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Effects of Alkaline Treatment on the Mechanical and Rheological Properties of Low-Density Polyethylene/Spartium junceum Flour Composites

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S. Ikhlef
S. Ikhlef
S. Ikhlef
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Sorya Nekkaa at University Ferhat Abbas of Setif
Sorya Nekkaa
Guessoum Melia at University Ferhat Abbas of Setif
Guessoum Melia
Nacerddine Haddaoui at Ferhat Abbas University of Setif-1
Nacerddine Haddaoui
  • Ferhat Abbas University of Setif-1
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Abstract and Figures

The effects of Spartium junceum (SJ) flour content, treatment time, and temperature on the mechanical and rheological properties of low density polyethylene/Spartium junceum flour (LDPE/SJ) composites were studied. SJ flour was treated with NaOH (5% wt) for 24, 48, and 72 h at 25°C and 40°C. FTIR results showed that there is a partial removal of lignin and hemicelluloses after treatment which improved the interfacial adhesion matrix/SJ flour. Also, the alkaline treatment improved notably the tensile strength and Young's modulus and increased slightly the elongation at break of LDPE/SJ composites compared to those with untreated flour.
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International Scholarly Research Network
ISRN Polymer Science
Volume 2012, Article ID 965101, 7pages
doi:10.5402/2012/965101
Research Article
Effects of Alkaline Treatment on the Mechanical
and Rheological Properties of Low-Density
Polyethylene/
Spartium junceum
Flour Composites
S. Ikhlef, S. Nekkaa, M. Guessoum, and N. Haddaoui
Laboratoire Physico-Chimie des Hauts Polym`
eres, D´
epartement de G´
enie des Proc´
ed´
es, Facult´
e de Technologie,
Universit´
eFerhatAbbas,S
´
etif 19000, Algeria
Correspondence should be addressed to S. Nekkaa, snekkaa@yahoo.fr
Received 12 September 2012; Accepted 15 October 2012
Academic Editors: Y. Habibi and A. Uygun
Copyright © 2012 S. Ikhlef et al. This is an open access article distributed under the Creative Commons Attribution License, which
permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
The effects of Spartium junceum (SJ) flour content, treatment time, and temperature on the mechanical and rheological properties
of low density polyethylene/Spartium junceum flour (LDPE/SJ) composites were studied. SJ flour was treated with NaOH (5% wt)
for 24, 48, and 72 h at 25◦Cand40
◦C. FTIR results showed that there is a partial removal of lignin and hemicelluloses after
treatment which improved the interfacial adhesion matrix/SJ flour. Also, the alkaline treatment improved notably the tensile
strength and Young’s modulus and increased slightly the elongation at break of LDPE/SJ composites compared to those with
untreated flour.
1. Introduction
Natural organic fibers from renewable natural resources offer
the potential to act as biodegradable reinforcing materials
as an alternative for the use of glass or carbon fiber and
inorganic fillers [1,2]. These fibers offer several advantages
including high specific strength and modulus, low cost,
low-density, renewable nature, biodegradability, absence of
associated health hazards, easy fiber surface modification,
and wide availability [3]. But, the main drawbacks of such
composites are their water sensitivity, their relatively poor
dimensional stability, the changing of fiber characteristics
with origin, poor adhesion to basically all matrix polymers,
and poor processability at high fiber contents.
Much work has been done on virgin thermoplastic and
natural fiber composites, which have successfully proven
their applicability to various fields of technical applications,
especially for load-bearing application. Indeed, thermoplas-
tics,suchaspolyethylene(PE)[4,5], polypropylene (PP) [6–
9], polyvinyl chloride (PVC) [10], and polystyrene (PS) [11],
have been compounded with natural fibers (such as wood,
kenaf, flax, hemp, cotton, sisal, jute, abaca, etc.) to prepare
composites.
Nekkaa et al. [12] reported that the use of silane Z-6020
for SJ fibers modification improves the dynamic mechanical
properties of PP/SJ fibers composites. Also, the results of
water absorption showed that silane treatment reduced the
water absorption capacity compared to untreated compos-
ites. The absorption of water by PP/SJ fibers composites
approaches the kinetics of a Fickian diffusion case I at
ambient temperature [13]. The alkaline treatment is also
another method to treat vegetable fibers to increase the
contact fiber matrix and thus their adhesion to each other.
So, the aim of this work is to study the effects of untreated
and treated Spartium junceum flourcontentaswellasthe
time and the temperature of flour surface modification on
the mechanical and rheological properties of LDPE/SJ flour
composites materials.
2. Experimental
2.1. Materials. The polymer matrix used in this study was
low-density polyethylene (LDPE) “B-21,” having a density
of 920 kg/m3and a melt flow index (MFI) experimentally
determined (1,51 g/10 min at 190◦C).
2ISRN Polymer Science
Spartium junceum flour was prepared in our laboratory
from fibers obtained from local sources. The shurb can be
cultivated manually, and then the fiber was cleaned and
crushed. The dimension average particle size was 100 μm.
2.2. Treatment of Spartium junceum Flour. The flour was
treated with sodium hydroxide (NaOH) aqueous solution
(5% w/v) for 24, 48, and 72 h at two different temperatures:
25◦Cand40
◦C. Then, it was washed with distilled water until
all the sodium hydroxide was eliminated, and the washing
water pH was neutral. Subsequently, flour was dried at 60◦C
until constant weight was found.
2.3. Compounding and Processing. The composite materials
LDPE/SJ were prepared by mixing the polymer matrix
and the flour in a two-roll mixer (Busto Arsizio) at a
temperature of 158◦C and a mixing rate of 32 rpm/min for
10 min. Different composites LDPE/SJ flour were prepared;
the pretreated and treated SJ flour amounts added were 10,
20, and 30 wt%.
2.4. Measurements Characterization Methods
2.4.1. FTIR Spectroscopy. The spectrometer, FTIR-8400S-
Shimadzu, was used in the transmission mode with a
resolution of 2 cm−1in the range of 4500–500 cm−1.The
samples were tested after being pressed with 2.5 wt% of KBr
to form a disc.
2.4.2. Tensile Test. Specimens tensile test was conducted at
23 ±2◦C using a universal testing machine (Zwick Postfash
4350) with a crosshead speed of 5 mm/min according to ISO
527-3 standard. Five specimens of each composition were
tested, and the average value reported.
The tensile properties (Young’s modulus E, tensile
strength σr, and elongation at break εr)areevaluatedfrom
the stress-strain curves.
2.4.3. Impact Strength. Izod and Charpy impact measure-
ments were carried out with a Ceast Resil Impact instrument
in accordance with EN ISO 180 standard at 23 ±2◦C. The
capacity of the pendulum is 7.5 Kg. The impact strength
of unnotched specimens (an) and the impact strength of
notched specimens (ak)werecalculated.
2.4.4. Hardness. Shore D hardness of the samples was
evaluated by using a hardness tester. Samples were placed on
a horizontal surface. Tester was kept in vertical position and
pressed on the specimen so that the presser foot was parallel
to specimen. Five readings at different points were noted,
and average value is reported according to NF EN ISO 868
standard.
2.4.5. Differential Scanning Calorimetry Studies. Adifferen-
tial scanning calorimeter (NETZSCH.DSC 200 PC) was used.
Theheatingratewas10
◦C per min, and the temperature
80
70
60
50
40
30
20
10
4000 3500 3000 2500 2000 1500 1000 500
Wavenumbers (cm−1)
Absorbance
(1) Untreated
(2) 24 h
(3) 48 h
(4) 72 h
1
2
3
4
Figure 1: FTIR spectra of Spartium junceum flour untreated and
treated with NaOH at different times at 25◦C.
ranged from 20◦C to 220◦C. A value of ΔH∞equal to 280 J/g
for a pure crystalline LDPE is used [14].
Enthalpies of fusion ΔHmwere evaluated from the peak
area of fusion. The crystallinity Xcis then determined by the
following relationship:
Xc(%)=
ΔHm
ΔH∞
·100, (1)
Xc(%) is degree of crystallinity; ΔHmis experimental
enthalpy of fusion; ΔH∞is Enthalpy of fusion of a 100%
LDPE cristalline sample.
3. Results and Discussions
3.1. FTIR Spectroscopy. Figure 1 shows the FTIR spectra of
untreated and alkaline treated Spartium junceum flour for
different times of treatment at 25◦C.
The intensity of 3400 and 1052 cm−1peaks assigned to
the stretching vibrations of hydroxyl groups of cellulose and
C–O groups of hemicelluloses [15], respectively, decreased
with the chemical treatment of the filler. The alkaline
treatment of the SJ flour induces the partial removal of
hemicellulose and lignin, because of the disappearance of
the band characterizing the carbonyl group observed at
1737 cm−1[16]. The peak at 1644 cm−1in the untreated SJ
flour is associated with the adsorbed water. The decrease
in this peak intensity in the chemically treated SJ flour is
due to the partial removal of hemicelluloses. The weak peak
noticed between 1423 and 1412 cm−1is assigned to the in
plane bending deformation of –CH2of lignin. The stretching
vibrations of C=C bonds in aromatic rings of lignin are
observed at approximately 1577 and 1507 cm−1[17]. The
sharp peak observed at 2926 cm−1reflects C–H asymmetric
deformation of lignin. In conclusion, the alkaline treatment
changes the supermolecular structure of flour while the
chemical structure is not significantly affected. Due to the
intra- and interfibrillar swelling, the accessibility of flour
changes drastically.
ISRN Polymer Science 3
10 20 30 40 50 60 70 80
0
10
20
30
40
Weight loss (%)
Time (hour)
Figure 2: Influence of time of treatment at 25◦Conthepercentage
of weight loss flour.
The possible chemical reaction between the alkaline
solution and the hydroxyl groups of the SJ flour is as follows:
Fiber–OH + Na–OH −→ Fiber–O−Na++H
2O.(2)
3.2. Weight Loss. Natural fiber contains mainly cellulose,
hemicellulose, and lignin. Hemicellulose is a compound
containing several molecules of sugar and substances which
are soluble in water or in alkaline solution. Lignin is also
soluble in alkaline solution. It is possible that some of the
hemicellulose and lignin will dissolve during the treatment
which will cause a decrease in the mass of SJ flour [15].
Figure 2 shows the effect of the treatment time on the
percentage of weight loss of SJ flour at 25◦C. We note that
the evolution of the percentage of weight loss is progressively
important over the first 48 hours of treatment then begins to
stabilize after a treatment period of 48 hours.
3.3. Tensile Properties
3.3.1. Effects of Flour’s Content and Treatment. Figures 3,4,
and 5reveal the effects of the flour content and the treatment
time on the tensile strength, Young’s modulus, and the
elongation at break of LDPE/SJ composites. The addition of
unmodified SJ flour to LDPE matrix induces a sharp decrease
in the tensile strength (Figure 3). Also, the tensile strength of
the composites decreased with increasing flour loading, due
to the weak interfacial adhesion and the low compatibility
between the hydrophilic flour and hydrophobic PE [18–20].
Moreover, a significant increase in Young’s modulus with
increasing SJ flour content is noticed (Figure 4). Thus, the
rigidity of SJ flour, which is higher than that of the thermo-
plastic matrix LDPE, contributes significantly to the increase
of the rigidity of the whole material. At the same time,
a noticeable decrease in the elongation at break prevents
the elasticity of the composite material (Figure 5). On the
other hand, the weak interaction matrix/flour facilitates the
separation at the interface and promotes debonding, which
results in a reduced deformability [7].
0 5 10 15 20 25 30
0
2
4
6
8
10
12
Flour’s content (%)
Untreated 48 h
24 h 72 h
Tensile strength σr(MPa)
Figure 3: Effect of flour content and time of treatment at 25◦Con
the tensile strength of LDPE/SJ flour composites.
0 5 10 15 20 25 30
100
200
300
400
500
600
700
Young’s modulus E (MPa)
Flour’s content (%)
Untreated 48 h
24 h 72 h
Figure 4: Effect of flour content and time of treatment at 25◦Con
the Young’s modulus of LDPE/SJ flour composites.
However, the superior tensile strength of alkali-treated
fabrics may be attributed to the fact that the alkaline
treatment improves the adhesive characteristics of the flour
surface by removing natural and artificial impurities [21].
In addition, the alkaline treatment leads to fiber fibrillation
which increases the effective surface area available for contact
with matrix polymer [22,23].
3.3.2. Effect of Temperature. The effect of treatment tem-
perature on the tensile properties of LDPE/SJ (70/30) com-
posites with NaOH-treated flour at different temperatures is
shown in Tab l e 1 . In general, the values of tensile strength,
Young’s modulus, and the elongation at break of LDPE/SJ
composites with flour treated at 25◦C are higher than
4ISRN Polymer Science
Tab l e 1: Effect of temperature on the tensile strength, Young’s modulus, and elongation at break of composites LDPE/SJ (70/30) with flour
treated with NaOH at different times.
Treatment time (h) σr(MPa) E(MPa) εr(%)
T(25◦C) T(40◦C) T(25◦C) T(40◦C) T(25◦C) T(40◦C)
24 6,50 3,75 491,00 455,00 7,02 4,69
48 8,60 4,66 563,00 310,00 10,28 3,58
72 9,43 8,90 194,00 325,00 5,12 4,09
Tab l e 2: Values of impact strength (Izod) of composites LDPE/SJ composite with treated and untreated flour.
Composites an(KJ/m2)ak(KJ/m2)
LDPE/SJ (100/0) No break No break
Untreated flour
LDPE/SJ (90/10) No break 29,72
LDPE/SJ (80/20) 30,67 17,28
LDPE/SJ (70/30) 18,01 9,25
Treated flour (24 h)
LDPE/SJ (90/10)/25◦C No break No break
LDPE/SJ (80/20)/25◦C No break 24,59
LDPE/SJ (70/30)/25◦C 29,37 13,84
LDPE/SJ (70/30)/40◦C 18,86 9,42
Treated flour (48 h)
LDPE/SJ (90/10)/25◦C No break No break
LDPE/SJ (80/20)/25◦C No break 30,46
LDPE/SJ (70/30)/25◦C 27,45 14,38
LDPE/SJ (70/30)/40◦C 13,28 7,58
Treated flour (72 h)
LDPE/SJ (90/10)/25◦C No break No break
LDPE/SJ (80/20)/25◦C No break 21,63
LDPE/SJ (70/30)/25◦C 23,54 12,82
LDPE/SJ (70/30)/40◦C 18,20 7,94
those of composites with the flour treated at 40◦C. This is
undoubtedly due to the decrease in the cellulose fraction in
the vegetable flour with increasing temperature, which causes
depolymerization and thus the weakening of the flour, and
therefore the reduction of the mechanical properties [4].
3.4. Impact Strength
3.4.1. Effects of Flour’s Content and Treatment. The impact
strength of the composites is significantly lower than of the
neat polyethylene matrix (Tabl e 2 ). The stiffer cellulose flour
acts as stress concentrators in the polymer matrix, reducing
therefore the crack initiation energy and consequently the
impact strength of the composites [8]. This occurs because
of the chemical incompatibility between the thermoplastic
polyolefin and the polar flour, resulting in low interfacial
adhesion [24].
Also, it was noticed that notched specimens showed
lower resilience than unnotched ones because the energy
of notched specimens presents only that of the crack
propagation, while that of unnotched specimens includes the
initiation and propagation of the crack.
The treatment of the flour surface shows an improvement
of the impact strength of composites with treated flour
compared to those with unmodified flour. The values
of impact strength of the different tested composites are
listed in Tabl e 2 . The treatment of the flour improves the
compatibility and promotes the ability to dissipate energy
during fracture.
On the other hand, processing time of 24 and 48 hours
givescompositeswithhighervaluesofimpactstrength
than those of the processing time of 72 hours. This may
be due to the weakening of flour; a long processing time
causes a significant reduction in lignin, which weakens the
flour.
3.4.2. Effect of Temperature. According to the values in
Tab l e 2 , we find that the impact strength of the specimens
with flour treated at 25◦C is higher than that with the flour
treated at 40◦C. This confirms the results found by the tensile
test where the increase in the processing temperature of
the flour causes a decrease in mechanical properties of the
composite material.
ISRN Polymer Science 5
0 5 10 15 20 25 30
0
20
40
60
80
100
120
140
Flour’s content (%)
Elongation at break εr(%)
Untreated 48 h
24 h 72 h
Figure 5: Effect of flour content and time of treatment at 25◦Con
the elongation at break of LDPE/SJ flour composites.
0 5 10 15 20 25 30
0
10
20
30
40
50
60
70
Hardness (shore D)
Flour’s content (%)
Untreated 48 h
24 h 72 h
Figure 6: Effect of flour content and time of treatment at 25◦Con
the hardness of LDPE/SJ flour composites.
3.5. Hardness Results
3.5.1. Effect of Flour’s Content and Treatment. Figure 6 shows
the variations of the hardness of composites with untreated
flour and NaOH-treated flour for different times at 25◦C
as function of flour content. From the figure, we can
deduce that the treatment does not significantly influence
the composites hardness. This can be explained by the
heterogeneity of the composite due to factors related to the
flour.
3.6. Melt Flow Index
3.6.1. Effect of Flour’s Content and Treatment. Adecrease
in the melt flow index with the increase of flour content
0 5 10 15 20 25 30
0
0.3
0.6
0.9
1.2
1.5
1.8
Flour’s content (%)
Untreated 48 h
24 h 72 h
Melt flow index MFI (g/10 min)
Figure 7: Effect of flour content and time of treatment at 25◦Con
the melt flow index of LDPE/SJ flour composites.
Tab l e 3: Values of the melt flow index of composites LDPE/SJ
(70/30) with treated flour at different times and at different
temperatures.
Treatment time (h) Melt flow index (g/10 min)
T(25◦C) T(40◦C)
24 1,11 1,23
48 0,98 1,45
72 1,11 1,17
is reported according to Figure 7. This reflects the het-
erogeneity of the materials. The probability of aggregates
formation increases with increasing SJ flour content. Thus
aggregation depends on the composition, while the value
of the maximum is determined by adhesion and the load
carried by the SJ flour particles [25].
3.7. Effect of Temperature. According to Figure 7 and the
values reported in Tabl e 3 , there is a slight improvement of
the composites melt flow index values after treatment, but
the increasing of the process temperature does not affect the
values of the melt flow index. This behavior suggests that
the interfacial adhesion between the matrix and the flour is
higher for modified flour, and that the level of dispersion of
the flour within the polymeric matrix is also improved. The
results confirm that the treatment improves the dispersion
and the interfacial adhesion with the matrix.
3.8. Differential Scanning Calorimetry Studies
3.8.1. Effect of Flour’s Content and Treatment. Figure 8 shows
the thermograms of LDPE/untreated Spartium junceum
flour composites. The incorporation of untreated Spartium
junceum flour to the polymeric matrix has no significant
impact neither on the melting temperature nor on the shape
of the melting peak. These results are in agreement with those
6ISRN Polymer Science
Tab l e 4: Thermal Properties of LDPE/untreated and treated Spartium junceum flour composites.
Samples Tm(◦C) first scan Tf(◦C) second scan ΔHm(J/g) Xc(%)
LDPE 113,00 112,50 91,07 32,52
LDPE/SJ (90/10) 113,00 112,70 104,14 37,19
LDPE/SJ (80/20) 112,50 112,30 112,2 40,07
LDPE/SJ (70/30) 113,50 112,30 132,14 47,19
LDPE/SJ (70/30) treated at 25◦C, 24 h 112,50 113,30 131,80 46,76
LDPE/SJ (70/30) treated at 25◦C, 48 h 112,50 113,30 135,60 48,42
LDPE/SJ (70/30) treated at 25◦C, 72 h 112,50 113,30 132,87 47,45
(1) LDPE
(2) LDPE/SJ flour (90/10)
(3) LDPE/SJ flour (80/20)
(4) LDPE/SJ flour (70/30)
1
2
3
4
Temperature (◦C)
50 100 150 200
1
0
−1
−2
−3
−4
Heat flow (W/g)
Figure 8: DSC thermograms of LDPE and different LDPE samples
filled with untreated Spartium junceum flour.
presented by Bendahou et al. [26], Av´
erous et al. [27], and Le
Digabel et al. [28].
According to Tab l e 4, it is clear that the crystallinity χc
increases with untreated flour loading. Thus, the cellulosic
filler acts as nucleation sites which alter the kinetics of crys-
tallization of the semicrystalline polymer. These results agree
with those found by Joseph et al. [29] who noticed a slight
increase of the crystallinity of PP/sisal fibers composites with
increasing the fiber content. Also Nekkaa et al. [30] showed
that the incorporation of SJ fiber in PP caused an apparent
increase in the crystallinity.
Figure 9 shows the comparison of DSC thermograms of
70/30 LDPE/SJ composites based on the flour treated with
NaOH at 25◦Catdifferent times. According to the last figure
and the values reported in the Tabl e 4 , we notice that the
processing time has no effect on the composites-melting
temperature and crystallinity.
4. Conclusion
The SJ flour surface treated with alkaline treatment improved
notably the tensile strength, Young’s modulus, and the
impact strength but slightly the elongation at break of the
50 100 150 200
1
2
3
1
0
−1
−2
−3
−4
−5
Heat flow (W/g)
Temperature (◦C)
(1) 24 h
(2) 48 h
(3) 72 h
Figure 9: DSC thermograms of composites LDPE/treated Spartium
junceum flour at 25◦C (70/30).
composites LDPE/SJ compared to composites with untreated
flour. Also, the values of these parameters for the composites
with the SJ flour treated at the temperature of 25◦Carehigher
than those of the composites with the SJ flour treated at 40◦C.
A decrease in the melt flow index with the increase of
the flour content is noticed. But, a slight improvement of the
values of the composites MFT is observed with the treatment.
The incorporation of SJ flour to LDPE has no significant
impact on the melting temperature but increases the crys-
tallinity.
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... This shows the influence of alkali washing of fibers on FS of WPCs, added with APP. Ikhlef et al. (2012) studied the effect of alkali washing and reported improvement in strength properties of composite due to improved interfacial adhesion between matrix and cellulosic fiber. The addition of boron compound in the formulation resulted in significant loss in strength (both tensile and flexural) and flexural modulus of APP incorporated composites irrespective of fiber treatment. ...
Effect of borax-boric acid and ammonium polyphosphate on flame retardancy of natural fiber polyethylene composites
Article
Full-text available
  • Jun 2022
  • MADERAS-CIENC TECNOL
Wood fiber filled high density polyethylene composites (WPCs) were prepared using twin screw extruder and maleated polyethylene as a coupling agent. Bamboo fibers were initially treated with alkali (NaOH), boric acid - borax (Ba-Bx) and borax (Bx). The treated and untreated fibers were used in combination with ammonium polyphosphate (APP) to investigate their synergistic effects on thermal stability, flame retardancy and mechanical properties. Alkali pretreatment (5 % NaOH) of fibers showed significant improvement in performance of APP by increasing thermal stability in WPCs. The derivative thermogravimetric (DTG) results indicate significance of Ba-Bx in promoting char induction at lower temperatures (340 ºC) and thereby, improved the thermal stability in WPCs. Flammability decreased with addition of flame retardant additives. As compared to pure WPCs, composites containing APP 10 % / Ba-Bx 5 % exhibited maximum reduction in average heat release rate (HRR) by 69 %, peak heat release rate (PHRR) by 59 %, total heat released rate (THR) by 48 % and also increased time to ignition (TTI) by 62 %. However, no significant difference was found among the combinations i.e., APP with or without compounds towards reducing the flammability of WPCs. The strength properties also reduced significantly when boron compounds were added along with APP. In general, APP alone (15 %) is enough for imparting thermal stability and flame retardancy in WPCs.
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... The O-H bond reoccurred as a result of the SBBWF elongation after treatment with NaOH at rapid variation in the transmitting percentage. The lignin from C=C bond reduced after treatment with NaOH by increasing transmittance from 92.57 to 97.049% 2 (Agarwal & Reiner, 2009;Ikhlef et al., 2012). The absorption band located at 1315 to 1025.0cm¯¹ is a characteristic of C-C stretching and C-O stretching, which were attributed to the carboxyl group of hemicelluloses with also a change in the peak transmittance (Ismail et al., 2002). ...
1647516491913 1647513856300 FEIC 2022 BOOK OF PROCEEDINGS[1]
Conference Paper
Full-text available
  • Mar 2022
The production of bio-methane from cow-dung and tannery by product was carried out. The work focuses on the production of biogas anaerobically through the codigestion of cow-dungs and tannery waste and also to reduce the concentration of sulphide by direct inclusion of facultative lagoon sediment with sodium and calcium alginate. Comparison of the efficacy of various tannery beam house effluents as substrate diluents indicated that the soaking liquor was most favourable. The highest bio-methane concentration of 11.8%v/v was obtained from the use of Soaking liquor, as against 8.8%v/v, 1.2%v/v, and 4.1%v/v when deliming liquor, liming liquor and a combination of the entire beam house liquors were used respectively. Various tannery fleshing to cow-dung ratio of 1:0, 1:0.5, 1:1 and 1:2 were investigated. The optimum was established to be ratio 1:2 as indicated by the highest methane concentration of 45.5%v/v as against 1.9% by volume, 4.1% by volume, 7.3% by volume, for 1:0, 1:0.5 and 1:1 respectively. It was observed that a minute concentration of sodium and calcium alginates (0.01% wt/v) which was introduced from the beginning of the anaerobic digestion cycle possessed the efficacy to increase methane concentration and reduce the hydrogen sulphide concentration of the system. The alginates acted as chelating ligands thereby boosting methane production and reducing sulphide concentration. Methane concentration was significantly boosted to 70.1%v/v and 63.8%v/v with the addition of sodium alginate and calcium alginate beads respectively, as against 45%v/v for a similar digestion sample without alginate. In all, sodium alginate had a better performance than calcium alginate beads both of 0.01% wt/v. However, a rise in calcium alginate to about 0.03% wt/v performed better than sodium alginate of 0.01% wt/v. In addition, inclusion of the alginates to the digestion system shortens the retention time for biogas production and the release of hydrogen sulphide gas. This work therefore recommends soaking liquor as diluent in the anaerobic digestion of tannery fleshing, utilizing cow dung and tannery waste (fleshing) in the ratio of 2:1 for anaerobic co-digestion respectively, the use of facultative lagoon sediments as basic inoculant and the use of sodium and calcium alginates (0.01% wt/v) acting as chelating ligands to remove hydrogen sulphide and boost dry methane production above 20% with very good combustion characteristics.
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... The O-H bond reoccurred as a result of the SBBWF elongation after treatment with NaOH at rapid variation in the transmitting percentage. The lignin from C=C bond reduced after treatment with NaOH by increasing transmittance from 92.57 to 97.049% 2 (Agarwal & Reiner, 2009;Ikhlef et al., 2012). The absorption band located at 1315 to 1025.0cm¯¹ is a characteristic of C-C stretching and C-O stretching, which were attributed to the carboxyl group of hemicelluloses with also a change in the peak transmittance (Ismail et al., 2002). ...
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Optimization of alkali modified breadfruit peel flour-LDPE composite for car mirror casings
Article
  • Jan 2025
The research was carried out to optimize the properties of alkali modified breadfruit peel flour-low-density polyethylene (BPF-LDPE) composite. The BPF-LDPE composite was produced for both alkalized with NaOH (NS-BPF-LDPE) and unmodified (UN-BPF-LDPE) composite by compounding bread fruit peel fiber (BPF) and low-density polyethylene (LDPE). The BPF was blended at 5–25 wt.% fiber content ( A 1 ) and 20–100 mesh (850–150 µm) particle size ( A 2 ). The variation of A 1 and A 2 on the tensile strength ( U TS ), stretching modulus ( U TM ), elongation ( U E ), flexural strength ( U FS ), bending modulus ( U FM ), hardness ( U H ), Impact strength ( U IS ) and water absorption resistivity ( U WAR ) of the BPF-LDPE composite were verified, respectively. Response surface methodology (RSM) was implemented for this process. The scanning electron microscope (SEM) was tested on NS-BPF-LDPE and UN-BPF-LDPE composite, respectively. The results noted that at optimal state, A 1, A 2, U TS , U E , U TM , U FS , U FM , U H , U IS and U WAR, were 150 µm (100 mesh), 25 wt.%, 7.638322 MPa, 8.105433 %, 0.341301 GPa, 23.48253 MPa, 0.331741 GPa, 167.2593 Pa, 45.28871 kJ m ⁻² and 4.730205 %, respectively. After the modeling process, the error detected from experimental related results and that RSM was <2.9445 %. All the RSM predicted responses attributed significant correlation indicating good prediction of NS-BPF-LDPE composite in production of engineering component.
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Effect of particle size on the properties of avocado pear wood fiber/low-density polyethylene composite enhanced by pretreatment
Article
  • Dec 2023
The work entailed the influence of particle size on the characteristics and water absorption resistance of avocado pear wood fiber/low-density polyethylene (APWF/LDPE) composite enhanced by pretreatment. The fiber particle of 100, 80, 60, 40, and 20 mesh (150, 180, 250, 425, and 850 µm) for the avocado wood fiber (APWF) was infused in the resin. Each particle of the fiber with fiber content of 5–25 wt% for the untreated, pretreated with NaOH, NaOH + CH 3 COOH, and NaOH + CH 3 COOH + MAPE was intermixed in the resin to produce the APWF/LDPE composites, respectively. The APWF/LDPE composites were analyzed on the properties, water absorption resistance, Fourier transform infra-red, and scanning electron microscopy. The study exhibited that mechanical properties and water absorption resistance of the APWF/LDPE composite were improved at lower particle of the fiber triggered by treatment. The best properties were confirmed at 150 µm of APWF pretreated with NaOH + CH 3 COOH + MAPE when compounded with the resin. These were proportional to 15.92 MPa, 0.867 GPa, 41.39 MPa, 0.662 GPa, 683 Pa, 84.04 kJ m ⁻² , and 2.44 % for tensile strength, elastic modulus, flexural strength, bending modulus, Brinell hardness, impact strength, and water absorption resistance, respectively. The APWF/LDPE composite for NaOH + CH 3 COOH + MAPE pretreated is recommended for interior cabinet of an automobile.
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Alkali Konsantrasyonunun Odun Unu Takviyeli PVC Kompozitlerin Mekanik Özelliklerine Etkisi
Article
Full-text available
  • Mar 2022
Bu çalışma, modifiye edilmiş odun ununun termoplastik kompozitler üzerindeki etkisini belirlemek amacıyla yapılmıştır. Bu amaçla, farklı konsantrasyonlarda (%0-3-6-12) alkali (sodyum hidroksit (NaOH)) ile muamele edilmiş odun unu, polivinil klorür (PVC) polimerine ilave edilerek odun-PVC kompozitleri üretilmiştir. Alkali muamelesinin odun-PVC kompozitlerin mekanik özelliklerine etkisini tespit etmek için çekme direnci, çekmede elastikiyet modülü, eğilme direnci, eğilmede elastikiyet modülü ve sertlik değerleri belirlenmiştir. Alkali ile muamele edilmiş odun unu içeren kompozit numunelerin çekme direnci, eğilme direnci ve elastikiyet modülü değerleri muamele edilmemiş odun unu içerenlerinkine kıyasla daha yüksek tespit edilmiştir. En yüksek çekme ve eğilme direnci değerleri %6 NaOH muameleli odun unu içeren kompozit numunesinde tespit edilmiştir. Ayrıca, kompozitlerin sertlik değerlerinin, alkali muamelesinden çok fazla etkilenmediği görülmüştür. Bunlara ek olarak, termogravimetrik analiz (TGA) sonuçları, alkali muamelesinin kompozit malzemelerin termal kararlılığında artışa sebep olduğunu göstermiştir..
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Novel compatibilizers and plasticizers developed from epoxidized and maleinized chia oil in composites based on PLA and chia seed flour
Article
  • May 2022
  • EUR POLYM J
Novel compatibilizers and plasticizers derived from epoxidized chia seed oil (ECO) and maleinized chia seed oil (MCO) have been applied in composites based on poly(lactic acid) (PLA) and 15 wt.% chia seed flour (CSF). Results obtained have been compared to conventional silane coupling agent, (3-glycidyloxypropyl) trimethoxysilane (GPS), and a petroleum-based compatibilizer, poly(styrene-co-glycidyl methacrylate) copolymer (Xibond, ®). The compatibilization effect of green composites were assessed by FTIR. The addition of all four compatibilizers improved the ductile mechanical and thermal properties of the composites. The morphology analysis revealed an improvement of interfacial adhesion of the CSF particles into the PLA matrix. In particular, ECO and MCO composites showed a roughness with long filaments in their morphology which plays a crucial role in improving the ductile properties highly. The elongation at break was 10 and 8 times higher using ECO and MCO, respectively, compared to uncompatibilized composite. Moreover, the composites manufactured showed low values (<9%) in the water uptake assay and a negligible compostability delay. The use of novel compatibilizers based on modified vegetable oils could mean an interesting proposal to obtain an entirely environmentally friendly composite with a remarkable ductile property.
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Modeling and simulation of tensile properties of r-LDPE/GSF composite using the response surface methododology
Article
  • Mar 2022
In this study, the ultimate tensile strength (UTS), elongation (ELG) and tensile modulus (TEM) of a recycled low-density polyethylene groundnut shell fiber composite (r-LDPE/GSF) were modeled and simulated when considered particle size (PS) and fiber content (FC) of groundnut shell fiber (GSF) by applying response surface techniques (RSM) for structural application. The deposit of recycled low-density polyethylene (r-LDPE) and GSF, an agro-waste, were combined in the production of r-LDPE/GSF composite at PS of 50–70 mesh (300–212 µm) and FC of 10–30 wt% of the GSF. The manufactured r-LDPE/GSF composite was tested for UTS, ELG and TEM and optimized by considering these process variables of GSF, PS and FC with RSM. The outcome indicated that at optimum condition, the UTS, ELG and TEM were 8.5072 MPa, 12.83% and 0.94007 GPa, respectively. The parameters at this point were PS and FC of 60.48 mesh (250 µm) and 30 wt%, respectively. The coefficient of determination ( R ² ) was close to 0.99. The percentage of relative errors between raw experimental reading and the RSM was <0.16. Based on the result of the work, the predicted RSM data on tensile properties of r-LDPE/GSF composite shows that is a potential engineering material for structural application.
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Mechanical behavior of natural fiber composites
Article
Full-text available
  • Dec 2011
The use of natural fibers as reinforcement in polymeric composites for technical applications has been a research subject of scientists during the last decade. There is a great interest in the application of sisal fiber as substitutes for glass fibers, motivated by potential advantages of weight saving, lower raw material price, and ecological advantages of using green resources which are renewable and biodegradable. Castor oil, a triglyceride vegetable that has hydroxyl groups, was reacted with 4,4’ diphenylmethane diisocyanate (MDI) to produce the polyurethane matrix. Woven sisal fibers were used untreated and thermal treated at 60°C for 72h, and the composites were processed by compression molding. The present work study tensile behavior at four composites: dry sisal/polyurethane, humid sisal/polyurethane, dry sisal/phenolic and humid sisal/phenolic resin. The moisture content influences of sisal fibers on the mechanical behaviors were analyzed. Experimental results showed a higher tensile strength for the sisal/phenolic composites followed by sisal/polyurethane, respectively. In this research, sisal composites were also characterized by scanning electron microscopy.
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Acetylation of jute and infrared spectra of acetylated jute
Article
A simple and quick method for the partial acetylation of jute is reported. The infrared spectrum of the acetylated jute indicated a shift of the carbonyl absorption band to a higher wave number. Differential IR spectra of jute and acetylated jute showed absorption for acetate of phenolic hydroxyl groups, indicating acetylation of the lignin component with unprotected hydroxyl groups in the fibre. The acetylated fibre, though it lost its strength to some extent, showed reduced hygroscopicity and dye uptake and increased resistance to microbial damage.
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Mechanical properties and morphology of impact modified polypropylene - Wood flour composites
Article
The mechanical properties and morphology of polypropylene/wood flour (PP/WF) composites with different impact modifiers and maleated polypropylene (MAPP) as a compatibilizer have been studied. Two different ethylene/propylene/diene terpolymers (EPDM) and one maleated styrene–ethylene/butylene–styrene triblock copolymer (SEBS–MA) have been used as impact modifiers in the PP/WF systems. All three elastomers increased the impact strength of the PP/WF composites but the addition of maleated EPDM and SEBS gave the greatest improvements in impact strength. Addition of MAPP did not affect the impact properties of the composites but had a positive effect on the composite unnotched impact strength when used together with elastomers. Tensile tests showed that MAPP had a negative effect on the elongation at break and a positive effect on tensile strength. The impact modifiers were found to decrease the stiffness of the composites. Scanning electron microscopy showed that maleated EPDM and SEBS had a stronger affinity for the wood surfaces than did the unmodified EPDM. The maleated elastomers are, therefore, expected to form a flexible interphase around the wood particles giving the composites better impact strength. MAPP further enhanced adhesion between WF and impact-modified PP systems. EPDM and EPDM–MA rubber domains were homogeneously dispersed in the PP matrix, the diameter of domains being between 0.1–1 μm. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1503–1513, 1998
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Thermal, Thermomechanical, and Morphological Properties of Spartium junceum Fiber Reinforced Polypropylene Composites
Article
  • Nov 2006
The composites investigated in this article were polypropylene reinforced with Spanish broom (Spartium junceum) fibers. These fibers were modified with N[-3 Trimethoxysilyl propyl] ethylene diamine (Z6020) or stearic acid, which work as coupling agents between fibers and matrix. This work studied the thermal (differential scanning calorimetry) and thermomechanical (dynamic mechanical thermal) analysis. The surfaces of the composites were characterized by electron microscopy. It was found that silane-treated fiber composites show superior properties compared with the specimens made of pure polypropylene. Microscopic observations correlate with these results.
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Effect of Fiber Content and Chemical Treatment on the Thermal Properties of Spartium junceum Fiber-Reinforced Polypropylene Composites
Article
  • Jun 2008
The thermal and crystallization behavior of PP/Spartium junceum fiber composites were studied by thermogravimetry (TGA) and differential scanning calorimetry (DSC). The surface modification of Spartium junceum fibers was carried out using silane coupling agents in order to improve the interfacial adhesion between the fiber and the matrix. The effects of fiber content and chemical treatment on thermal properties were evaluated. It was found that Spartium junceum fiber degraded before the PP matrix but the thermal stability of the PP/Spartium junceum fiber composites was higher than those of the fiber and the matrix. DSC measurements showed that the incorporation of Spartium junceum fiber caused an increase in the crystallinity of the matrix. These effects have been attributed to the fact that the surfaces of Spartium junceum fibers act as nucleating agents for the crystallization of the polymer, promoting the growth and the formation of transcrystalline regions around the fibers.
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Composite materials based on ligno-cellulosic fibres and thermoplastic matrices (IPP and LDPE)
Article
  • Jul 2009
  • REV ROUM CHIM
Short date palm tree lignocellulosic fibres have been used as a reinforcing phase in commodity thermoplastic matrices (polypropylene-PP and low density polyethylene- LDPE). Both unmodified and compatibilized fibres were used. Compatibilization was carried out with the use of maleic anhydride copolymers. The morphology, thermal and mechanical properties of the ensuing composites were characterized using scanning electron microscopy, differential scanning calorimetry and tensile tests. The reinforcing capability of the unmodified fibres was found to depend on the nature of the matrix and the main parameter governing the composite behaviour was the degree of crystallinity of the matrix. Compatibilization was reported to enhance the mechanical performances for both sets of composites up to a critical amount of compatibilizer beyond which the degree of crystallinity of the matrix decreases.
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New polymeric-coupling agent for polypropylene/wood-flour composites
Article
  • Aug 2007
  • POLYM TEST
The suitability of using polypropylene modified with an organosilane as a coupling agent for polypropylene/wood-flour composites was investigated. The tensile properties, the water-absorption behavior, the thermal degradation properties and the morphology of the composites were analyzed and compared with those of non-coupled composites and of composites coupled with polypropylene modified with maleic anhydride. The coupling agents were prepared in the laboratory and it was verified that the silane showed higher reactivity towards PP chains. The results indicated that the silane-modified polymer increased the interfacial adhesion between the fibers and the polymer matrix and this effect was better than that obtained for the maleated-polypropylene-coupled composites.
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Extrusion and mechanical properties of highly filled cellulose fibre-polypropylene composites
Article
  • Aug 2007
  • COMPOS PART A-APPL S
This study focused on manufacturing of highly filled cellulose fibre–polypropylene composites and evaluation of the mechanical properties of the composites. Cellulose fibre reinforced polypropylene composites with up to 60wt% of fibres with and without coupling agent were manufactured by extrusion. In order to achieve consistent feeding of the fibres into the extruder a pelletization technique was used where the fibres were pressed into pellets. Two commercial grades of cellulose fibres were used in the study, bleached sulfite and bleached kraft fibres. Fibre dimension measurements showed that the pelletization process and extrusion at high fibre loading caused the most severe fibre breakage. Flexural testing showed that increased fibre loading made the composites stiffer but reduced the toughness. Addition of maleic anhydride grafted coupling agent (MAPP) increased the stiffness and strength of the composites significantly. In general, there was no significant difference in the mechanical properties between the composites with kraft and sulfite fibres. An interesting finding was that the flexural modulus and strength of the MAPP modified cellulose fibre–polypropylene composites were not higher than what has previously been reported for wood flour–polyolefin composites. Scanning electron microscopy showed that addition of coupling agent improved the interfacial adhesion between the fibres and polypropylene matrix.
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Wood flour filled PP composites: Compatibilization and adhesion
Article
  • Oct 2007
  • COMPOS SCI TECHNOL
PP/wood flour composites were prepared in a wide range of compositions in an internal mixer at 180°C, 50rpm and 15min. Interfacial adhesion was modified by the introduction of two maleinated polypropylenes (MAPP) with different molecular weights and functionality. Wood content was changed between 0 and 70wt%, while MAPP/wood ratio between 0 and 0.25. Compression molded plates of 1mm thickness were prepared for testing. Structure was characterized by X-ray diffraction and DSC measurements. Interfacial adhesion was estimated quantitatively with model calculations. The results showed that the morphology of the components and that of the composites does not change as a result of compounding and the wood flour used in these experiments does not nucleate PP. The most important structural phenomena determining properties are the orientation of the anisotropic wood flour particles and their aggregation. Both structural phenomena depend on processing conditions and on the dimensions of the product. Much larger improvement could be achieved by the addition of a functionalized polymer in thicker samples than in thin specimens. MAPP has a maximum efficiency at around 0.05–0.10 MAPP/wood ratio in the composites of this study due to the limited surface available for coupling. MAPP with larger molecular weight and smaller functionality proved to be more advantageous in the improvement of composite strength, because it can form larger number of entanglements per molecule than the small molecular weight compound. On the other hand, the smaller molecular weight coupling agent decreases viscosity and improves processability considerably, thus optimization of composition is essential to achieve maximum performance.
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