Natural fiber reinforced composites is an emerging area in polymer science. These natural fibers are low cost fibers with low density and high specific properties. These are biodegradable and non-abrasive. The natural fiber composites offer specific properties comparable to those of conventional fiber composites. However, in development of these composites, the incompatibility of the fibers and poor resistance to moisture often reduce the potential of natural fibers and these draw backs become critical issue. This review presents the reported work on natural fiber reinforced composites with special reference to the type of fibers, matrix polymers, treatment of fibers and fiber-matrix interface. © 1999 John Wiley & Sons, Inc. Adv in Polymer Techn 18: 351–363, 1999

Natural fiber polymer composites: A review

Biofibres and Biocomposites

Sisal fibre and its composites: a review of recent developments

Dynamic mechanical analysis of banana fiber reinforced polyester composites

Summary: The use of lignocellulosic fibers, pineapple leaf fiber (PALF) and sisal as reinforcements in thermoplastic and thermosetting resins for developing low cost and lightweight composites is an emerging field of research in polymer science and technology. Although, these biofibers have several advantages, such as low densities, low cost, nonabrasive nature, high filling level possible, low energy consumption, high specific properties, biodegradability, etc., over synthetic fibers, the absorption of moisture by untreated biofibers, poor wettability, and insufficient adhesion between the polymer matrix and fiber deteriorate the mechanical properties of composites made up of these biofibers. Therefore, the modification of these fibers is a key area of research at present to obtain optimum fiber-matrix properties. This review article is concerned with the structure, composition and properties of PALF and sisal, the chemical modifications of these fibers and PALF/sisal-reinforced thermosets, thermoplastics, rubber, cement, hybrids and biocomposites.

Scanning electron micrograph of tensile fractured surface of alkali treated sisal fiber (magnification ×500).

A Review on Pineapple Leaf Fibers, Sisal Fibers and Their Biocomposites

The effect of a two-component dry bonding system consisting of resorcinol and hexamethylene tetramine on the mechanical and viscoelastic properties of short sisal fiber reinforced natural rubber composites has been studied. The studies were conducted with chemically treated and untreated short sisal fibers. Treated fibers impart better mechanical properties to the composites. By mixing with short fibers, the dynamic storage modulus (E') of natural rubber composites was improved. The effects of fiber-matrix adhesion on the mechanical and viscoelastic properties of the composites were investigated. The storage moduli and mechanical loss increased continuously with an increase in fiber loading but decreased with an increase of temperature. The influence of the fiber orientation on the mechanical and viscoelastic properties is discussed.

Mechanical and viscoelastic properties of short fiber reinforced natural rubber composites: effects of interfacial adhesion, fiber loading, and orientation

Studies on the effect of blend ratio and crosslinking system on thermal, X-ray and dynamic mechanical properties of blends of natural rubber and ethylene-vinyl acetate copolymer

Studies on the effect of blend ratio and cure system on the degradation of natural rubber—ethylene-vinyl acetate rubber blends

The melt rheology of blends of natural rubber (NR) and ethylene–vinyl acetate copolymer (EVA) has been studied with reference to the effects of blend ratio, cross-linking systems, shear stress, and temperature. When EVA formed the dispersed phase, the viscosity of the blends was found to be a nonadditive function of the viscosities of the component polymers at lower shear region, i.e., a positive deviation was observed. This behavior has been explained based on structural buildup of dispersed EVA domains in the continuous NR matrix. The effect of the addition of silica filler on the flow characteristics of the blends has been investigated. The melt elasticity parameters such as die swell, principal normal stress difference, recoverable shear strain, and elastic shear modulus of NR–EVA blends were also evaluated. © 1993 John Wiley & Sons, Inc.

Melt rheology and elasticity of natural rubber—ethylene–vinyl acetate copolymer blends

The viscoelastic properties such as storage modulus (E′), loss modulus (E”) and damping (tan δ) of unfilled and silica-filled blends of natural rubber (NR) and ethylene-vinyl acetate copolymer (EVA) have been evaluated. The blends were crosslinked by a mixed system consisting of accelerated sulfur and peroxide. The tan δ values of unfilled blends showed two transitions corresponding to EVA and NR phases. This indicated that the blends are immiscible. The damping curves of EVA and EVA-rich blends possess three distinct regions: a rubbery plateau, a melt transition, and a viscous plateau. It is seen that the addition of silica decreased the tan δ values of the samples substantially except that of NR, where a slight increase in tan δ values can be observed at high temperatures. The sharp decrease in tan δ in filled EVA and EVA-rich blends is associated with the decrease in crystallinity of the EVA phase due to the presence of filler. Addition of silica filler increased the storage and loss modulus o...

Alex T. Koshy

Papers

Mechanical and viscoelastic properties of short fiber reinforced natural rubber composites: effects of interfacial adhesion, fiber loading, and orientation

Studies on the effect of blend ratio and crosslinking system on thermal, X-ray and dynamic mechanical properties of blends of natural rubber and ethylene-vinyl acetate copolymer

Studies on the effect of blend ratio and cure system on the degradation of natural rubber—ethylene-vinyl acetate rubber blends

Melt rheology and elasticity of natural rubber—ethylene–vinyl acetate copolymer blends

Viscoelastic Properties of Silica-Filled Natural Rubber and Ethylene-Vinyl Acetate Copolymer Blend