Jute composite and its applications - International Jute …jute.org/Documents_Seminar_Workshop_Meeting/Jute... · Web viewBoth thermoset and thermoplastic matrices are used for development

Jute composite and its applications

S. Das

Indian Jute Industries’ Research Association17 Taratola Road, Kolkata-700088, India

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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

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Table: 1 Major natural fibres of vegetative origin used as reinforcement

Fibre TypeBagasse 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.

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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 / pressure

Low to moderate high High

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 DegradationHemicellulose

Accessible Cellulose

Non-Crystalline Cellulose

Moisture SorptionHemicellulose



Lignin

Crystalline Cellulose

Ultraviolet DegradationLignin

Hemicellulose



Crystalline Cellulose

Thermal DegradationHemicellulose

Cellulose

Lignin

StrengthCrystalline Cellulose

Matrix (Non-Crystalline Cellulose + Hemicellulose + Lignin)

Lignin

Ref: Chemical modification of agro-resources for property enhancement, Paper

and Composites from Agro-based resources. CRC Press, Boca Raton, 1996

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Table: 4 Degradation reactions that occur when lignocellulosic resources are exposed to nature.

Biological Degradation

Fungi, Bacteria, Insects, Termites

Enzymatic Reactions

Chemical Reactions

Fire Degradation

Lighting, Sun, Man

Pyrolysis Reactions

Water Degradation

Rain, Sea, Ice, Acid Rain

Water Interactions

Weather Degradation

Ultraviolet Radiation, Water, Heat, Wind

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.

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Major R & D Work at IJIRAExtensive 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.

No.

Samples Flexural Strength

(MPa)

Flexural Modulus

(MPa)

Strain

%

1. Jute non-woven* +

LDPE film

31.84 1433 8.013

*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

resistance

oz-inch

tear inch

Water

absorption

(surface)

24 hrs at 30

C, gm/m2

Bursting

str.

Kg/cm2

Tensile

str.

(MPa)

Mod. of

elasticity

(MPa)

Jute non-

woven +

LDPE film

1470 577.1 20.7 45.3 31.36 1756



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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 pre-

treatment 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.

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Table: 7 Physical properties of different jute composites

Sl.

No.

Samples Tensile

strength

(MPa)

Flexural

strength (Dry)

(MPa)

Flexural strength

(After 2 hrs.

boiling in water)

(MPa)

1. Untreated non-

woven* + PF resin

42.10 68.24 22.17

2. MF pretreated non-

woven + PF resin

49.99 73.97 27.50

3. PF pretreated non-

woven + PF resin

47.70 72.32 26.13

4. CNSL – PF

pretreated non-

woven + PF resin

62.21 90.03 58.27



Table: 8 Effect of Cyanoethylation on Mechanical Properties of jute composites

Sample Tensile Strength (MPa)

Flexural Strength (MPa)

Flexural Mod

(GPa)

Water absorption%

Thickness swelling %

2hr in boiling water

24hr in cold

water


24hr in cold water

Control 74.24 84.81 12.97 48.09 49.76 62.31 31.94

MJC-4 108.60 136.90 18.05 12.46 5.45 12.97 10.36Ref: “Improvement of functional properties of jute based composite by acrylonitrile pretreatment”, J. of Applied Polymer Science, vol. 78, 495-506 (2000)

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Table: 9 Effect of Acetylation on Mechanical Properties of jute composites

Sl.

No.

Samples Tensile

strength

(MPa)

Flexural

strength

(MPa)

Thickness

swelling %

% Retention

of tensile

strength after

5 cyclic test

(immersion &

oven dry)

% Retention of

flexural strength

after 5 cyclic

test (immersion

& oven dry)

1 hr 7 days

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.

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Table: 10 Effect of Steam Pretreatment on properties of jute composites

Samples Flex. Str. kg/cm2

Flex. Mod. Kg/cm2

Water absorption%

Thickness swelling%

24 h. 2 h boiling 24 h. 2 h boilingControl 127.32 18578.84 166.57 137.13 77.65 97.27

SB4 39.28 12682.42 95.6 90.94 18.69 24.45SRB4 85.87 13963.74 64.3 64.5 16.07 24.24SB8 24.46 7412.00 88.93 87.26 11.98 21.67

SRB8 77.68 8825.40 56.75 60.18 11.52 21.09Control- board from jute fibre + 7% PF;

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).

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Table: 11 Effect of Compatibiliser on Mechanical Properties of Jute-PP composites

Sample Tensile Strength(MPa)

Tensile Modulus(GPa)

Flexural Strength(MPa)

Flexural Mod(GPa)

Water Absorption%


24hr in cold

water

J600 33.5 10.35 57.50 10.02 3.06 1.86

J602 68 10.50 109 10 2.22 0.91J600- Jute fibre 60%, Polypropylene 40%

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

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Table: 12 Flexural Properties of jute and jute-glass fibre composites fabricated by resin transfer moulding

Sl. no

Weight of fibre%

Flex. Str.(MPa)

Flex. Mod. (GPa)

Jute Glass Total1 33 -- 33 95.65 6.652 28 -- 28 82.55 5.853 18 15 33 121.51 6.884 -- 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 ValueA. Physical properties

Bulk density (Kg/m3) 873Moisture content (%) 4.41Water absorption (%)

I. 2 hrs.II. 24 hrs.

3.6112.31

Surface water absorption (24 hrs., %) 1.52Change in swelling (%)

I. ThicknessII. LengthIII. width

0.370.0130.041

Due to surface absorption (%) NegligibleB. Mechanical properties

Flexural yield strength (MPa) 62.60Modulus of elasticity (GPa) 5.31Tensile strength (MPa) 33.0Elongation (%) 0.86Tensile modulus (GPa) 7.98Internal bond strength (MPa) 0.66Screw 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.

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Application areas of jute reinforced polymer compositeswith technical advantages

Application areas Advantages

Automobile industries door panels seat backs headliners, dash boards trunk liners

Lighter in weight Lesser raw material Cost economic Serviceable mechanical

properties Use of renewable resource

Building Component Door Window Wall partition Ceiling Floor

Better physical properties Fire, termite & better moisture

resistance properties Available at semi finished /

finished state i.e. reduced labour & finishing cost

Transport Sector (railway coach & vehicle)

Flooring Ceiling Seat & Backrest




Furniture Table Chair Kitchen cabinet etc.




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.

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