Home | About Jute | Jute Prices | Organisation | Directory | Technology | Statistics | Diversification | Jute Policy | Jute News | FAQ

 Jute Reinforced Composite Technology

Natural Fibres
Jute, sisal, banana and coir, the major source of natural fibres, are grown in many parts of the world. Some of them have aspect ratios (ratio of length to diameter) > 1000 and can be woven easily. These fibres are extensively used for cordage, sacks, fishnets, matting and rope, and as filling for mattresses and cushions (e.g. rubberised coir). Cellulosic fibres are obtained from different parts of plants, e.g. jute and ramie are obtained from the stem; sisal, banana and pineapple from the leaf; cotton from the seed; coir from the fruit, and so on.

Recent reports indicate that plant-based natural fibres can very well be used as reinforcement in polymer composites, replacing to some extent more expensive and non-renewable synthetic fibres such as glass. The maximum tensile, impact and flexural strengths for natural fibre reinforced plastic (NFRP) composites reported so far are 104.0 MN/m2 (jute-epoxy), 22.0 kJ/m2 (jute-polyester) and 64.0 MN/m2 (banana-polyester), respectively.

The properties of some of the natural fibres are compared in Table 1.0.
Table 1.0: 
Properties of Select Natural & Glass Fibres
Property: Jute Banana Sisal Pineapple CoirGlass
Width or Diameter (mm) -80-25050- 20020- 80100-4507-8
Density(gms./cc)1.31.351.451.441.152.5
Volume Resistivity at 100 volts (W cm x 105)-6.5-70.4-0.50.7-0.89-149-10
Micro-Fibrillar Angle (degree) 8.11110-2214-1830-49-

Cellulose/Lignin Content (%)61 /1265 /567 /1281 /1243 /45-
Elastic Modulus (GN/m2)-8-209-1634-824-685.5 Tenacity (MN/m2)440-533529-754568-640413-1627131-1754585 Elongation (%)1-1.21.0-3.53-70.8-1.615-405.7 Moisture Absorption after 24 h (%)6-9---120.5 Aspect Ratio (L/D) (mm)152-365----100-140.
There are many examples of the use of cellulosic fibres in their native condition like sisal, coir jute, banana, palm, flax, cotton, and paper for reinforcement of different thermoplastic and thermosetting materials like phenol-formaldehyde, unsaturated polyester, epoxy, polyethylene, cement, natural rubber, etc.

Different geometries of these fibres, both singly and in combination with glass, have been employed for fabrication of uni-axial, bi-axial and randomly oriented composites. Amongst these various ligno-cellulosic fibres, jute contains a fairly high proportion of stiff natural cellulose [1,2].  Rated fibres of jute have three principal chemical constituents, namely, a -cellulose, hemicellulose and lignin. In addition, they contain minor constituents such as fats and waxes, inorganic (mineral) matter, nitrogenous matter and traces of pigments like b - carotene and xanthophyll.  As in synthetic fibre composites, the mechanical properties of the final product depend on the individual properties of the matrix, fibre and the nature of the interface between the two. Where the fibre is an agricultural one, it is possible to tailor the end properties of the composite by selection of fibers with a given chemical or morphological composition.

Several studies of fiber composition and morphology have found that cellulose content and microfibril angle tend to control the mechanical properties of cellulosic fibers. Pavithran et al [3] found that higher cellulose content and lower microfibril angle resulted in higher work of fracture in impact testing.

Jute and Glass Fibres
Although the tensile strength and Young’s modulus of jute are lower than those of glass fibres, the specific modulus of jute fibre is superior to that of glass and when compared on modulus per cost basis, jute is far superior. The specific strength per unit cost of jute, too, approaches that of glass. Therefore, where high strength is not a priority, jute may be used to fully or partially replace glass fibre.

The need for using jute fibres in place of the traditional glass fibre partly or fully as reinforcing agents in composites stems from its lower specific gravity (1.29) and higher specific modulus (40 Gpa) of jute compared with those of glass (2.5 & 30 Gpa respectively) [4]. Apart from much lower cost and renewable nature of jute, much lower energy requirement for the production of jute (only 2% of that for glass) makes it attractive as a reinforcing fibre in composites. The comparison of mechanical properties for jute & glass fibres is given in Table 2.0.

Table 2.0 : Mechanical Properties of Glass and Jute Fibres
Property E-glassJute
Specific Gravity 2.51.3
Tensile Strength (MN/m2 ) 3400442
Young’s Modulus (MN/m2 ) 7255.5
Specific Strength (MN/m2 ) 1360340
Specific Modulus (GN/m2 ) 28.842.7

The jute composites may be used in everyday applications such as lampshades, suitcases, paperweights, helmets, shower and bath units. They are also used for covers of electrical appliances, pipes, post-boxes, roof tiles, grain storage silos, panels for partition & false ceilings, bio-gas containers, and in the construction of low cost, mobile or pre-fabricated buildings which can be used in times of natural calamities.