Jute composite and its applications
S. Das
Indian Jute Industries’ Research Association
17 Taratola Road, Kolkata-700088, India
1
Background:
Composite materials from man-made fibres (i.e. glass fibre, carbon fibre etc.) are
already available as products for consumer and industrial uses. A relatively newer
concept is to consider natural fibres as a reinforcing material. Stringent
environmental legislation and consumer awareness has forced industries to
support long term sustainable growth and develop new technology based on
renewable feedstock that are independent of fossil fuels. As the current status
quo, the main reinforcement for the composite industry is glass fibres; 22.3 million
tons (metric) are produced globally on an annual basis.
Although glass fibre
products have somewhat superior mechanical properties, their life cycle
performance is very questionable.
Manufacturing of these products not only
consume huge energy but their disposal at the end of their life cycle is also very
difficult since there is virtually no recycling option.
Annual industrial crops grown for fibre, have the potential to supply enough
renewable biomass for various bio-products including composites. The scope of
possible uses of natural fibres is enormous.
This is substantiated by the
declaration of United Nation for 2009 as International Year of Natural Fibres (IYNF).
All over the world, the bio-composite industry is developing at a significant pace to
meet growing consumer awareness and follow new environmental regulations. A
survey done by Canadian Agri-Food Research Council (CARC) in 2003 showed
that the European automotive industry has already taken the lead and uses
approximately 22,000 tons of natural plant fibre in low stress applications in cars.
In 2005, 19000 tones of natural fibres were used in Germany for automotive
composite. Lignocellulosic bio-fibre derived from various origins such as leaf, bast,
fruit, grass or cane; contribute to the strength of bio as well as synthetic polymer
composites in various applications. These fibres are renewable, non-abrasive to
process equipment, and can be incinerated at the end of their life cycle for energy
recovery as they possess a good deal of calorific value. They are also very safe
during handling, processing and use. Major natural fibres of vegetative origin used
as reinforcement are shown in Table- 1. Both thermoset and thermoplastic
matrices are used for development of natural fibre reinforced composite, the
comparative study of these two type of matrices are shown in Table- 2
2
Table: 1 Major natural fibres of vegetative origin used as reinforcement
Fibre
Type
Bagasse
Cane
Bamboo
Grass
Banana
Stem
Coconut husk
Fruit
Flax
Bast
Hemp
Bast
Jute
Bast
Kenaf
Bast
Sisal
Leaf
Wood
Stem
Advantages of natural fibre reinforced composites:

Reduction in density of products.

Acceptable specific strength, toughness and stiffness in comparison
with glass fibre reinforced composites.

Ease of shaping into complex shapes in a single manufacturing
process.

Lower energy consumption from fibre growing to finished composites

The manufacturing processes are relatively safe when compared with
glass based reinforced composites.

Possibility of recycling the cuttings and wastage produced during
manufacturing and moulding.

The production of natural fibres can be started with a low capital
investment and with a lower cost.

Bast fibres exhibit good thermal and acoustic insulation properties.
3
Table: 2 Summary of advantages and disadvantages of thermoset and
thermoplastics as matrix
Property
Thermoset
Thermoplastics
Formulations
Complex
Simple
Melt viscosity
Very low
High
Fibre impregnation
Easy
Difficult
Prepeg stability
Poor
Excellent
Processing cycle
Long
Short to long
Processing temperature Low to moderate high
High
/ pressure
Environmental durability
Good
Unknown
Solvent resistance
Excellent
Poor to good
Database
Very large
Small
The typical basic inherent characteristics of lignocellulosic fibre are shown in
Tables- 3 & 4.
Table: 3 Cell wall polymers responsible for the properties of lignocellulosics
in the order of importance
Biological Degradation
Moisture Sorption
Ultraviolet Degradation
Hemicellulose
Hemicellulose
Lignin
Accessible Cellulose
Accessible Cellulose
Hemicellulose
Non-Crystalline Cellulose
Non-Crystalline Cellulose
Accessible Cellulose
Lignin
Non-Crystalline Cellulose
Crystalline Cellulose
Crystalline Cellulose
Thermal Degradation
Strength
Hemicellulose
Crystalline Cellulose
Cellulose
Matrix (Non-Crystalline Cellulose + Hemicellulose + Lignin)
Lignin
Lignin
Ref: Chemical modification of agro-resources for property enhancement, Paper
and Composites from Agro-based resources. CRC Press, Boca Raton, 1996
4
Table: 4 Degradation reactions that occur when lignocellulosic resources
are exposed to nature.
Biological Degradation
Fire Degradation
Fungi, Bacteria, Insects, Termites
Lighting, Sun, Man
Enzymatic Reactions
Pyrolysis Reactions
Chemical Reactions
Water Degradation
Weather Degradation
Rain, Sea, Ice, Acid Rain
Ultraviolet Radiation, Water, Heat, Wind
Water Interactions
Chemical Reactions
Mechanical Degradation
Dust, Wind, Hail, Snow, Sand
Mechanical
Ref: Chemical modification of agro-resources for property enhancement, Paper
and Composites from Agro-based resources. CRC Press, Boca Raton, 1996
Disadvantages of natural fibre reinforced composites:

Lack of consistency of fibre quality, high level of variability in fibre
properties depending upon source and cultivars.

Preparation of fibre is labour intensive and time consuming.

Poor compatibility between fibres and matrix, which requires surface
treatment of fibres.

High moisture absorption, which brings about dimensional changes in
composite materials.

Low density of bast fibres can be disadvantageous during composites
processing application because fibre tends to migrate to the surface rather
then getting mixed with matrix.

Fluctuation in price depending upon the global demand and production.

Problem of storing raw material for extended time due to possibility of
degradation, biological attack of fungi and mildew, loss in colour, and foul
odour development.

Lower resistance to ultra violet radiation, which causes the structural
degradation of the composites.
5
Major R & D Work at IJIRA
Extensive R & D work has been carried out at IJIRA on jute reinforced composite
since early 80’s. The first work was carried out in collaboration with AERE,
Harwell, U.K. using high performance matrices i.e. epoxy, polyester etc. to
compare with mainly glass fibre reinforced composites.
From late 80’s the objective was concentrated to develop wood substitute by jute
composite targeting packaging and building materials. Low density polyethylene
films were used with jute non-woven and fabric for fabrication of jute composite.
These were tried for packaging of tea & horticultural produce. Some of the
mechanical properties are given in Tables-5 & 6.
Table: 5 Flexural Properties of jute composite from jute nonwoven and low
density polyethylene as matrix
Sl.
Samples
Flexural Strength
Flexural Modulus
Strain
(MPa)
(MPa)
%
31.84
1433
8.013
No.
1.
Jute non-woven* +
LDPE film
*Jute nonwoven- unidirectional & 400 gsm (nominal) *LDPE film- 50 gsm
Ref: “Studies on jute composite from jute nonwoven”, 16th Technological
conference, IJIRA, 11th – 12th Feb, 1993
Table: 6 Properties of jute composite from jute nonwoven and low density
polyethylene as matrix for packaging end- uses. (IIP- Kolkata)
Material
Average test value
Gram/m2
Puncture
Water
Bursting
Tensile
Mod. of
resistance
absorption
str.
str.
elasticity
oz-inch
(surface)
Kg/cm2
(MPa)
(MPa)
tear inch
24 hrs at 30
45.3
31.36
1756
C, gm/m2
Jute non-
1470
577.1
20.7
woven +
LDPE film
Ref: “Studies on jute composite from jute nonwoven”, 16th Technological
conference, IJIRA, 11th – 12th Feb, 1993
6
Lignocellulosic fibres are favourably bonded with phenolic resin to have better
water resistance rather than urea or melamine resin. Hence, water soluble phenol
formaldehyde resin was selected for the development of rigid jute board for good
serviceable mechanical properties. To achieve better wetability of jute with resin
and to improve strength properties, fibre pre-treatment is necessary. Simple pretreatment is done with low-condensed resins like melamine resin, phenolic resin
and CNSL modified phenol formaldehyde resin. Indicative physical properties of
jute composites from untreated & pre treated jute nonwoven with PF resin are
shown in Table-7.
Jute as other lignocellulosic fibres consists of –OH group which causes it
susceptible to moisture and directly impairs the properties of jute composite
specially dimensional stability. Due to this polar group, jute also is not efficiently
adhered to non polar matrices. To overcome this difficulties this fibre should be
modified chemically or hygrothermally. To improve the interface adhesion
between the non polar matrices and hydrophilic fibre, coupling agent or
compatibiliser should be used.
Some investigations were done by cyanoethylation and acetylation of jute fibre to
reduce the –OH content.
The both processes are effective for dimensional
stability. Cyanoethylation also improves the bonding between jute and non polar
matrix like unsaturated polyester resin.
Indicative properties of jute composites made from modified fibres with urea
formaldehyde resin & unsaturated polyester resin (USP) are given in Tables-8 & 9.
7
Table: 7 Physical properties of different jute composites
Sl.
Samples
No.
Tensile
Flexural
Flexural strength
strength
strength (Dry)
(After 2 hrs.
(MPa)
(MPa)
boiling in water)
(MPa)
1.
Untreated non-
42.10
68.24
22.17
49.99
73.97
27.50
47.70
72.32
26.13
62.21
90.03
58.27
woven* + PF resin
2.
MF pretreated nonwoven + PF resin
3.
PF pretreated nonwoven + PF resin
4.
CNSL – PF
pretreated nonwoven + PF resin
Ref: “Studies on jute composite from jute nonwoven”, 16th Technological
conference, IJIRA, 11th – 12th Feb, 1993
Table: 8 Effect of Cyanoethylation on Mechanical Properties of jute
composites
Sample
Control
Tensile
Strength
(MPa)
Flexural
Strength
(MPa)
Flexural
Mod
(GPa)
74.24
84.81
12.97
Water absorption
%
Thickness swelling %
2hr in
boiling
water
24hr in
cold
water
2hr in
boiling
water
24hr in cold
water
48.09
49.76
62.31
31.94
MJC-4
108.60
136.90
18.05
12.46
5.45
12.97
10.36
Ref: “Improvement of functional properties of jute based composite by acrylonitrile
pretreatment”, J. of Applied Polymer Science, vol. 78, 495-506 (2000)
8
Table: 9 Effect of Acetylation on Mechanical Properties of jute composites
Sl.
Samples
No.
Tensile
Flexural
Thickness
% Retention
% Retention of
strength
strength
swelling %
of tensile
flexural strength
(MPa)
(MPa)
strength after
after 5 cyclic
5 cyclic test
test (immersion
(immersion &
& oven dry)
1 hr
7 days
oven dry)
1.
CNa
62.92
39.13
29.00
40.80
30.35
24.12
2.
ANa
66.66
42.33
17.50
23.00
50.25
50.34
3.
CNH
56.25
37.12
23.5
37.55
29.35
26.25
4.
ANH
57.22
39.00
14.00
20.00
48.77
49.47
5.
CMF
49.58
40.21
17.00
20.70
55.70
55.12
6.
AMF
60.04
44.45
13.36
18.9
61.12
59.33
Jute sliver + 25% UF resin including additives
CNa- control jute sliver with NaCl and UF resin; ANa- acetylated jute sliver with NaCl and
UF resin;
CNH- control jute sliver with NH4Cl and UF resin;ANH- control jute sliver with NH4Cl and
UF resin;
CMF- control jute sliver with melamine and UF resin; AMF- control jute sliver with
melamine and UF resin;
Ref: “Effect of acetylation on dimensional stability, mechanical and dynamic
properties of jute board”, J. of Applied Polymer Science, vol.72, 935-944
(1999)
Hygrothermal pretreatment on jute fibre was done by spraying extra water on fibre
and was formed in square mat. The mat was placed in a closed mould and
pressed at 200 C for a few minutes to modify the fibre. These modified fibres
were moulded with PF resin as normal compression moulding process. Here the
dimensional properties have been improved but the other mechanical properties
have been reduced drastically due to thermal degradation of fibre and shown in
Table- 10.
9
Table: 10 Effect of Steam Pretreatment on properties of jute composites
Samples
Flex. Str.
kg/cm2
Flex. Mod.
Kg/cm2
Water absorption
%
24 h. 2 h boiling
Control
127.32
18578.84 166.57
137.13
SB4
39.28
12682.42
95.6
90.94
SRB4
85.87
13963.74
64.3
64.5
SB8
24.46
7412.00
88.93
87.26
SRB8
77.68
8825.40
56.75
60.18
Control- board from jute fibre + 7% PF;
Thickness swelling
%
24 h.
2 h boiling
77.65
97.27
18.69
24.45
16.07
24.24
11.98
21.67
11.52
21.09
SB4- board from 4 min. steam stabilized fibre.
SB8- board from 8 min. steam stabilized fibre.
SRB4- board from 4 min. steam stabilized fibre + 7% PF
SRB8- board from 8 min. steam stabilized fibre + 7% PF
Ref: “Effect of steam pretreatment of jute fibre on dimensional stability of jute
composite”, J. of Applied Polymer Science, vol.76, 1652-1661 (2000)
Process steps for fabrication of jute composite from thermoset resin:





Impregnation & drying- jute substrate (nonwoven / woven fabric) is
dipped in resin solution and squeezed to retain the required amount of
resin and then passed through dryer to reduce the moisture.
Cutting of substrate- The treated substrate is cut to size as per dimension
required.
Compression moulding- Books inside the platen are pressed to desired
specific pressure and temperature for pre defined time to get moulded
product. After completion of compression cycle, the platens are cooled to
optimum temperature & then the pressure is released to take out the
products.
Post curing- Compression moulded products are post cured in oven to get
fully cured and free from any precondensate polymer.
Cutting & sanding- The moulded product is trimmed and sanded.
For continuous moulded profile from jute reinforced composite, thermoplastic
matrix (PP) was used for melt blend with jute. In this process short jute fibre was
melt blended with polypropylene granules in presence of compatibilizer maleated
polypropylene. The properties are optimized on 60% jute fibre with 38%
polypropylene and 2% maleated polypropylene (Table- 11).
10
Table: 11 Effect of Compatibiliser on Mechanical Properties of Jute-PP
composites
Sample
J600
Tensile
Strength(MPa)
33.5
Tensile
Modulus(GPa)
Flexural
Flexural
Strength(MPa) Mod(GPa)
10.35
J602
68
10.50
J600- Jute fibre 60%, Polypropylene 40%
Water Absorption
%
2hr in
boiling
water
24hr in
cold
water
57.50
10.02
3.06
1.86
109
10
2.22
0.91
J602- Jute fibre 60%, Polypropylene 38%, Maleated polypropylene 2%
Ref: “Short jute fibre reinforced polypropylene composites: Effect of
compatibiliser”, J. of Applied Polymer Science, vol.69, 329-338 (1998)
Process steps for melt blend of jute PP:







Chopping- Jute fibre was stapled unto 100 mm
Granulating- Stapled jute fibres were further reduced in size unto 10 mm
(max) by passing through rotary granulating m/c
Mixing- Short jute fibres with matrix were mixed in Kinetic mixer m/c at
5500 rpm & 199 C to form dough
Pressing- Hot dough of mixture was flattened by pressing with hydraulic
press to release excess heat
Reduction of size- Flattened dough sheet was cut into pieces by running
through band saw
Granulating- Small pieces were further reduced in size by running through
granulator.
Injection molding- Granules of jute-pp were injection moulded to test
pieces.
Age old practice of fabrication of reinforced product is hand lay-up process. But
resin consumption is very high and productivity is very low due to long processing
time. New moulding technique, i.e. Resin Transfer Moulding, is used to replace
hand layup process for better productivity and quality.
Resin transfer moulding literally means the transfer of the matrix under pressure
to the closed mould containing the reinforcing substrate. This is the inverse
process of vacuum moulding. Mainly unsaturated polyester resin was used as
matrix. Work was done to evaluate the influence of jute as an additional substrate
with glass and some of the properties are shown in Table- 12
11
Table: 12 Flexural Properties of jute and jute-glass fibre composites
fabricated by resin transfer moulding
Sl.
no
Weight of fibre
Flex. Str.
Flex. Mod.
%
(MPa)
(GPa)
Jute
Glass
Total
1
33
-33
95.65
6.65
2
28
-28
82.55
5.85
3
18
15
33
121.51
6.88
4
-33
-153.77
7.12
Ref: “Jute composites by Resin Transfer Moulding- An improved alternatives for
hand lay up technique”, 20th Technological Conference, April 18, 1998
Pultrusion is a modern technique used for producing continuous fibre reinforced
profile in which the orientation of the fibre is kept constant during cure. This
process is suitable for thermosetting resins like polyester, epoxy & phenolic resin
systems. An infinite number of profiles can be produced using appropriate dies
and includes rods, tubes, flat & angle sections. Pultrusion technique has been
utilized for making door frame using jute as reinforcement and phenol
formaldehyde resin as matrix. This has been evaluated by Central Building
Research Institute, Roorkee & shown in the Table- 13.
Table: 13 Physico-mechanical properties of pultruded jute profile
Property
Value
A.
Physical properties
Bulk density (Kg/m3)
873
Moisture content (%)
4.41
Water absorption (%)
I. 2 hrs.
3.61
II. 24 hrs.
12.31
Surface water absorption (24 hrs., %)
1.52
Change in swelling (%)
I. Thickness
0.37
II. Length
0.013
III. width
0.041
Due to surface absorption (%)
Negligible
B.
Mechanical properties
Flexural yield strength (MPa)
62.60
Modulus of elasticity (GPa)
5.31
Tensile strength (MPa)
33.0
Elongation (%)
0.86
Tensile modulus (GPa)
7.98
Internal bond strength (MPa)
0.66
Screw withdrawal strength (N), Face
1800
Ref: “Suitability assessment of JRP Pultruded profile as door frame materials in
building”, Report No. F(C) 0176, Feb. 1998, Organic Building Materials
Division, CBRI, Roorkee.
12
Application areas of jute reinforced polymer composites
with technical advantages
Application areas
Advantages
Automobile industries
 door panels
 seat backs
 headliners,
 dash boards
 trunk liners




Building Component
 Door
 Window
 Wall partition
 Ceiling
 Floor


Transport Sector (railway coach &
vehicle)
 Flooring
 Ceiling
 Seat & Backrest


Furniture
 Table
 Chair
 Kitchen cabinet etc.






Lighter in weight
Lesser raw material
Cost economic
Serviceable mechanical
properties
Use of renewable resource
Better physical properties
Fire, termite & better moisture
resistance properties
Available at semi finished /
finished state i.e. reduced
labour & finishing cost
Better physical properties
Fire, termite & better moisture
resistance properties
Available at semi finished /
finished state i.e. reduced
labour & finishing cost
Better physical properties
Fire, termite & better moisture
resistance properties
Available at semi finished /
finished state i.e. reduced
labour & finishing cost
Future R & D plan
Broadly defined bio-composite are composite materials made from natural fibre
and petroleum derived non biodegradable polymers like polyester, phenolic, PP
etc. These polymer matrices are becoming costlier because of the fluctuating
price of petrochemicals. These resins could be made cheaper by modification
with cheaper bio-resources.
Bio-composite derived from plant fibre & crop / bio-derived plastic are likely
more eco-friendly and such bio-composites are termed as green composite.
Future attempt would therefore be to develop cheaper biodegradable matrix
utilizing modification of bio-resources.
13