springer, Boston, MA: 95–128.
76. Zahn H, Föhles J, Nlenhaus M, Schwan A, and Spel M (1980) Wool as a biological composite
structure. Industrial & Engineering Chemistry Product Research and Development 19(4):
496–501.
77. Maclaren J A, and Milligan B (1981) Wool Science. The Chemical Reactivity of the Wool Fiber.
36 R. M. Nofal

78. Korniłłowicz-Kowalska T and Bohacz J (2011). Biodegradation of Keratin Waste: Theory and
Practical Aspects. Waste Management 31(8): 1689–1701.
79. Mall J K, Sims P, and Carr C M (2002) Surface Chemical Analysis of Lipase Enzyme
Treatments on Wool and Mohair. Journal of the Textile Institute, 93(1): 43–51.
80. El-Sayed W, Nofal R, and El-Sayed H (2010) Use of Lipoprotein Lipase in the Improvement of
Some Properties of Wool Fabrics. Coloration Technology, 126(5): 296–302.
81. Ruffin P, Andrieu S, Biserte G, and Biguet J (1976) Sulphitolysis in keratinolysis. Biochemical
proof Sabouraudia. Journal of Medical and Veterinary Mycology 14(2): 181–184.
82. Kunert J (1989) Biochemical Mechanism of Keratin Degradation by the Actinomycete Strep-
tomyces Fradiae and the Fungus Microsporum Gypseum: a Comparison. Journal of Basic
Microbiology 29(9): 597–604.
83. Kunert J, and Stránský Z (1988) Thiosulfate Production from Cystine by the Keratinolytic
Prokaryote Streptomyces Fradiae. Archives of Microbiology 150(6): 600–601.
84. Solazzo C, Dyer J M, Clerens S, Plowman J, Peacock E E, and Collins M J (2013) Proteomic
Evaluation of the Biodegradation of Wool Fabrics in Experimental Burials. International
Biodeterioration & Biodegradation 80: 48–59.
85. Gore P M, Naebe M, Wang X, and Kandasubramanian B (2020) Silk Fibers Exhibiting
Biodegradability & Super Hydrophobicity for Recovery of Petroleum Oils From Oily Waste-
water. Journal of hazardous materials 389: 121–823.
86. Müller R J (2005) Biodegradability of Polymers: Regulations and Methods for Testing. Bio-
polymers Online: Biology, Chemistry, Biotechnology, Applications 10.
87. Budwill K (1995) The Anaerobic Biodegradation of Poly (3-Hydroxyalkanoates).
88. Modelli A, Rondinelli G, Scandola M, Mergaert J, and Cnockaert M C (2004) Biodegradation
of Chemically Modified Flax Fibers in Soil and in Vitro with Selected Bacteria.
Biomacromolecules 5(2): 596–602.
89. Chidambareswaran P, Sreenivasan S, Patil N B, Parthasarathy M S, and Srinathan B (1987)
Analysis of Some Textile Blends using Their X-ray Diffraction Patterns. Textile Research
Journal 57(3): 167–171.
90. Hawley J M (2009) Understanding and Improving Textile Recycling: A Systems Perspective.
In Sustainable Textiles, Woodhead Publishing: 179–199.
91. Ebnesajjad S (Ed.) (2012) Handbook of Biopolymers and Biodegradable Plastics: Properties,
Processing and Applications. William Andrew.
92. Felgueiras C, Azoia N G, Gonçalves C, Gama M, and Dourado F (2021) Trends on the
Cellulose-Based Textiles: Raw Materials and Technologies. Frontiers in Bioengineering and
Biotechnology 9: 202.
93. Ellen MacArthur Foundation (2017) “A New Textiles Economy: Redesigning Fashion’s
Future,”Ellen MacArthur Found.
94. Gonçalves T, Gaio C, and Costa E (2020) Committed vs Opportunistic Corporate and Social
Responsibility Reporting. Journal of Business Research, 115: 417–427.
95. Sangeetha J, Thangadurai D, David M, and Abdullah M A (Eds.) (2016) Environmental
Biotechnology: Biodegradation, Bioremediation, and Bioconversion of Xenobiotics for Sus-
tainable Development. CRC Press.
96. Ferreira S R, Lima P R L, Silva F A, and Toledo Filho R D (2014) Effect of Sisal Fiber
Horrification on the Fiber-Matrix Bonding Characteristics and Bending Behavior of Cement
Based Composites. In Key Engineering Materials Trans Tech Publications Ltd. 600: 421–432.
97. Sachidhanandham A and Thamima S (2019) Sustainable Textiles from Lotus Asian Textile
Journal 28(3): 56–59.
98. Schué F (2000) Biopolymers from Renewable Resources. Edited by DL Kaplan
Springer-Verlag, Heidelberg, 1998: 417.
99. Vink E T, Rabago K R, Glassner D A, and Gruber P R (2003) Applications of Life Cycle
Assessment to Nature Works™Polylactide (PLA) Production. Polymer Degradation and
Stability 80(3): 403-419.
Biodegradable Textiles, Recycling, and Sustainability Achievement 37