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Lignin was used only as a fuel until not so long ago, but the research done in the last few years has shown that it is a substance that confers wood its strength and takes the form of granules that may be melted. Thus, lignin was used to produce a material out of which almost anything can be manufactured, from furniture, accessories, toys, plastic cases for electronic devices, and food containers of any shape, to car bodies, and which is known as “liquid wood”. Its properties recommend “liquid wood” as an alternative to all plastic products in the near future, as it is biodegradable and reusable several times, and its properties remain intact. Three types of “liquid wood” are known: Arbofill, Arboblend and Arboform. Whereas Arboform is 100% biodegradable, the other two materials are only partially biodegradable. The following types of “liquid wood” were used: Arbofill Fitchie, Arboblend V2 Nature and Arboform L, V3 Nature. The research described in this paper focuses on the study of microindentation and differential calorimetry. Also, the software package we used enabled us to read both the microhardness values, and the reduced indentation modulus and Young’s modulus.
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Microindentation and differential scanning calorimetry of ‘‘liquid wood’’
Dumitru Nedelcu
a,
, Ciprian Ciofu
a
, Nicoleta Monica Lohan
b
a
‘‘Gheorghe Asachi’’ Technical University of Iasi, Department of Machine Manufacturing Technologies, Blvd. Mangeron, No. 59A, 700050 Iasi, Romania
b
‘‘Gheorghe Asachi’’ Technical University of Iasi, Department of Materials Engineering and Industrial Security, Blvd. Mangeron, No. 59A, 700050 Iasi, Romania
article info
Article history:
Received 20 February 2013
Received in revised form 12 April 2013
Accepted 20 May 2013
Available online 1 June 2013
Keywords:
B. Mechanical properties
D. Thermal analysis
E. Injection moulding
abstract
Lignin was used only as a fuel until not so long ago, but the research done in the last few years has shown
that it is a substance that confers wood its strength and takes the form of granules that may be melted.
Thus, lignin was used to produce a material out of which almost anything can be manufactured, from fur-
niture, accessories, toys, plastic cases for electronic devices, and food containers of any shape, to car
bodies, and which is known as ‘‘liquid wood’’. Its properties recommend ‘‘liquid wood’’ as an alternative
to all plastic products in the near future, as it is biodegradable and reusable several times, and its prop-
erties remain intact. Three types of ‘‘liquid wood’’ are known: Arbofill, Arboblend and Arboform. Whereas
Arboform is 100% biodegradable, the other two materials are only partially biodegradable. The following
types of ‘‘liquid wood’’ were used: Arbofill Fitchie, Arboblend V2 Nature and Arboform L, V3 Nature. The
research described in this paper focuses on the study of microindentation and differential calorimetry.
Also, the software package we used enabled us to read both the microhardness values, and the reduced
indentation modulus and Young’s modulus.
The studied test samples showed the following mean recovery values: 45.9170
l
m for Arbofill Fitchie,
22.2783
l
m for Arboblend V2 Nature and 17.7430
l
m for Arboform L, V3 Nature. These values are in
agreement with the microhardness and modulus of elasticity values. Differential calorimetry research
has shown that Arboblend V2 Nature and Arboform L, V3 Nature suffered two transformations each,
one endothermal and the other exothermal, during which we measured the transformation onset and
completion temperatures, as well as the temperature in the middle of the transformation process. We
also measured the amount of absorbed and dissipated heat, respectively. As far as Arbofill Fitchie is con-
cerned, the DSC diagram showed no temperature-dependent heat flow variation that could suggest a
solid state transformation. We could safely state that the Arbofill Fitchie sample is thermally stable up
to a temperature of 423 K.
Ó2013 Elsevier Ltd. All rights reserved.
1. Introduction
The need to find cheaper and more reliable building materials
has been a major preoccupation for scientists in the last decades,
due to the dramatic decrease of available stock of wood and to
the massive pollution caused by the manufacture of cement, brick,
plastics or other similar products. Almost 40 years ago, American
scientists took the first steps in stopping humanity dependence
on plastic products which, as everyone knows, are made of oil.
Now, the German company Tecnaro say that they managed to
manufacture a product that looks like wood, has a woody struc-
ture, may be cast as plastics and, in addition, is biodegradable
and known as ‘‘liquid wood’’. In fact, the product is extremely
appreciated for this last quality, especially since there is so much
plastic waste that, if spread out, it would cover an area of more
than one million square kilometers! [1].
Liquid wood is a substance that comprises a mixture of cellu-
lose, hemp, fax and lignin used until not so long ago only in the pa-
per making process. Due to its properties, liquid wood may replace
all the current plastic products in the world. Being one of the new-
est green materials, it has an extremely important property: it may
be reused several times without diminishing its properties. Not-
withstanding its price, which is higher than that of polypropylene,
we may safely predict that in a very short time this will be the
most sought after material, since it is biodegradable and does not
pollute the environment. Although it is heavier than plastic, which
is contained in almost all the products that are currently sold
throughout the world, liquid wood has the advantage that it is a
100% natural product, which has no adverse reactions against hu-
man health [2].
As it was considered a mere residue resulted in the paper mak-
ing process, so far lignin has been used only as a fuel. Nevertheless,
the research work conducted these last few years has shown that it
is a substance that confers wood its strength and takes the form of
granules that may be melted. Thus, a special material was obtained
1359-8368/$ - see front matter Ó2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.compositesb.2013.05.024
Corresponding author. Tel./fax: +40 232 217290.
E-mail address: dnedelcu@tcm.tuiasi.ro (D. Nedelcu).
Composites: Part B 55 (2013) 11–15
Contents lists available at SciVerse ScienceDirect
Composites: Part B
journal homepage: www.elsevier.com/locate/compositesb
which may be used to manufacture almost anything, from furni-
ture, accessories, toys, plastic cases for electronic devices, and food
containers of any shape, to car bodies. Arboform may be destroyed
and reused up to ten times without losing its mechanical proper-
ties, like for instance resistance to fire and durability. The only dis-
advantages of liquid wood would be its weight, as it is much
heavier than regular plastic materials, and its manufacture costs,
which are almost double than those of polypropylene, the most
common plastic material. In addition to its positive effects on the
environment, unlike oil-derived plastic, which is considered car-
cinogenic, liquid wood is a product made of natural substances.
The need to find biodegradable building materials has become a
major preoccupation for specialists all over the world, since plastic
waste take between 100 and 1000 years to decompose. Specialists
say that soon Arboform will become the material of the future, as it
will be used in all the fields of activity and will be appreciated at its
true value [3].
The ‘‘liquid wood’’ material was invented by a team of research-
ers from the Fraunhofer Institute for Chemical Technology (ICT) in
Pfinztal (Germany). Three types of liquid wood are known, namely
arbofill, arboblend and arboform [4]. Arboform is 100% biodegrad-
able, whereas Arbofill and Arboblend are only partially biodegrad-
able. The results of the research conducted on microindentation
and differential calorimetry have not yet been known.
Calorimetry has played a very important role in research since
the 20th century, being used is various fields such as: physics,
chemistry, science and materials technology. Its applicability
has also extended to other fields, such as nano-thermodynamics
and bio-thermodynamics [5]. Differential scanning calorimetry
(DSC) measures the amount of heat absorbed/dissipated by a test
sample as compared to a reference value, when the test sample is
subjected to a heating and/or cooling cycle. The calorimetric ef-
fect may be revealed by the temperature- and/or time-dependent
heat flow variation, and its evaluation makes sense when partic-
ular heat flow variations, specific to the various transformations
accompanying temperature variation, occur. These may take the
form of exothermal peaks, which mark increases of the amount
of absorbed heat, or of endothermal minimums, which mark
the dissipation of an amount of heat. These may be attributed
to solid state transformations, like for instance direct and re-
versed martensitic transformation of a shape-memory material
[6]. The calorimetric effect may also refer to an endothermal
stage marking the vitreous transition of an amorphous material
[7,8].
Fig. 1. Average effects of input parameters upon indentation modulus: 1 – Arboform L, V3 Nature; 2 – Arboblend V2 Nature; 3 – Arbofill Fitchie.
12 D. Nedelcu et al. / Composites: Part B 55 (2013) 11–15
2. Experimental part
The technical issue that the project is solving is the obtaining of
‘‘liquid wood’’ benchmarks through monocomponent injection into
molds, a process by means of which products with characteristics
superior to those made of plastics are obtained. ‘‘Liquid wood’’ pel-
lets, which are mainly composed of lignin, discarded during the pa-
per-making process, in combination with cellulose, wood waste
from industrial plants, pellets also known as material under the
name of ‘‘liquid wood’’, are introduced into a bunker where they
are subjected to a hot-air drying process for two hours, after which
the pellets are pneumatically transferred by a pneumatic conveyor,
into the bunker of an injection machine, from where the material
enters an injection cylinder, electrically heated at 150–170 °C (for
Arbofill Fitchie 170 °C, for Arboblend V2 Nature 150 °C and
for Arboform L, V3 Nature – 160 °C), being afterwards injected into
a mold, which is cooled with water at a temperature of 15 °C, the
water being transferred into the mold through a circuit provided
with a cooler.
The advantages of this new technology are: the products ob-
tained have characteristics superior to those of plastic-injected
products, are harder, more flexible and have a better resistance
to shocks; the lack of carcinogens in the product material and their
biodegradability; the multiple recycling of the product obtained
and energy savings due the lower melting temperatures compared
with other plastics [9].
The planning of the experiments was achieved by means of the
Taguchi methodology [10].
The model proposed by Viger and Sisson is also easy to study;
this is the matrix model of the system comprising ‘‘I’’ factors: F
1
,
F
2
,...,F
i
each factor having n
i
levels. Each experiment was con-
ducted three times. The proposed matrix model takes into consid-
eration six technological parameters with two levels. The
coefficients of a type (1) model were determined within the exper-
imental research:
Z
t
¼MþT
top
þt
inj
þt
r
þS
s
þP
inj
þT
mat
þP
inj
T
top
þP
inj
t
inj
þP
inj
t
r
þP
inj
S
s
þP
inj
T
mat
ð1Þ
where M– general average; T
top
– melting temperature (°C); t
inj
injection time (s), t
r
– cooling time (s), S
s
– screw speed (mm), P
inj
– injection pressure (MPa), T
mat
– matrix temperature (°C) [11,12].
The most significant influence on the process is exercised by the
injection pressure followed by the melting temperature and the
matrix temperature (Fig. 1). Screw speed, injection time and cooling
time have less influence on the injection process (Fig. 1).
The DSC experiments were conducted on max. 25 mg fragments
taken from the three Arbofill Fitchie, Arboblend V2 Nature and
Arboform L, V3 Nature test samples. The experiments were carried
out on a type F3 Maia differential scanning calorimeter (DSC) sup-
plied by NETZSCH Company in argon protective environment. Here
are the characteristics of the DSC F3 Maia calorimeter we used:
temperature range: (170...+600) °C; heating rate:
(0.001...100) K/min; cooling rate: (0.001 ...100) K/min; tempera-
ture accuracy: 0.1 K; sensitivity: <1
l
W; enthalpy determination
accuracy: ±0.5%. The device was calibrated on Bi, In, Sn and Zn,
according to standards. The test samples were heated from room
temperature to 423 K, at a heating rate of 1.67 10
1
Ks
1
, then
left to cool freely down to room temperature.
The DSC thermograms recorded during the heating process
were assessed using the Proteus software. Determination of the
critical transformation points: the temperature on transformation
onset (T
s
), temperature in the middle of the transformation process
(T
50
) and temperature on transformation completion (T
f
) were cal-
culated using the tangent line method. The amount of dissipated/
absorbed heat (
D
H) was determined using a sigmoidal baseline.
3. Results and discussion
A Universal UMT-2 (CETR-Center of Tribology, INC., USA) device
was used for the Microindentation Tests. We used a 2 kg sensor
and applied a maximum force of 10 N. We also used diamond tip
Rockwell indenter with a radius of 200
l
m. The capacitive sensor
used measured the vertical indenter displacement.
Thus, Figs. 2–4 show the load diagrams dependent on the verti-
cal indenter displacement. The software package we used enabled
us to read both the microhardness values, and the reduced inden-
tation modulus and Young’s modulus. These values are shown in
Table 1. The table also includes the displacement and recovery val-
ues of the three materials. The research was conducted on three
test samples of each material. The relative density was calculated
as the ratio between the mass density and the reference density
(melt density at 170 °C). The values obtained are as follows: Arbo-
fill Fitchie, 1.08; Arboblend V2 Nature, 1.01; Arboform L, V3 Nat-
ure, 1.06.
The studied test samples showed the following mean recovery
values: 45.9170
l
m for Arbofill Fitchie, 22.2783
l
m for Arboblend
V2 Nature and 17.7430
l
m for Arboform L, V3 nature (see Table 2).
Fig. 2. Microindentation Test on Arbofill Fitchie.
Fig. 3. Microindentation Test on Arboblend V2 Nature.
Fig. 4. Microindentation Test on Arboform L, V3 Nature.
D. Nedelcu et al. / Composites: Part B 55 (2013) 11–15 13
Figs. 5–7 show the calorimetric response of the fragments taken
from the three studied test samples, which were subjected to con-
trolled heating up to a temperature of 423 K.
According to Fig. 4, the DSC Thermogram Recorded during the
Arbofill Fitchie test sample heating reveals no significant deviation
from linearity, which suggests that the test sample undergoes no
solid state transformation.
The DSC curves (heat flow variation) recorded during the heat-
ing of the Arboblend V2 Nature and Arboform L, V3 Nature test
samples are shown in Figs. 4 and 5. As one may notice, two peaks
appear on the DSC thermograms: (i) an endothermal peak occurs
during heating from room temperature to 350 K (I) and (ii) an exo-
thermal peak of greater intensity occurs during heating to temper-
atures exceeding 350 K (II). The endothermal peak occurs within
the same temperature range for both the Arboblend and Arboform
test samples (337–347 K according to the data provided by the Pro-
teus software); the greatest 1.7 K difference was recorded for the
transformation completion temperature T
f
. This deviation from lin-
earity of the heat flow suggests the presence of a solid state endo-
Table 1
Synthetic presentation of the research results.
Parameter
Material Material displacement (
l
m) Recovery (
l
m) Micro hardness (GPa) Indentation modulsus (GPa) Load (N)
Reduced Young’s
Arbofill Fitchie Sp. 1 98.374 42.907 0.079393 0.805 0.826 8.941
Sp. 2 94.205 35.604 0.0811 1.011 0.983 8.942
Sp. 3 110.195 59.24 0.07364 0.591 0.575 8.934
Arboblend V2 Nature Sp. 1 60.051 18.057 0.140298 2.617 2.547 8.965
Sp. 2 63.996 21.793 0.128738 2.429 2.363 8.975
Sp. 3 75.957 26.985 0.110428 1.419 1.38 8.954
Arboform L, V3 Nature Sp. 1 42.575 12.673 0.231877 3.078 2.997 8.970
Sp. 2 46.121 16.005 0.197364 3.541 3.449 8.978
Sp. 3 61.361 24.551 0.150256 1.844 1.794 8.972
Table 2
Summary of data evaluation with proteus software using the tangent method for
critical temperatures determination (T
s
,T
50
and T
f
) and sigmoidal baseline for specific
absorbed/dissipated heat
D
hdetermination.
Sample T
sI
(K)
T
50I
(K)
T
fI
(K)
D
hI
(kJ/kg)
T
sII
(K)
T
50II
(K)
T
fII
(K)
D
hII
(kJ/kg)
Arbofill Fitchie –––– ––––
Arboblend V2
Nature
337.4 341.2 345.4 5.654 359.6 366.3 374.5 19.38
Arboform L, V3
Nature
337.6 341.0 347.1 11.94 363.1 367.6 374.2 28.08
Fig. 5. DSC Thermogram Recorded during Arbofill Fitchie Test Sample Heating.
Fig. 6. DSC Thermogram Recorded during Arboblend V2 Nature Test Sample
Heating.
Fig. 7. DSC Thermogram Recorded during Arboform L, V3 Nature Test Sample
Heating.
14 D. Nedelcu et al. / Composites: Part B 55 (2013) 11–15
thermal transformation occurring upon heating in both test sam-
ples analyzed.
The second solid state transformation (II) is exothermal and, ex-
cept for the transformation onset temperature – T
sII
, the other crit-
ical transformation points occur at about the same temperatures.
This heat flow variation may be attributed to a solid state transfor-
mation occurring with heat generation.
The analysis of the amounts of heat absorbed and dissipated,
respectively, during the two solid state transformations, recorded
for the Arboblend V2 Nature and Arboform L, V3 Nature samples
heated up to a temperature of 423 K, reveals the following
tendencies:
If we compare the amount of heat absorbed by the two analyzed
samples during the first endothermal transformation, recorded
during the heating process, we may easily notice that, in order
for the transformation to take place, the Arboform L, V3 Nature
sample needs twice as much heat as the Arboblend V2 Nature
sample; this assumption is supported by the data included in
Table 1.
The amount of heat dissipated by the Arboblend V2 Nature
sample during exothermal transformation is 1.5 times lower
than the amount of heat absorbed by the Arboform L, V3 Nature
sample during the same transformation.
If we compare the amount of absorbed and dissipated heat by
the same heated material, one may notice that the exothermal
transformation suffered by the Arboblend V2 Nature sample is
greater
D
hI=5.654 whereas
D
hI = 19.38 kJ/kg). The same
ascending tendency is noted for the Arboform L, V3 Nature
sample.
4. Conclusions
Liquid wood is a substance that comprises a mixture of cellu-
lose, hemp, fax and lignin used until not so long ago only in the pa-
per making process. Due to its properties, liquid wood may replace
all the current plastic products in the world.
Notwithstanding its price, which is higher than that of polypro-
pylene, we may safely predict that in a very short time this will be
the most sought after material, since it is biodegradable and does
not pollute the environment. Three types of liquid wood are
known: Arbofill, Arboblend and Arboform. Arboform is 100% biode-
gradable, whereas Arbofill and Arboblend are only partially biode-
gradable. The research was conducted on Arbofill Fitchie,
Arboblend V2 Nature and Arboform L, V3 Nature. The microinden-
tation research revealed following mean recovery values for the
studied materials: 45.9170
l
m for Arbofill Fitchie, 22.2783
l
m
for Arboblend V2 Nature and 17.7430
l
m for Arboform L, V3 Nat-
ure. These recovery values are in agreement with the microhard-
ness and modulus of elasticity values.
During the Arbofill Fitchie sample heating, the DSC diagram
showed no temperature-dependent heat flow variation that could
suggest a solid state transformation. Therefore, we could safely
state that the Arbofill Fitchie sample is thermally stable up to a
temperature of 423 K.
The DSC thermograms recorded during the heating of the Arbo-
blend V2 Nature and Arboform L, V3 Nature samples show two
peaks, one endothermal and the other exothermal, which are
attributed to a series of transformations occurring in the solid
state; the two transformations occur within the same temperature
range for both analyzed samples.
The amount of absorbed/dissipated heat is at least 1.5 times
higher in the Arboform L, V3 Nature than in the Arboblend V2 Nat-
ure sample.
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D. Nedelcu et al. / Composites: Part B 55 (2013) 11–15 15
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The purpose of the present paper is to analyze, both experimentally and theoretically, the behavior of the polymeric biocomposite generically known as “liquid wood”, trademarked as Arbofill. The experimental part refers to the mechanical performance in tension and compression, having as finality the possibility of using “liquid wood” as a material suitable for the rehabilitation of degraded wooden elements in civil structures (ex. use in historical buildings, monuments etc.,). The theoretical part refers to computer simulations regarding the mechanical behavior of “liquid wood” as well as to a theoretical model in the paradigm of motion, which describes the same behavior. This model is based on the hypothesis that “liquid wood” can be assimilated, both structurally and functionally, to a multifractal object, situation in which its entities are described through continuous, non-differentiable curves. Then, descriptions of the behavior of “liquid wood”, both in the Schrödinger-type and in hydrodynamic-type representations at various scale resolutions, become operational. Since in the hydrodynamic-type representation, the constitutive law of “liquid wood” can be highlighted, several operational procedures (Ricatti-type gauge, differential geometry in absolute space etc.,) will allow correlations between the present proposed model and the experimental data. The obtained results, both practical (81% bearing capacity in compression and 36% bearing capacity in tension, compared to control samples) and theoretical (validation of material performance in virtual environment simulations, stresses and strains correlations in a theoretical model) indicate that “liquid wood” could be used in the construction industry, as a potential rehabilitation material, but with more development clearly needed.
... The material of the samples used for texturing is Arboblend V2 Nature, a biopolymer patented by a team of researchers from the Fraunhofer Institute for Chemical Technology (ICT) in Pfinztal (Germany) in collaboration with the company Tecnaro GmbH, showing great potential for use in industrial applications from all fields that use renewable resources and whose content is based on biopolymers, such as polyhydroxyalkanoates (PHAs), polycaprolactone (PCL), polyester (e.g., bio-PET), starch, polylactic acid (PLA), bio-polyolefins (bio-PEs), bio-polyamides (bio-PAs), lignin, natural resins, natural waxes, natural oils, natural fatty acids, cellulose, organic additives and natural reinforcing fibers [22]. The basic properties of the Arboblend V2 Nature material are presented in Table 1 [23], and a number of authors have studied this material both from the point of view of mechanical and thermal properties and have also analyzed its structure [24][25][26][27][28][29]. The modulus of elasticity MPa 2900 2700 2300 ...
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Surface texturing is an engineering technology used in order to improve the surface characteristic of plastic parts obtained by injection molding. Applying this process not only changes the part surface properties, but also its topography. The novel functionalities of plastic products become useful when other materials make contact with the textured surface. Of course, these characteristics may vary depending on the laser positioning, dimensions, and geometry of the texture. The present paper presents the surface characteristics obtained after the laser texturing of the Arboblend V2 Nature biodegradable polymer. Three distinct geometries were studied: hexagonal, square, and triangular, and different behaviors of them were highlighted during surface free energy (SFE) and contact angle (WCA) measurements: a hydrophobic character for square and hexagonal geometry with distilled water as the measure liquid, and a hydrophilic character with diiodomethane as the measure liquid; for triangle geometry, the contact angle measurements were impossible to extract because the drop turns into a flat puddle. Additionally, the friction coefficient varied depending on the geometry texture, with the lowest value being recorded by the sample with hexagonal geometry. The micro-indentation tests highlighted increased surface micro-hardness compared to the basic material. The possibility of use in the practice of textured surfaces is viable; thus, based on the obtained results, there is even the possibility to replace non-biodegradable polymers from different sectors of activity.
... ARBOFORM® materials are especially filled in lignin. They exhibit a thermoplastic behavior [137,138] as well as potentially interesting melt characteristics towards printing. Mechanical, thermal, and rheological properties of typical materials are reported in Table 23. ...
... ARBOFORM® materials are especially filled in lignin. They exhibit a thermoplastic behavior [137,138] as well as potentially interesting melt characteristics towards printing. Mechanical, thermal, and rheological properties of typical materials are reported in Table 23. ...
Chapter
Three-dimensional (3D) printing or additive manufacturing is a technology that has drastically developed in recent years for numerous industrial applications. Among the 3D printing methods, fused deposition modeling requires filaments to generate 3D objects. Currently, the polymers used in this technology are synthetic ones derived from nonrenewable resources such as petroleum. Green polymers (including natural polymers) are a sustainable alternative as they are biodegradable/recyclable, nontoxic, and abundant. However, their implementation in 3D printing remains a challenge. This chapter is focused on the most popular and promising biodegradable polymers from biomass produced by microorganisms or derived from biotechnology for applications of fused deposition modeling. Their thermal, rheological, and mechanical properties are also discussed in detail.
... The Ra parameter of the roughness of the surfaces treated with water jet with abrasive material was made with the HOMMEL TESTER T 500 roughness meter. The biodegradable material Arboblend V2 Nature was used, whose studies on mechanical, thermal and structural properties were carried out by a number of authors according to [20][21][22][23][24][25][26], and which were extremely useful in establishing the research and selection methodology of the parameters of the water cutting process. The cut parts of the two materials are shown in Figure 6. ...
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The main purpose of the technical optimization is to determine the optimal values of the processing parameters in order to increase the processing performance or decrease the processing time. Abrasive material water jet cutting is a processing process whose applicability is increasing in the conditions of the appearance of high-performance equipment. The technical optimization of this machining process aims at determining the distance between the machined material and the cutting head, determining the optimum length of the focusing tube, establishing the optimum machining pressure and determining the optimum amount of abrasive material so as to ensure maximum penetration depth of water jet with abrasive or minimizing surface roughness. During the research, the part subjected to abrasive water jet cutting was obtained by injection from Arboblend V2 Nature. The experiments were carried out according to a complete factorial plan 23, where the parameters on two levels were: water jet pressure, cutting speed and abrasive material flow. The optimization criterion followed was to minimize the standard roughness Ra. The experimental results showed that the parameter flow rate of abrasive material has the greatest influence on the roughness, the highest values of roughness are obtained when using a larger amount of abrasive (300g / min). The lowest value of the roughness of the cut surfaces is obtained for the following process parameters: low water pressure - 100MPa, high cutting speed - 150 mm / min and high flow of abrasive material - 300g / min.
... Comparing the obtained results with those of the Arboblend V2 Nature polymer, an improvement of the hardness is observed by deposition of ceramic layers, since the average value of its hardness is 0.12 GPa, [15]. The behaviour of the tested samples from maximum penetration depth poin of view captured in Figure 3. ...
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This paper aims to present the development of new material with enhanced properties using a biodegradable material such as Arboblend V2 Nature and silver nanoparticles through Physical Vapor Deposition process. Thus, the materials chosen for this study are Arboblend V2 Nature and silver. Arboblend V2 Nature is a thermoplastic material made from byproducts of the wood pulp industry to replace plastic materials made from petroleum. Silver nanoparticles are known to provide antimicrobial properties for surfaces. Physical Vapor Deposition is one of the most used coating methods in the industrial sector. The main goal is to create a benchmark of materials that can be further exploited in a wide variety of applications in areas such as medical, dental, automotive, electronics, and others.
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This review addresses the reconstruction of structural plant components (cellulose, lignin, hemicelluloses) into materials displaying advanced optical properties. The strategies to isolate the main building blocks is discussed, and the effects of fibrillation, fibril alignment, densification, self‐assembly, surface‐patterning, and compositing are presented considering their role in engineering optical performance. Then, we describe the key elements that enable lignocellulosic to be translated into materials that present optical functionality, such as transparency, haze, reflectance, UV‐blocking, luminescence, and structural colors. Mapping the optical landscape that is accessible from lignocellulosics is shown as an essential step toward their utilization in smart devices. Advanced materials built from sustainable resources, including those obtained from industrial or agricultural side streams, demonstrate enormous promise in optoelectronics due to their potentially lower cost, while meeting or even exceeding current demands in performance. We summarize the requirements for the production and application of plant‐based optically functional materials in different smart material applications and conclude the review with a perspective about this active field of knowledge. This article is protected by copyright. All rights reserved
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Calorimetry is an effective analytical tool to characterize the glass transition and phase transitions under confinement. Calorimetry offers a broad dynamic range regarding heating and cooling rates, including isothermal and temperature modulated operation. Today 12 orders of magnitude in scanning rate can be covered by combining different types of calorimeters. The broad dynamic range, comparable to dielectric spectroscopy, is especially of interest for the study of kinetically controlled processes like crystallization or glass transition. Accuracy of calorimetric measurements is not very high. Commonly it does not reach 0.1% and often accuracy is only a few percent. Nevertheless, calorimetry can reach high sensitivity and reproducibility. Both are of particular interest for the study of confined systems. Low addenda heat capacity chip calorimeters are capable to measure the step in heat capacity at the glass transition in nanometer thin films. The good reproducibility is used for the study of glass forming materials confined by nanometer sized structures, like porous glasses, semicrystalline structures, nanocomposites, phase separated block copolymers, etc. Calorimetry allows also for the frequency dependent measurement of complex heat capacity in a frequency range covering several orders of magnitude. Here I exclusively consider calorimetry and its application to glass transition in confined materials. In most cases calorimetry reveals only a weak dependence of the glass transition temperature on confinement as long as the confining dimensions are above 10 nm. Why these findings contradict many other studies applying other techniques to similar systems is still an unsolved problem of glass transition in confinement.
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The calorimetric response of a martensitic Cu-Zn-Al-Fe shape memory alloy (SMA) was evaluated during second heating, up to 453-K, with different rates ranging between 1.67-10-2 and 1.67×10-1 K s-1, performed on a differential scanning calorimeter (DSC). Heating rate (HR) variation caused a marked change of the endothermic peak aspect, which was observed on the DSC thermograms recorded during second heating and associated with the martensite reversion to parent phase. The particularities of the DSC thermograms obtained at different HR values were analysed and critical transformation temperatures of martensite reversion were determined by means of integral method. The influence of HR was corroborated with morphological changes of martensite plates. The results prove that there is an obvious relationship between HR values and the morphology of martensite plates, obtained after post-heating holding and cooling. The term of `heating rate memory effect` was introduced to define the influence of temperature variation rate during heating on the martensitic structure obtained after subsequent cooling.
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Differential ac-nanocalorimetric studies of a structural phase transition in the vicinity of 306 K in tetragonal lysozyme crystals have been carried out. It was found that the anomalies in the temperature dependences of heat capacity of the crystals look like gimel-type anomalies. On the other hand, a pronounced temperature hysteresis has been observed at temperature cycling. The variation of experimental conditions such as relative humidity, frequency of the AC heat flow applied to the crystal of the order of 10 Hz, and heating rate seem not to affect the temperature of the anomaly in C-p(T). Crown Copyright (c) 2012 Published by Elsevier B.V. All rights reserved.
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This paper deals with the issue of robust motion control of a clamp-cylinder for injection moulding machines driven by a pair of speed-controlled fixed displacement pumps. As a fundamental step prior to tracking controller design, a feedback control system is suggested by implementing a position control loop in parallel with a system pressure control loop. A discrete-time sliding mode control scheme is developed for enhancing the tracking performance under inherent nonlinearities. Consequently, a significant reduction in tracking error is achieved for both position and pressure control applications.
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Calorimetry and thermodynamic studies have long been playing a very important role in the research fields of fundamental science and technology. Some topics and examples of thermodynamics studies are given, and the details are explained on the basis of the present author’s experience, focusing attention to application of adiabatic calorimetry and thermodynamics to solve critical problems in materials science: (1) condensed gas calorimetry and third law entropy, (2) phase transition and polymorphism in simple molecular crystals, (3) incommensurate phase transitions, (4) particle size effects on the phase transitions in ferroelectric/ferroelastic crystals, (5) relaxor ferroelectrics and multi-ferroics, and some other topics in materials science and technology.
Aspecte ale formarii canelurilor exterioare prin deformare plastic la rece utilizand metoda Taguchi
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Nedelcu D, Pruteanu O. Aspecte ale formarii canelurilor exterioare prin deformare plastic la rece utilizand metoda Taguchi. Chisinau: Tehnica-Info Publishing House; 2000. p. 243-261.
Injectarea materialelor plastice. Oradea: Imprimeria de Vest Publishing House
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Seres I. Injectarea materialelor plastice. Oradea: Imprimeria de Vest Publishing House; 1996. p. 314-25.