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Review
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A Review: Natural Fiber Composites Selectionin View of Mechanical, Light Weight, andEconomic Properties
Furqan Ahmad, Heung Soap Choi, Myung Kyun Park*
In this study, the properties and application of natural fiber composites in automobile industriesare discussed. Natural fibers are replacing the synthetic fibers in the various parts of automobilesdue to their lightweight, low-cost, and environmental aspects. For centuries, natural fibers havebeen used for making baskets, clothing, and ropes. Now the trend is changing and natural fibers
such as: jute, hemp, flax, andsisal fibers are making theirways especially into thecomponents of automobiles.Comparisons of material in-dices for beam and panelstructures were made toinvestigate the possibilityof using natural fiber com-posites instead of conven-tional and non-conventionalmaterials.F. Ahmad, M. K. ParkDepartment of Mechanical Engineering, MYongin, KoreaE-mail: [email protected]. S. ChoiDepartment of Mechanical and Design EngUniversity, Sejong, KoreaF. AhmadDepartment of Civil and Environmental EnDaejeon, Korea
� 2014 WILEY-VCH Verlag GmbH & Co. KGaA, WeinMacromol. Mater. Eng. 2015, 300, 10–24
1. Introduction
Over the last decade, natural fiber reinforced polymer
composites have been embraced by European automobile
makers especially in themanufacturing of door panels, seat
backs, headliners, package trays, dashboards, and trunk
liners.Nowthe trendhas reached tootherparts of theworld
like the United States and Asian countries, particularly in
Japan. Thenumberof automobiles thathavebeenproduced
yongji University,
ineering, Hongik
gineering, KAIST,
heim wileyonlinelib
in the last century has rapidly increased due to the
modernizationof the transportation systemsandeconomic
development inAsia, Europe, andUnited State. Automotive
industries throughout the world are continuously trying
to optimize cost over quality in order to remain competitive
in the market. The application of natural fiber composites
is rapidly increasing in the automobile sector[1�6] at an
annual growth rate of above 20% because of its low
density, reasonably acceptable strength and day-by-day
lowering cost, non-abrasiveness and safe handling, ease of
separation, enhanced energy recovery, CO2 neutrality,
biodegradability, recyclable properties, etc. Furthermore,
these fiber based composites have the potential of
contributing greatly to the automotive manufacturer’s
final goal constituting 30% weight reduction and a cost
reduction of 20%.[7�12]
Recyclability or bio-degradability of natural fiber com-
posite products after a useful life make them more
important and enforce the automotive manufacturers to
increase the application of natural fibers. If biodegradable
DOI: 10.1002/mame.201400089rary.com
A Review: Natural Fiber Composites Selection . . .
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fibers were chosen to substitute many of the existing
composite parts, one may reduce great difficulties of
disposing of these products.[13] According to Directive
2000/53/EC, the European Community requires member
countries to reuse and recover at least 95% by 2015 for all
end-of-life vehicles.[14] Lucintel’s report[15] forecasts that
the natural fiber composite materials market will grow to
531.3 million dollars in 2016.
Demand from automotive companies for materials with
noise abatement capabilities as well as increased fuel
efficiency by reducing the weight has increased[16] due to
the fact that natural fiber composites possess excellent
sound-absorbingcapabilities, aremoreshatter resistantand
have more efficient energy management characteristics
than glass and the demand for natural fiber composites has
increased in the market.[17] Demand for natural fibers in
plastic composites are forecast to grow at a 15�20% in
automobile application and 50% or more in selected
building application.[18] Natural fiber-based automobile
parts such as various panels, trim parts, and brake shoes
are attractive to the automotive industry because theyhave
reduced the weight of parts by more than 10% and have
also brought the cost down by as much as 5%.[19�20]
Natural fibers such as flax, hemp, and jute can be used as
reinforcement for thermoset or thermoplastic polymers
instead of synthetic fibers. Thermoplasticmaterial current-
ly dominates as matrixes for natural fibers are polypropyl-
ene and polyethylene, while thermosets, such as phenolic
and polyesters, are common matrixes. Both thermosets
and thermoplastics are attractive as matrix materials for
composites as a result of large numbers of components
being involved such as base resin, curing agents, catalysts,
flowing agents, and hardeners that make the formulation
complicated in thermoset composites. The composite
materials are thermo-chemically cured to a highly cross-
linked, three-dimensional network structure. These cross-
linked structures are highly solvent resistant, tough, and
creep resistant. Generally, thermoplastics offer many
advantages over thermoset polymers. One advantage is
their low processing cost. Another is design flexibility, ease
ofmolding complex parts, and recyclability. Thermoplastic
compositesareflexible, tough, andexhibit goodmechanical
properties.[21�23]
Although there are many benefits, natural fiber compo-
sites also have several drawbacks, which effect their
utilization in the automobile industry such as higher
moisture absorption, low temperature limitations, microbe
infection, inferiorfireresistance, lowermechanicalproperties
and durability, variation in quality, and pricefluctuationdue
to seasonal harvest conditions, and the difficulty of using
established manufacturing practices when compared to
synthetic composites.[24�26] Many researchers are working
on these issues and paying special attention to improve the
quality of natural fibers by surface treatments for enhanced
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fiber/matrix interface bonding properties.[27,28] In addition,
natural fiber composites have a positive economic and
environmental outlook, and their ability to uniquely meet
human needs worldwide, natural composites are showing a
good potential for use in the automobile industry.
Natural fiber composites have acceptable mechanical
properties such as elongation, ultimate breaking force,
flexural properties, impact strength, acoustic absorption,
suitability for processing, and crash behavior, which also
increases its demand for automobile components. Eastern
Germany’s Trabant (1950�1990)was the first production car
built fromnaturalfibers. Itwasequippedwithachassismade
of cotton embedded in a polyester matrix. BMW has been
using renewablenatural fibermaterials since the early1990s
in the3, 5, and7Seriesmodelswithupto24kg. In2001,BMW
used 4000 metric tons of natural fibers in the 3 series alone
with a blend of 80% flax and 20% sisal for increased strength
and impact resistance. Themainapplication is in the interior
door linings and paneling. Wood fibers are also used to
enclose the rear side of seat backrests and cotton fibers are
utilized as a sound-proofing material.
Up until recently, car manufacturers have been being
used thermoplastics reinforced by mineral products or
fiberglass. So nowadays, many companies are making
various parts of automobiles from various kinds of natural
fiber composites.[29] Volvo has started to use soya-based
foam linings in its C70 and V70models for their seats with
natural fibers. To improve the quality of noise reduction
they have also produced a cellulose-based cargo floor tray.
In Western Europe, the yearly production of cars is up to
16 million vehicles that equate to an including usage of
80 000�160000 tons of natural fibers per year. German
automobile companies like Daimler-Chrysler are continu-
ing to lead the way, having a global natural fiber initiative
programthat benefits thirdnationsbydevelopingproducts
made from natural fibers. One of the recent developments
within the automotive industry has been the release of the
Lotus Eco Elise. Another development was announced in
2008 at the EcoInnovAsia 2008 event held in Bangkok,
Thailand, related to the Mazda 5. In this application, the
manufacturer is using polylactic acid (PLA) in the interior
consoles along with kenaf and PLA in the seat covers.[30]
In this paper, an attempthas beenmade to explain about
the natural fibers and their application in automobile
industry. Natural fiber types and their corresponding
properties are also summarized and discussed.
2. Natural Fibers
Natural fibers are continuous filaments or discrete elongat-
ed pieces, similar to pieces of thread and they can be
spun into filaments, thread, or rope. They can be used as a
componentof compositematerials. Theycanalsobematted
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Figure 1. Source of natural fibers.
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F. Ahmad, H. S. Choi, A. Ullah, M. K. Park
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into sheets tomake products such as paper or felt. There are
of two types of fiber: natural fiber and man-made or
synthetic fiber. All fibers, which come from the nature are
mainly divided into three main sources; animals, vegeta-
bles, andminerals. And they are classed as natural fibers as
shown in Figure 1. Some of the natural fibers like vegetable
fibers are obtained from the various parts of vegetable
plants and theyareprovidedbynature in ready-made form.
It includes protein fibers such as wool and silk, cellulose
fibers such as cotton and linen, and mineral fiber
asbestos.[31�34] Some of the important natural fibers used
as reinforcement in composites are listedwith their species
and origins in Table 1.
2.1. Chemical Composition
Plant fibers are composed of cellulose, lignin, or similar
compounds and animal fibers are composed of protein.
Table 1. List of important natural fibers.
Fiber source Species Origin
Abaca Musa textiles Leaf
Bamboo (>1 250 species) Grass
Banana Musa indica Leaf
Coir Cocos nucifera Fruit
Cotton Gossypium sp. Seed
Curau�a Ananas erectifolius Leaf
Flax Linum usitatissimum Stem
Hemp Cannabis sativa Stem
Henequen Agave fourcroydes Leaf
Jute Corchorus capsularis Stem
Kenaf Hibiscus cannabinus Stem
Oil Elaeis guineensis Fruit
Pineapple Ananus comosus Leaf
Ramie Boehmeria nivea Stem
Sisal Agave sisilana Leaf
Wood (>10 000 species) Stem
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Pectin is a collective name for heteropolysaccharides and
they provide flexibility to plants. Waxes make up the last
part of fibers and they consist of different types of alcohols.
Table 2presents the chemical composition of some selected
natural fibers.[35�37]
2.2. Chemical Treatments
Natural fibers are not totally free of problems even though
they have the comparative advantage of low cost and low
density over otherfibers. Asnatural fibershave strongpolar
characteristics, which may cause a problem of incompati-
bility inbondingwithmostof thepolymermatrices, surface
chemical treatment processes increase the cost of natural
fibers but can enhance the property of interface adhesion
between the fiber and matrix, and also decrease the water
absorption of fibers. Therefore, chemical treatments can be
considered as modifying the properties of natural fibers.
Someof the chemical treatments fornaturalfibers are listed
below:[38�46]
1
2015
H &
Alkaline treatment.
2
Silane treatment.3
Acetylation of natural fibers.4
Benzoylation treatment.5
Acrylation and acrylonitrile grafting.6
Maleated coupling agents.7
Permanganate treatment.8
Peroxide treatment.9
Isocyanate treatment.10
Etherification of natural fibers.11
Acrylation,maleic anhydride, and titanate treatmentofnatural fibers.
12
Plasma treatment.13
Sodium chlorite treatment of natural fibers.2.3. Physical and Mechanical Properties
Tensile strength and Young’s modulus of fibers increase by
increasing cellulose.[47] The micro-fibrillar angle deter-
mines thestiffnessof thefibers. Plantfibersaremoreductile
if themicro-fibrils have a spiral orientation to the fiber axis.
If the micro-fibrils are printed parallel to the fiber axis,
the fibers will be rigid, inflexible, and have high tensile
strength. Table 3 presents the important physical and
mechanical properties of natural and synthetic fibers,
which have been adapted from several sources.[48�54]
2.4. Manufacturing Processes
For automobile manufacturers, it is commonly accepted
that the natural fiber molding process consumes less
energy than that of fiber-glass and induces less wear and
tear damage onmachinery, cutting production costs by up
, 300, 10–24
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Table 2. Chemical composition of selected natural fibers.
Fiber
name
Cellulose
[wt%]
Lignin
[wt%]
Hemi-cellulose
[wt%]
Pectin
[wt%]
Wax
[wt%]
Moisture
[wt%]
Ash
[wt%]
Micro-fibrillar
angle [8] Refs.
Abaca 56�63 7�9 20�25 � 3 � � 20�25 [8]
Bamboo 26�43 1�31 30 � � 9.16 � � [40]
Banana 83 5 � � � 10.71 � 11�12 [40]
Coir 37 42 � � � 11.36 � 30.45 [37]
Cotton 82.7�91 � 3 � 0.6 7.85�8.5 � � [37]
Curau�a 73.6 7.5 9.9 � � � � � [40]
Flax 64.1�71.9 2�2.2 64.1�71.9 1.8�2.3 1.7 8�1.2 � 5�10 [36]
Hemp 70.2�74.4 3.7�5.7 17.9�22.4 0.9 0.8 6.2�1.2 0.8 2�6.2 [40]
Jute 61�71.5 12�13 17.9�22.4 0.2 0.5 12.5�13.7 0.5�2 8 [12]
Kenaf 45�57 21.5 8�13 0.6 0.8 6.2�12 2�5 2�6.2 [37]
Rachis 42.75 26 � � � � � 28�37 [40]
Ramie 68.6�91 0.4�0.7 5�14.7 1.9 � � � 69�83 [37]
Rice husk 38�45 � 12�20 � � � 20 � [40]
Sea grass 57 5 38 10 � � � � [40]
Sisal 78 8 10 � 2 11 1 � [37]
Table 3. Physical and mechanical properties of selected natural and synthetic fibers.
Fiber
name
Density
[g cm�3]
Diameter
[mm]
Tensile
strength
[MPa]
Specific
strength
[S/r]
Tensile
modulus
[GPa]
Specific
modulus
[E/r]
Elongation
at break
[%] Refs.
Abaca 1.5 � 400 267 12 8 3�10 [8]
Bamboo 1.1 240�330 500 454 35.91 32.6 1.40 [40]
Banana 1.35 50�250 600 444 17.85 13.2 3.36 [8,37]
Coconut 1.15 100�450 500 435 2.5 2.17 20 [40]
Coir 1.2 � 175 146 4�6 3.3�5 30 [37]
Cotton 1.6 � 287�597 179�373 5.5�12.6 3.44�7.9 7�8 [37]
Curau�a 1.4 170 158�729 113�521 � � 5 [40]
Flax 1.5 � 800�1 500 535�1 000 27.6�80 18.4�53 1.2�3.2 [12,36]
Hemp 1.48 � 550�900 372�608 70 47.3 2�4 [36,37]
Jute 1.46 40�350 393�800 269�548 10-30 6.85-20.6 1.5�1.8 [36,37]
Kenaf 1.45 70�250 930 641 53 36.55 1.6 [37]
Ramie 1.5 50 220�938 147�625 44�128 29.3�85 2�3.8 [37]
Sisal 1.45 50�300 530�640 366�441 9.4�22 6.5�15.2 3�7 [37]
Softwood 1.5 � 1 000 667 40 26.67 4.4 [40]
Man-made fibers (for comparison)
E-glass 2.55 <17 3 400 1 333 73 28.63 3.4 [8,36]
S-glass 2.5 � 4 580 1 832 85 34 4.6 [40]
Aramid 1.44 11.9 3 000 1916.67 124 86.11 2.5 [8,9]
HS carbon 1.82 8.2 2 550 1 401 200 109.9 1.3 [36]
A Review: Natural Fiber Composites Selection . . .
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Macromol. Mater. Eng. 2015, 300, 10–24
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Figure 2. Cost per weight comparison between natural fibers and synthetic fibers.
www.mme-journal.de
F. Ahmad, H. S. Choi, A. Ullah, M. K. Park
14
to 30%. Manufacturing techniques
designed and used for other fiber-rein-
forced polymer composites are also used
to fabricate natural fiber composites.
Even though manufacturing techniques
like compression molding, injection
molding, pressmolding, pultrusion, resin
transfer molding, and sheet molding
compound (SMC) are already well devel-
oped, it is still not clear whether that
these techniques are suitable for the
fabrication of natural fiber composites
with a desirable quality because of some
ambiguity of weather-dependent me-
chanical, thermal, and structural proper-
ties of the natural fibers. One of the
reasons is that natural fiber needs
chemical treatment, which is used to compensate its
incompatible bonding effect at the interface between fiber
and matrix.[55�58]
Figure 3. Tensile modulus versus cost per volume (rCm) fornatural fiber, synthetic fiber, natural fiber composite, andsynthetic fiber composite.
3. A Comparison of Natural Fibers withSynthetic Fibers
Due to the high degree of variability inherent in natural
fibers and their testing, various values of Young’s modulus
and tensile strength properties of natural fibers are
available in literature, so the maximum values of these
propertieswere taken for the purpose of comparison.[59�65]
Bast fibers have the best mechanical properties for
automobile applications; of those, flax offers the best
potential combination of low cost, light weight, and high
strength and stiffness as compared to other bast fibers. The
most commonly used natural fiber is jute, but it is not as
strong or stiff as flax fibers. Kim et al.[66] found that natural
fibers in thermoset composites dissipate energy at lower
levels of stress and higher strain than glass-reinforced
composites. In the case of thermoplasticmatrices, the effect
on energy dissipation of natural fibers is highly dependent
on resin properties.
Fibers like flax, kenaf, jute, and hemp have less density
andgoodmechanical properties, so theyarewell suitable as
reinforcement for polymer composites, which are used as
tensile loadbearingproperties. A comparisonof the cost per
weight (Cm, $ kg�1) between natural fibers and glass fiber is
shown in Figure 2. The values of the cost per weight were
obtained from literature[67�69] and theprice rangeoffiber is
shown in Figure 2. As compared to glass fiber, the natural
fibers are generally cheaper in cost. The cost of glass fiber is
found to be lower than other synthetic fibers (carbon,
graphite, aramid, boron, etc.) andhigher thannaturalfibers.
As compared to natural fibers, the glass fiber is fairly heavy
fiber due to its high density of 2.5�2.6 g cm�3 and is not as
Macromol. Mater. Eng.
� 2014 WILEY-VCH Verlag Gmb
environmental friendly as natural fibers.[67�69] The cost per
volume (rCm, $ m�3) versus tensile modulus and tensile
strength graphs for natural fibers, synthetic fibers, natural
fiber composites, and synthetic fiber composites are shown
in Figure 3 and 4, respectively.
Figure 5 shows the range of Young’s modulus (E) anddensity (r) for some well-known natural fibers, synthetic
fibers, natural fiber composites, and synthetic fiber
composites. Data for members of a particular family
(natural fibers, synthetic fibers, natural fiber composites,
and natural fiber composites) of material cluster together
and are enclosed by an envelope of different colors. Natural
fibers have a lower density compared to synthetic fibers
and good tensile modulus. Natural fiber composites also
havea lowerdensity compared to synthetic fiber composite
and metallic materials. Tensile strength versus density
graph for natural fibers, synthetic fibers, natural fiber
2015, 300, 10–24
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Figure 4. Tensile strength versus cost per volume (rCm) fornatural fiber, synthetic fiber, natural fiber composite, andsynthetic fiber composite.
Figure 6. Tensile strength versus density diagram for naturalfibers, synthetic fibers, natural fiber composites, and syntheticfiber composites.
A Review: Natural Fiber Composites Selection . . .
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composites, and synthetic fiber composites is shown in
Figure 6. Flax/PP and Hemp/PP composites have high
tensile moduli and tensile strengths as compared to glass
fiber composite. The material indices E1/2/r and E1/3/r are
plotted (dashed lines) in Figure 5. These lines are referred to
as material selection guidelines on which all materials
satisfy an objective function, which is to be maximized or
minimized by the higher value of material index for
selectedmaterials.[120] All thematerials that lie on adashed
line of constant E1/2/r perform equally well as a light, stiff
beam; those above the line are better, those below, worse.
The increasing directions of material indices S1/2/r and
Figure 5. Tensile modulus versus density diagram for naturalfiber, synthetic fiber, natural fiber composite, and syntheticfiber composite.
Macromol. Mater. Eng
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S2/3/r are plotted in Figure 6. All the materials on the same
guideline having the same material index can meet the
requirements of materials to be optimized as a light and
strong beam or a panel under bending load.
4. Materials Selection
Comparisons were made between natural fiber/PP compo-
sites and other materials for the selection of suitable
material for beam and panel structures of automobiles.
For this purpose, materials were compared using their
material index or performance index. Natalia et al.[70]
present some results for material selection for beam
combined with structural design and optimization.
They made comparisons of the material index of natural
fiber/PP composite (Vf¼ 40%) with other materials for
beam structure by using Young’s moduli of materials. In
this study, Young’s moduli and tensile strength were used
for the material index of natural fiber/PP composite
(Vf¼ 30%) and othermaterials to investigate the possibility
of using natural fiber composites for beam and panel
structures of automobile components, which can replace
some conventional metal and synthetic fiber composite
structures. The mechanical properties and cost data of
the materials were obtained from literature.[16,71�74]
The material index is E1/2/r or S2/3/r for a light and stiff
or light and strong beam under bending load, E1/2/(rCm)or S2/3/(rCm) for a stiff and cheap or strong and cheap
beam under bending load, E1/3/r or S1/2/r for a light
and stiff or light and strong panel under bending load, and
E1/3/(rCm) or S1/2/(rCm) for a stiff and cheap or strong
and cheap panel, where Cm is cost per unit weight ($ kg�1)
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F. Ahmad, H. S. Choi, A. Ullah, M. K. Park
16
of the material. For rCm, it has a unit of cost per volume
($m�3). Figure 7 and 8 show a comparison of the stiffness
limited design based material index and the strength
limited design based material index of natural fiber/PP
composite andother syntheticmaterials forbeamstructure
under bending load. The larger the stiffness and strength
with lower density and cost, the better the material to be
used as the light, stiff and strong, or stiff, strong and cheap
beam. Through a comparison of stiffness and strength
material index for a light, stiff, and strong beam (Figure 7) a
carbon/epoxy fiber composite as the best material for the
desired beam structure. Wrought magnesium alloy and
wrought aluminum alloy are the next candidates for light
and stiff beam and wrought magnesium alloy and carbon
steel for light and strong beam structure. From natural
fiber/PP composites, hemp fiber/PP composite is more
suitable for lightandstiff or lightandstrongbeamstructure
as compared to glass fiber/PP composite.
If the cost ofmaterial is included for considerationvia the
material index for a stiff and cheap or strong and cheap
beamstructureunder abending load (Figure8), then carbon
Figure 7. Material index for a light and stiff (left) or light and strong (rbending load.
Figure 8. Material index for a stiff and cheap (left) or strong and chunder bending load.
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steel is the best choice as a material for beam structural
components. However, as the next candidates, non-
conventional natural fiber composites can be considered:
composites/PP reinforced with flax, hemp, and kenaf
fibers are recommended for the location where the stiff
and cheap beam structure is required. While for the
location where the strong and cheap beam structures are
required, the hemp/PP and flax/PP composites are recom-
mended as compared to the carbon/epoxy and glass fiber/
PP composite. Comparisons of stiffness and strength
material indices for panel structure of natural fiber/PP
composite with those materials are shown in Figure 9
and 10. Carbon/epoxy composite has the highest value in
the comparison of stiffness and strength material indices
for a light and stiff or light and strong panel structures are
shown in Figure 9. The next candidates for those material
indices are wrought magnesium alloy and hemp fiber/PP
composite. Material indices including cost of the materials
for stiff and cheap or strong and cheap panel are shown in
Figure 10. For a stiff panel with minimum cost, the natural
fiber/PP composites are more suitable than other candi-
ight) beam under
eap (right) beam
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H & Co. KGaA, Weinhe
dates while for strong panel with mini-
mum cost carbon steel is the best choice
and thenext candidates arenatural fiber/
PP composites instead of the glass fiber/
PP or carbon/epoxy composite.
This case study shows that natural
fiber composites have superior price
competitiveness with performance opti-
mizations. If the cost and weight of the
materials are considered, then the natu-
ral fiber composites aremore suitable for
applications in automobile components
than glass fiber composites. Natural fiber
composites have yet greater potential to
replace competing conventional materi-
als such as glass fiber composites in the
automobile industry.
5. Challenges
Currently, glass fibers take globally more
than95%of themarket for reinforcement
fibers in the composites industry while
natural fiber composites are limited
in applications to the interior parts of
automobiles due to their relatively lower
mechanical properties andweak interface
characteristics between fiber and matrix,
but these properties are being improved
through new coming technology for
surface treatment, additives, and coat-
ings.Naturalfibershavesomeadvantages
im www.MaterialsViews.com
Figure 9. Material index for a light and stiff (left) or light and strong (right) panel underbending load.
Figure 10. Material index for a stiff and cheap (left) or strong and cheap (right) panelunder bending load.
A Review: Natural Fiber Composites Selection . . .
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over glass fiber in some aspects: production of natural fiber
has a lower impact on the environment as compared to
glass fiber production; fiber content in natural fiber
composites are generally higher than that of glass fiber
composite for equivalent performance, natural fiber
composite are environmentally friendly and reduce more
pollutingbasedpolymer content; light-weightnatural fiber
composites improve fuel efficiency and reduce emissions
when used for automobile components and end of life
incineration of natural fibers results in recovered energy
and carbon credits.[75,76] Besides all these advantages,
natural fibers are still facing some challenges to improve
their properties in moisture absorption, fiber modification,
fire resistance, durability, and variability in quality which
depend upon their locational weather conditions. These
challenging areas are considered as follows.
5.1. Moisture Absorption
Generally, all natural fibers are hydrophilic in nature and
they tend to absorb water even from the air. On the other
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hand, glass fibers are hydrophobic in
nature and they are moisture resistant.
Such a hydrophilic nature of natural
fibers can be a drawback, which makes
them less competitive compared to glass
fibers. When in wet conditions natural
fiber composites absorb moisture from
a moist atmosphere resulting in fiber
swelling or interface disbands that make
the natural fiber composite limited to
interior parts of the automobile.[77] Singh
and Gupta[78] found that the strength of
a sisal/polyester composite was 13�31%
lower when fully immersed than at 95%
RH. Dhakal et al.[79] studied the effects of
water absorption on the mechanical
properties of hemp fiber reinforced un-
saturated polyester composites and
they compared the tensile and flexural
properties of water immersed hemp
composite specimens with dry hemp
specimens. They found that the tensile
and flexural properties of hemp fiber
composite specimens decreased with an
increase of percentage uptake moisture
content.
Singh et al.[80] studied the effects of
hydrothermal and weathering condi-
tions on the physical and mechanical
properties of the jute fiber composite.
They found some dimensional change
of jute composites as a function of
exposure time under the different hu-
midity conditions. Increasing humidity levels, theweight
and thickness increased by the swelling of jute fibers.
Giridhar et al.[81] compared the moisture absorption
behaviors of sisal and jute fiber composites with epoxy
matrix under water immersion conditions and found
that sisal fibers exhibited higher moisture absorption
levels in their composite form compared with jute fiber
composites. Fibers with high cellulose content tend to
have a higher fiber volume fraction, which increased the
percentage of moisture uptake. Improving the poor
environmental and dimensional stability of natural fiber
is an effective way to enhance the mechanical properties
of these fibers.
5.2. Fiber Modification
Fiber modification is required to reduce the moisture
absorption capability of natural fibers. The most common
methods for reducing moisture absorption capability are
alkali treatment and acetylation of natural fibers. Alkaline
treatment ormercerization is one of the best used chemical
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F. Ahmad, H. S. Choi, A. Ullah, M. K. Park
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treatments for natural fibers. Alkali treatment is usually
donewithKOH, LiOH, orNaOH,which reduce the hydrogen
bondingof celluloseand increase theamountofamorphous
cellulose at the expense of crystalline cellulose. Alkali
solution not only affects cellulosic components inside the
plant fiber but also affect the non-cellulosic components
such as hemicellulose, lignin, and pectin. Hemicellulose is
the most hydrophilic part of natural fiber structures so
alkali treatmentwithNaOH, reduces theabilityof thefibers
to absorb moisture.[82,83] The chemical reaction formula,
which taking place during this treatment is shown below
Fiber� OHþNaOH ! fiber� O�NaþH2O
Acetylation of natural fibers is a well-known esterifica-
tion method, which can reduce the hygroscopic nature of
natural fibers and increase the dimensional stability of
natural composites. Acetylation is generally used in
surface treatments of fiber for use in fiber-reinforced
composites.[84,85] Bledzki et al. modified the surface of
flax fiber by the acetylation method and noted that due
to acetylation, the flax fiber surface morphology, and
moisture resistance properties improved. Tensile and
flexural strengths of composites were found to increase
with increasing acetylation degree up to 18% and then
decreased.[86] The chemical reaction formula of acetic
anhydride with fiber is shown as.
Fiber� OHþ CH3 � Cð¼ OÞ � O� Cð¼ OÞ � CH3
! fiber� OCOCH3 þ CH3COOH
Some negative aspects of the alkali treatment process
may include the high pH values, high surfactant content,
polluted wastewater, and the chemo-mechanical degrada-
tion of cellulose fibers. Alkali-treated fibers are more
effective in lowering moisture absorption; the enzyme-
treated fibers produce less polluted wastewater. Fiber
modification enhances the commercial value of natural
fibers.
5.3. Fire Resistance
Generally,naturalfibercompositeshavepoorfireresistance,
which is a major drawback of natural fiber composites for
certain automobile and other industrial applicationswhere
inflammability and safety are considered to be important
factors. This drawback of poor fire resistance poses new
challenges for natural fibers to compete with synthetic
fibers. Natural fibers are non-thermoplastic and they have a
lower decomposition temperature compared to their glass
transition and/or melting temperatures.
Natural fibers are composed primarily of cellulose,
hemicellulose, lignin, waxes, and inorganic, nonflammable
substances as shown in Table 3. A high content of cellulose
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increases the flammability of natural fiber. The cellulose
decomposes at a temperature range of 260�350 8C, while
hemicellulose decomposes at a lower temperature range
between 200 and 260 8C and forms more noncombustible
gases and less tar than cellulose. Lignin starts decomposing
from about 160 8C and continues to decompose until about
400 8C. Lignin contributes more to char formation than
either cellulose or hemicellulose. Manfredi et al.[87] showed
the importance of lignin in the thermal decomposition of
flax, jute, and sisal fiber and found that the thermal
degradation behavior of jute fiber and sisal fiber were
similar because they have almost the same weight
percentage of lignin, whereas the flax has less percentage
of lignin and it degrades at higher temperature. Lower
lignincontent inflaxcontributed toahigherdecomposition
temperature but resulted in a lower oxidation resistance.
Differences in chemical compositions of the natural fibers
cause thevariations in their characteristics inflammability.
Natural fibers with high cellulose content are more
flammable than those natural fibers which have low
cellulose and high hemicelluloses contents and char
formation is generally better with higher lignin con-
tent.[88�91] Besides the chemical composition, fine fiber
structure and orientation of natural fibers also play major
roles in the flammability of natural fibers. Horrocks
compared the effects of heat and flame on the physical
andchemical behaviorofnaturalfiberswithotherfibers.[92]
Fire resistance of natural fiber composites has received
less attention and only a small number of studies are
available in literature on fire performance of natural fiber
composites. It is still a challenge for researchers to find
other ways or methods to enhance the fire resistance of
natural fibers. Natural fibers with high lignin content, low
crystallinity, and high orientation angle generally have a
high fire resistance. Plant and protein base fibers are
another option for reducing the flammability of fiber
reinforcement. There are, however, other factors such as
mechanical properties to consider when selecting natural
fibers as the reinforcement of composite materials.[93,94]
Thermal degradation and flame resistance of natural fiber
composites and glass fiber composites with a modar and
polyester matrix are shown in Figure 11.
Three natural fibers (flax, jute and sisal) show different
behavior against fire. The natural fiber composites con-
taining flax and sisal fibers cause a slow growing fire for a
longer duration and jute fiber composite causes a quickly
growing fire for a short duration. The glass fiber composite
shows a minor fire risk as expected. With the change of
matrix, the behavior against fire changed.
5.4. Durability
Durability of the natural fiber composite under various
humidity, hygrothermal, and weathering conditions and
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Figure 11. Fire risk of the natural fiber composites and glass fibercomposites.[89] (Reproduced with proper authorization andcopyright permission from the M. Wladyka-Przybylak).
A Review: Natural Fiber Composites Selection . . .
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their effects on physical andmechanical properties are also
one of the major concerns. Durability of natural fibers is
closely related to the resistance of fiber to external and
internal effects, which cause the reduction in strength and
life of natural fiber. Unfortunately, data related to the
durability of natural fibers is limited, which needs to be
addressed.
Flexural and tensile properties of the natural fibers
changewith environmental conditions, such as the change
inhumidityandtimeexposure.[95�100] Singhetal.[80] found
that the tensile strength of jute fiber composite was
decreased between 23 and 52% and flexural strength
up to 11�57% at 95% RH compared to fresh jute fiber
composite. Tensile and flexural strengths were found to
have decreased more at 95% RH, 50 8C than 95% RH,
room temperature. Some black spot and white patches,
which are fungal hyphae were also found on jute fiber
composite under a microscope. Fungus was developed on
the surface of flax fibers just after 3 d of exposure to
moisture environment.[26] The use of proper coatings and
certain types of fiber modification seemed to delay the
effects of weathering.
5.5. Variability
The variability of natural fiber causes variation in
mechanical properties of fiber, which creates problems in
the design or quality assurance aspect of the natural fiber
reinforced composite. Due to the typical large variation in
measured mechanical properties of flax fibers, they are
often used only for low-grade composite applications.
Various cross-sectional diameters of fibers may lead to a
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variation in the mechanical properties of natural
fibers.[101,102]
There are many factors, which cause variation in the
quality and size of natural fiber: geometric location of
field, crop variety, harvest seed quality and density, soil
quality, fertilizer used, harvesting time, and climate
and weather conditions. Some other variations like
extraction processing methods, damage cured during
handling and processing, and the differences in drying
processes can induce further variation in the end-use
product. Variation in price is also found along with
variability in the quality of natural fibers of the plants at
the time of their harvest. The best way to overcome these
drawbacks is to grow many types of fibers in different
regions to avoid local shortfalls.
6. The Application of NFC in Automobiles
Recently, natural fibers like jute, hemp, flax, and sisal have
been a part of high-tech development and began to remove
their negligence. Automobile industries as listed in Table 4
have got interested in new biomaterials, which can be
partially decomposable or recyclable for the current global
trendsof theenvironmentalprotectionanddevelopmentof
sustainable technology. The application of natural fiber
composites has increased and is gaining preference over
glass fiber and carbon fiber due to their low-cost and low-
weight characteristics. European-based natural fiber com-
posite molders such as Dr€axlmaier Group and Faurecia
supply automobile interior parts such as headliners, side
and back walls, seat backs, and rear deck trays to GM,
Audi, and Volvo.[103,104] Figure 12 shows several parts,
which can be fabricated using natural fiber composites.
The life cycle assessment (LCA) of a fiber is an important
tool, which is used to evaluate the environmental impact
associated with that fiber for its entire life cycle. It is
used to compare the two or more fibers and evaluate
which one is more durable and preferable under certain
environmental conditions. Vaidyanathan et al.[105] pre-
sented a scheme for the construction of a hybrid natural
fiber polymeric composite (H-NFPC) sandwich molding
system thatwould form the basic technology of composite
molded automobile body panels and skins. The proposed
sandwich construction has a central core covered with
two outer skins. The price of automobile body panels
can be further reduced by replacing metal parts with
synthetic fibers but these fibers do not deal with the
problem of pollution from the sustainable environment
friendly material concept, which the automobile industry
is facing. Natural fibers deal with both problems and can
reduce both the price and pollution.
W€otzel et al.[106] evaluated the LCA of automobile side
panels fabricated from hemp fibers reinforced composite
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Table 4. Applications of NFC in automobile.
Manufacturer Model Application of NFC Refs.
Audi A2,A3, A4, A4,
Avant, A6, A6
Seat backs, side and back door panel, boot lining,
hat rack, and spare tire lining
[111]
Avant, A8, Roadster,
Coupe
BMW 3, 5, and 7 series
and others
Door panels, headliner panel, boot lining, seat backs,
noise insulation panels molded foot, and well linings
[111,115]
Citroen C5 Interior door paneling [111]
Daimler/Chrysler A, C, E, and S-Class,
EvoBus (exterior)
Door panels, windshield, dashboard, business table,
and pillar cover panel
[111,112]
Ford Mondeo CD 162, Focus Door panels, B-pillar, and boot liner [111]
Lotus Eco Elise Body panels, spoiler, seats, and interior carpets [111,116]
Mercedes-Benz Trucks Internal engine cover, engine insulation, sun visor,
interior insulation, bumper, wheel box, and roof cover
[111�114]
Opel GM Astra, Vectra, Zafira Headliner panel, door panels, pillar cover panel,
and instrument panel
[111]
Peugeot New model 406 Seat backs and parcel shelf [111]
Renault Clio, Twingo Rear parcel shelf [111]
Rover Rover 2000 and others Insulation and rear storage shelf/panel [111]
Saab � Door panels and seat backs [111]
SEAT � Body panels, Spoiler, Seats, Interior carp, etc. [111]
TOYOTA Brevis, Harrier,
Celsior, RAUM
Door panels, seat backs, and spare tire cover [111,117]
Volkswagen Golf, Passat, Variant,
Bora, Fox, Polo
Door panel, seat back, boot lid finish panel,
and boot liner
[111]
Volvo C70, V70 Seat padding, natural foams, and cargo floor tray [111]
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F. Ahmad, H. S. Choi, A. Ullah, M. K. Park
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and acrylonitrile butadiene styrene (ABS) composite
materials. The weight of the automobile side panel was
820 g resulting in weight reduction of up to 27% as
compared to ABS fiber composites of 1 125 g due to high
volume fraction and lower density of hemp fibers. W€otzel’s
study clearly supports the justification for the substitution
Figure 12. Applications of NFC in automobile.
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� 2014 WILEY-VCH Verlag Gmb
of ABS with hemp fiber composite for automobile side
panels. Schmidt and Beyer[107] also evaluated the LCA and
recommended the substitution of the glass fibers with
hemp fibers for automobile insulation panels. A weight
reduction of 26% was obtained by replacing glass fiber
insulation panels (3 100 g) with hemp fiber insulation
panels (2 600 g). Joshia et al.[75] reviewed and the studies
by W€otzel et al. and Schmidt et al. and showed that the
natural fiber composites were more environmentally
friendly than glass fiber composite as a candidate for
automobile applications. As natural fibers during their
growth period absorb CO2 and their specific volume is
higher than that of glass fiber, which increased the
volume fractions of natural fiber and reduced the cost of
polymers and due to their light weight, natural fiber
composites can reduce the weight of automobile parts
with an environmentally friendly image.[108�110]
The most structural applications of natural fiber
composites are the load floors of sport utility vehicles,
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Volkswagen Touareg, Porsche Cayenne, and were recently
introduced in the Audi Q7. These parts consist of sandwich
construction of expanded polypropylene foam covered on
each side with natural fiber/polypropylene composites
skins with an area density of 1 400 gm�2 and topped with
PET carpet. Each load floor weighing 3.5 kg and measuring
950mm by 870mm is produced in a single molding
fabrication cycle.
Flax/polypropylene underbody composite components
have replaced theglassfiber reinforcedplastic components
in Mercedes-Benz A-Class, where almost 20.8 kg of natural
fiber are used in A-Class for more than 20 components as
shown in Figure 13a. Under floor protection trim of A-Class
made from banana fiber reinforced composites a biopoly-
mer isbeingused for thefirst time in large-scale production
atMercedes-Benz in theengine coveron thenewMercedes-
BenzA-Class (petrol engineM270). The floor of the luggage
compartment consists ofa cardboardhoneycombstructure
and wood serves as the base for door paneling. The textile
seat covers consist of 25% pure sheep’s wool. In the new
Mercedes-Benz B-Class, the natural fibers largely comprise
coconut and wood fibers as well as honeycomb cardboard,
Figure 13. a) NFC in Mercedes-Benz A-Class,[112,113] b) NFC in Mercedes-Bc) Eco Elise with interior parts,[116] d) Toyota RAUM spare tire cover,[117]
i-MiEV door panel.[118] (using with copyright permission from the co
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which are used in combination with various polymer
materials for series production. By using the natural fiber,
21 componentswith a total weight of 19.8 kg are produced
for B-Class. The cardboard honeycomb structure is used
for the floor of the luggage compartment and charcoal
coke serves as an activated charcoal filter for fuel tank
ventilation. Mercedes-Benz C-Class was equipped with a
sisal-reinforced rear panel shelf. The wood and cotton
fibers in combination with various polymers are being
predominantly used in the production of the new C-Class.
By combining sisal and cotton, the share of natural
fibers in the component increased to more than 70% by
weight. 17 kg of natural fiber were used in C-Class for the
manufacturing of 27 components as shown in Figure 13b.
Natural fiber is also used in fuel tanks for ventilation and
olive coke serves as an activated charcoal filter. This open-
pored material absorbs hydrocarbon emissions, and the
filter self-regenerates during vehicle operation. Natural
fiber materials are also used for the production of fabric
seat upholstery of the new Mercedes-Benz C-Class, which
contains 15% pure sheep’s wool. Sheep’s wool has
significant comfort advantages over synthetic fibers and
enz C-Class,[112,113]
and e) Mitsubishimpanies).
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it not only has very good electrostatic
properties, but is also better at absorbing
moisture and has a positive effect on
climatic seating comfort at high
temperatures.
For the first time in 1994, Mercedes-
Benz introduced door panels using jute-
based natural fiber composites for the E-
Class car. Flax, hemp, sisal, wool, and
other natural fibers were used to make
components of the Mercedes-Benz E-
Class. For thenewE-Class, 44components
were made from natural fibers with an
overall weight of around 21 kg. By using
natural fibers, the overall weight of the
components has been reduced by 34%
comparedwith the precedingmodel. The
floor of the boot features a honeycomb
cardboard structure, and Mercedes engi-
neers have also used a rawmaterial from
nature to ventilate the fuel tank: olive
coke serves as anactivated charcoal filter.
This open-pored material absorbs hydro-
carbon emissions, and the filter is self-
regenerating during vehicle operation.
Naturalmaterials also play an important
part in the production of the fabric seat
upholstery for the new E-Class, which
contains 25% pure sheep’s wool. Wool
has significant comfort advantages over
synthetic fibers: it not only has very
good electrostatic properties, but is also
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F. Ahmad, H. S. Choi, A. Ullah, M. K. Park
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better at absorbing moisture and has a positive effect on
climatic seating comfort in high temperatures.
27 parts of Mercedes-Benz S-Class are made from
natural fiber composites. The S-Class has 43 kg of
natural fiber components: Door panels and pillar inners,
the head liner, rear cargo shelf, and trunk components
and thermal insulation. For fuel tank ventilation, the
olive coke is used, which serves as an activated charcoal
filter.
At first, natural fibers were used for standard exterior
components in the Mercedes-Benz Travego travel coach
and is equipped with flax reinforced engine and trans-
mission covers. Exterior components posed interesting
issues for the manufacturers, as in these applications
the components must function as a protective cover for
the important parts of the vehicle and as a result the
component must be able to resist a more aggressive
environment (as compared to the interior applications)
being exposed to both weathering effects and also
chipping caused by debris making contact with the
external surface. The benefits of this usage of natural
fiber for exterior parts are an approximately 10% weight
reduction and a cost reduction of about 5% for the engine
and transmission cover. A door panel from the new
Mercedes-Benz M-Class and R-Class platforms highlights
the mold ability characteristics of natural fiber. The back
side attachments shown in dark color are preloaded on the
tool and bonded to the natural fiber composite during
molding without resorting to adhesives, a key factor in
labor and material savings.
BMW has been using natural fiber composite since the
early1990s in its 3, 5, and7 seriesmodelswithup to24 kgof
renewable materials being utilized. BMW used 4000 tons
of natural fibers in the BMW M3 series alone in 2001. The
blend combination of 80% flax with 20% sisal is used for
increasing the strength and impact resistance. The main
application was interior door linings and paneling. Wood
fibers were also used to enclose the rear side of the seat
backrests and cotton fibers were utilized as a sound
proofing material. The natural fiber reinforced plastic
(NFRP) by a press molding process for the fabrication of
flax/PP composite was used for the inner board of the
door panel of a BMW M3 Series. Bast natural fibers
were used for the door panel of the BMW M5 Series. In
the BMW M7 Series, flax and sisal fibers are used for the
interior door linings and panels and cotton fibers were
incorporated in the soundproofing material, wool fibers in
the upholstery, and wood fibers were used to enclose the
rear side of the seat backrests.[115]
The Lotus ECO Elise body panels were made from hemp-
fiber-reinforced polyester composite replacing standard
glass/polyester composite. Hemp fibers visible in the bold,
unpainted bumper-to-spoiler stripe make a striking eco-
contrast to the silver metallic finish. The seats, door panels,
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shifter boot, horn pad, and other interior surfaces were
upholstered with special undyed eco-wool and the carpet
was woven from sisal fiber as shown in Figure 13c.[116]
Toyota has been using increasingly more natural fibers
in their components since 1999, in the range of their
vehicles such as in the Celsior, Brevis, and Harrier. For
door trim, kenaf fibers along with polypropylene are
used and manufactured at Toyota’s Indonesian produc-
tion facility. Toyota has manufactured the first mass
produced 100% (by weight) natural automotive product
namely the RAUM spare tire cover.[117] Toyota RAUM
used kenaf fiber and polylatic acid (PLA) for the cover
board of the spare tire as shown in Figure 13d. Toyota is
also using natural fiber from kenaf plants in the door and
package tray trim base materials. Bamboo fiber and
polybuthylene succinate (PBS) composite was used for
the inner board of trunk door panel of Mitsubishi i-MiEV
as shown in Figure 13e.[118]
A NFRP board processed by press molding from flax
fiber and PP is used for the inner instrumental panel of
the Smart Fortwo Coupe. In 2000, Audi launched the A2
mid-range car, which was the first mass-produced vehicle
with an all-aluminum body. To supplement the weight
reduction afforded by the all-aluminum body, door trim
panels were made of polyurethane reinforced with a
mixed flax/sisal mat. This resulted in extremely low
density and the panels also exhibited high dimensional
stability. Natural fiber composites rear cargo area load
floor of the Porsche Cayenne is composed of structural
layers of natural fiber composites surrounding an
expanded polypropylene foam core and covered with
carpet cloth. All materials are co-molded in a single, low-
pressure press cycle. The natural fiber composite floors
are also used on the Volkswagen Touareg and new
Audi Q7 vehicles, built on the same platform. The door
panels of the Ford Mondeo were manufactured by kenaf
reinforced polypropylene composites.[119]
7. Conclusion
This study has shown the application of natural fiber and
replacement of synthetic fibers in the automobile industry.
In the last decade, the use of natural fibers has been
significantly increased for industrial applications especial-
ly in the automobile industry. Natural fiber composites are
replacing the conventional glass fiber composites in the
automobile industry because of their light weight and
lower cost. Natural fiber composites recently had a great
renewed interest for a variety of reasons in the automobile
industry for increased fuel efficiency, reduced the cost, ease
of production, lower density and weight, and an increased
awareness on the subject of recycling and the impact of
materials on the environment have also played a major
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role in the adoption of natural fiber composites. For a
good composite, it is required to have good interface
characteristics between fiber and matrix for the transfer
of the stress load through interfaces. With great benefits
natural fibers also have some problems, such as incompati-
bility with synthetic polymers, a lack of dimensional
stability, and problems with process and quality. Natural
fiber composites are used in a variety of interior and
exterior parts of automobiles. Current research for a
greater understanding of natural fiber composites will
also contribute to a greater interest and uptake in these
natural fiber-based composite systems by an industry that
will continue to lead to more and more products entering
the marketplace in the future. Comparisons of material
indices show that carbon steel is the best candidate for
the bending loaded beam and panel structures. For stiff
and cheap or strong and cheap beam and panel structures,
the hemp/PP and flax/PP composites are recommended
as compared to the carbon/epoxy and glass fiber/PP
composite.
Acknowledgements: I would like to thanks and appreciate Mr.Aleem Ullah for his valuable help to complete this article.
Received: March 11, 2014; Revised: May 28, 2014; Publishedonline: September 2, 2014; DOI: 10.1002/mame.201400089
Keywords: automobile industry; natural fiber composite
[1] B. C. Suddell, W. J. Evans, D. H. Isaac, A. Crosky, FourthInternational Symposium on Natural Polymers and Compo-sites, Sao Pedro, Brazil 2002.
[2] D. D. Andjelkovic, D. A. Culkin, R. Loza, M. J. Sumner, 9thAnnual Automotive Composites Conference & Exhibition,Michigan, USA September, 2009.
[3] D. S. Aparecido Paulo, C. G. Joao, A. Jay,M. Glauco, 8th AnnualAutomotive Composites Conference & Exhibition, Michigan,USA, September 2008.
[4] A. Ashori, Bioresour. Technol. 2008, 99, 11.[5] C. B. Suddell, J. E. William, Natural Fiber Composites in
Automotive Applications, CRC Press, Florida 2005.[6] A. Le~ao, R. Rowell, N. Tavares, Applications of Natural Fibers
in Automotive Industry in Brazil � Thermoforming Process,Plenum Press, New York 1998.
[7] D. Chandramohan,1 K. Marimuthu, Int. J. Res. Rev. Appl. Sci.2011, 8, 2.
[8] J. Biagiotti, D. Puglia, J. M. Kenny, J. Nat. Fibers 2008, 1, 2.[9] J. Biagiotti, D. Puglia, J. M. Kenny, J. Nat. Fibers 2008, 1, 3.
[10] M. Thiruchitrambalam, A. Athijayamani, S. Sathiyamurthy,A. S. A. Thaheer, J. Nat. Fibers 2010, 7, 4.
[11] A. N. Netravali, H. Xiaosong, K. Mizuta, Adv. Compos. Mater.2012, 16, 4.
[12] J. Summerscales, N. Dissanayake, A. Virk, W. Hall, Compo-sites: Part A: Appl. Sci. Manuf. 2010, 41, 10.
Macromol. Mater. Eng
� 2014 WILEY-VCH Verlag Gmwww.MaterialsViews.com
[13] A. K. Mohanty, M. Misra, G. Hinrichsen, Macromol. Mater.Eng. 2000, 276�277, 1.
[14] European-Commission, Directive 2000/53/EC of the Europe-an Parliament and of the Council of 18 September. 2000, onEnd-of-Life Vehicles, Union OJotE; 2000. p. 9.
[15] Natural Fiber Composites Market Trend and Forecast2011�2016: Trend, Forecast and Opportunity Analysis.
[16] P. Wambua, J. Ivens, I. Verpoest, Compos. Sci. Technol., 2003,63, 9.
[17] U. G. K. Wegst, Ph. D. Thesis, University of Cambridge, UK1996.
[18] A. Ticolau, T. Aravinthan, F. Cardona, A Review of CurrentDevelopment in Natural Fiber Composites for Structural andInfrastructure Applications, University of Southern Queens-land, Toowoomba 2010, p. SREC2010-F1-5.
[19] M. Karus, M. Kamp, D. Lohmeyer, Study of Markets and PriceSituation of Natural Fibres (Germany and EU), Nova Institute,Germany 2000.
[20] R. Kozlowski, M. Muzyczek, B. Mieleniak, J. Nat. Fibers 2008,1, 1.
[21] O. A. Khondker, U. S. Ishiaku, A. Nakai, H. Hamada,Composites: Part A: Appl. Sci. Manuf. 2006, 37, 12.
[22] J. Holbery, D. Houston, J. Miner. Met. Mater. Soc. 2006, 58, 11.[23] M. Bhowmick, S. Mukhopadhyay, R. Alagirusamy, Text. Prog.
2012, 44, 2.[24] A. Athijayamani, M. Thiruchitrambalam, U. Natarajan, B.
Pazhanivel, Mater. Sci. Eng. A 2009, 517, 1.[25] E. Y. Ishidi, I. K. Adamu, E. G. Kolawale, K. O. Sunmonu, M. K.
Yakubu, J. Thermoplast. Compos. Mater. 2011, 24, 6.[26] A. Stamboulis, C. A. Baillie, S. K. Garkhail, H. G. H. Melick, T.
Peijs, Appl. Compos. Mater. 2000, 7, 5.[27] A. Valadez-Gonzaleza, J. M. Cervantes-Uc, R. Olayo, P. J.
Herrera-Franco, Composites Part B: Eng. 1999, 30, 3.[28] M. Rokbi, H. Osmani, A. Imad, N. Benseddiq, Proc. Eng. 2011,
10.[29] J. W. McAuley, Environ. Sci. Technol. 2003, 37, 23.[30] A. M. Foisal, M. A. Ali, S. K. Byung, I. S. Jong, J. Korean Soc.
Compos. Mater. 2009, 22, 4.[31] www.gov.mb.ca/agriculture/crops/, 1999.[32] http://www.tifac.org.in/news/jute.htm.[33] A. K. Mohanty, M. Misra, G. Hinrichsen, Macromol. Mater.
Eng. 2000, 276�277, 1.[34] W. S. Beckwith, J. SAMPE, 2008, 44, 3.[35] A. K. Mohanty, M. Misra, G. Hinrichsen, Macromol. Mater.
Eng. 2001, 276.[36] R. M. Rowell, A. R. Sanadi, D. F. Caulfield, R. E. Jacobsen, in:
Utilization of Natural Fibers in Plastic Composite: Problemsand Opportunities. Lignocellulosic-Plastic Composites, (Eds:A. L. Leao, F. X. Carvalho, E. Frollini), USP and UNESP, Brazil1997.
[37] K. Rakesh, O. Sangeeta, S. Aparna, Pelagia Res. Libr. 2011, 2, 4.[38] N. P. G. Suardana, P. Yingjun, J. L. Kyoo, Mater. Phys. Mech.
2011, 11.[39] M. S. Huda, T. D. Lawrence, Ind. Eng. Chem. Res. 2005, 44.[40] M. S. Huda, L. T. Drzal, A. K. Mohanty, M. Misra, Compos. Sci.
Technol. 2006, 66.[41] N. Birgitha, MS Thesis, Lulea University of Technology,
Sweden 2007.
[42] L. Xue, G. L. Tabil, S. Panigrahi, J. Polym. Environ. 2007, 15.[43] K. O. Reddy, K. R. N. Reddy, J. Zhang, J. Zhang, A. V. Rajulu, J.
Nat. Fibers 2013, 10, 3.
[44] S. Kalia, B. S. Kaith, I. Kaur, Polym. Eng. Sci. 2009, 49, 7.
[45] M. J. John, R. D. Anandjiwala, Polym. Compos. 2008, 29, 2.
. 2015, 300, 10–24
bH & Co. KGaA, Weinheim 23
www.mme-journal.de
F. Ahmad, H. S. Choi, A. Ullah, M. K. Park
24
[46] T. Kre�ze, S. Iskra�c,M. S. Smole, S. K. Karin, S. Strnad, D. Fakin, J.Nat. Fibers 2008, 2, 3.
[47] A. K. Bledzki, J. Gasssan, Prog. Polym. Sci. 1999, 24, 2.[48] P. A. Fowler, J. M. Hughes, R. M. Elias, J. Sci. Food Agric.
2006, 86.[49] R. Malkapuram, V. Kumar, Y. S. Negi, J. Reinforced Plast.
Compos. 2009, 28, 10.[50] K. G. Satyanarayana, G. G. C. Arizaga, F.Wypych, Prog. Polym.
Sci. 2009, 34.[51] M. C. Symington, W. M. Banks, O. D. West, R. A. Pethrick, J.
Compos. Mater. 2009, 43, 9.[52] T. P. Sathishkumar, P. Navaneethakrishnan, S. Shankar, R.
Rajasekar, N. Rajini, J. Reinforced Plast. Compos. 2013, 32, 19.[53] A. K. B. Ledzki, S. Reihmane, J. Gassan, J. Appl. Polym. Sci.
1996, 59.[54] M. Feughelman, Mechanical Properties and Structure of
Alpha-Keratin Fibres: Wool, Human Hair and Related Fibres,University of New South Wales Press, Sydney 1997.
[55] J. Holberry, D. Houston, J. Mater. 2006, 58, 11.[56] T. Nishimura, Presented at SusCompNet 7 Meeting, Universi-
ty of Bath, UK, October 11, 2004.[57] X. Peng, M. Fan, J. Hartley, M. Al-Zubaidy, J. Compos. Mater.
2012, 46, 2.[58] K. Oksman, J. Reinforced Plast. Compos. 2001, 20, 7.[59] M. A. Fuqua, S. Huo, C. A. Ulven, Polym. Rev. 2012, 52, 3.[60] P. J. Herrera-Franco, A. Valadez-Gonz�alez, Composites Part B:
Eng. 2005, 36.[61] A. E. Correia, S.M. Torres,M. E. O. Alexandre, K. C. Gomes, N. P.
Barbosa, S. D. E. Barros, Mater. Sci. Forum 2013, 758.[62] M. E. H. Bourahli, H. Osmani, J. Nat. Fibers 2013, 10, 3.[63] H. D. Mueller, A. Krobjilowski, J. Ind. Text. 2003, 33, 2.[64] N. Chand, R. Joshi, J. Nat. Fibers 2010, 7, 2.[65] K. Ramanaiah, A. V. R. Prasad, K. H. C. Reddy, Int. J. Polym.
Anal. Charact. 2011, 16, 7.[66] W. Kim, A. Argento, E. Lee, C. Flanigan, D. Houston, A. Harris,
D. F. Mielewski, J. Compos. Mater. 2011, 46, 9.[67] S. W. Beckwith, Compos. Fabrication 2003, 12.[68] A. K. Ray, S. Mondal, S. K. Das, P. Ramachandrarao, J. Mater.
Sci. 2005, 40, 19.[69] D. B. Dittenber, H. V. S. G. Rao, Composites Part A: Appl. Sci.
Manuf. 2012, 43, 8.[70] S. E. Natalia, G. K. Kirill, L. S. Jan, Mater. Des. 2002, 23.[71] M. Zampaloni, F. Pourboghrat, S. A. Yankovich, B. N. Rodgers,
J. Moore, L. T. Drzal, A. K. Mohanty, M.Misra, Composites PartA: Appl. Sci. Manuf. 2007, 38, 6.
[72] N. J. Lee, J. Jang, Composites Part A: Appl. Sci. Manuf. 1999,30, 6.
[73] www.MatWeb.com.[74] www.io.tudelft.nl/research/dfs/idemat/.[75] S. V. Joshia, L. T. Drzal, A. K. Mohanty, S. Arora, Composites
Part A: Appl. Sci. Manuf. 2004, 35, 3.[76] M. K. Ryszard, M. T. Maria, M. Malgorzata, B. B. Jorge, Mol.
Cryst. Liquid Cryst. 2012, 556, 1.[77] V. K. Thakur, A. S. Singha, Polym. -Plast. Technol. Eng. 2010,
49, 7.[78] B. Singh, M. Gupta, in Natural Fibers. Biopolymers, and
Biocomposites, Eds., A. K. Mohanty, M. Misra, L. T. Drzal),Taylor & Francis, Boca Raton 2005.
[79] H. N. Dhakal, Z. Y. Zhang, M. O. W. Richardson, Compos. Sci.Technol. 2007, 67, 7.
[80] B. Singh, M. Gupta, A. Verma, Compos. Sci. Technol. 2000, 60.[81] J. Giridhar, K. Rao, J. Reinforced Plast. Compos. 1986, 5.[82] A. K. Mohanty, M. Misra, L. T. Drzal, Compos. Interfaces 2001,
8, 5.
Macromol. Mater. Eng.
� 2014 WILEY-VCH Verlag Gmb
[83] P.Wongsriraksa, K. Togashi, A. Nakai, H. Hamada,Adv.Mech.Eng. 2013, 2013.
[84] R. Kumar, S. Obrai, A. Sharma, Pelagia Res. Libr., Der Chem.Sin. 2011, 2, 4.
[85] D. S. Kumar, R. Punyamurthy, B. Bennehalli, S. C. Venkate-shappa, Int. J. Agric. Sci. 2012, 4, 4.
[86] A. K. Bledzki, A. A. Mamun, M. Lucka-Gabor, V. S. Gutowski,Polym. Lett. 2008, 2, 6.
[87] L. B. Manfredi, E. S. Rodr�ıguez, M. Wladyka-Przybylak, A.V�azquez, Polym. Degrad. Stabil. 2006, 91.
[88] S. Chapple, R. Anandjiwala, J. Thermoplast. Compos. Mater.2010, 23.
[89] R. Kozowski, W. P. Maria, Polym. Adv. Technol. 2008, 19.[90] L. B. Manfredi, E. Rodr�ıguez, M. Wladyka-Przybylak, A.
V�azquez, Compos. Interfaces 2010, 17, 5.[91] T. D. Ngo, M. T. Ton-That, W. Hu, J. SAMPE 2013, 49, 3.[92] A. R. Horrocks, J. Soc. Dyers Colour. 1983, 99, 7.[93] T. Wittek, T. Tanimoto, Polym. Lett. 2008, 2, 11.[94] S. Bhattacharjee, H. S. Muhammad, A. I. Muhammed, M. M.
Ahtashom, Asaduzzaman, Y. M. Muhammed, Int. J. Mater.Sci. Appl. 2013, 2, 5.
[95] B. N. Dash, A. K. Rana, H. K. Mishra, S. K. Nayak, S. S. Tripathy,J. Appl. Polym. Sci. 2000, 78, 9.
[96] S. Joseph, Z. Oommen, S. Thomas, J. Appl. Polym. Sci. 2006,100, 3.
[97] G. Mehta, A. K. Mohanty, L. T. Drzal, D. P. Kamdem, M. Misra,J. Polym. Environ. 2006, 14.
[98] L. Yan, N. Chouw, K. Jayaraman, Composites Part B: Eng.2014, 56.
[99] G. C. Davies, D. M. Bruce, J. Text. Res. 1998, 68, 9.[100] P. K. Bajpai, D.Meena, S. Vatsa, I. Singh, J. Nat. Fibers 2013, 10, 3.[101] M. Aslan, G. C. Carrasco, B. F. S�rensen, B. Madsen, J. Mater.
Sci. 2011, 46.[102] J. L. Thomason, J. Carruthers, J. Kelly, G. Johnson, Compos. Sci.
Technol. 2011, 71.[103] J. Holberry, D. Houston, J. Mater. 2006, 58.[104] H. Kim, B. Swiecki, J. Cregger, The Bio-Based Materials
Automotive Value Chain, Center for Automotive Research,2012.
[105] H. Vaidyanathan, P. Murty, S. Eswara, SAE Technical Paper,2011.
[106] K. W€otzel, R. Wirth, M. Flake, Die Angew. Makromol. Chem.1999, 272.
[107] W. Schmidt, H. Beyer, SAE Technical Paper, 1998.[108] A. D. L. Rosa, G. Cozzo, A. Latteri, G. Mancini, A. Recca, G.
Cicala, Chem. Eng. Trans. 2013, 32.[109] M. Schmehl, J. Mussig, U. Sch€onfeld, H. B. V. Buttlar, J. Polym.
Environ. 2008, 16.[110] C. Santulli, M. Janssen, G. Jeronimidis, J. Mater. Sci. 2005, 40.[111] K. Hill, The Bio-Based Materials Automotive Value Chain,
Center for Automotive Research, 2012.[112] www.daimler.com.[113] www.mercedes-benz.com.[114] G. Cicala, G. Cristaldi, G. Recca, A. Latteri, Woven Fabric
Engineering, Sciyo, Croatia 2004.[115] raw. Renewable, in. materials, production. automotive,
from. Information, B. M. W. the, Group, 2005.[116] www.lotuscars.com.[117] www.toyota.co.jp.[118] www.mitsubishi-motors.com.[119] A. K.Mohanty,M.Misra, L. T. Drzal,Natural Fibers, Biopolymers,
and Biocomposites, CRC Press Taylor & Francis, Florida 2005.[120] M. F. Ashby, Materials Selection in Mechanical Design
Elsevier, Burlington, MA, USA 2011.
2015, 300, 10–24
H & Co. KGaA, Weinheim www.MaterialsViews.com