Hemp fiber and its composites – a review

Abstract

The use of hemp fibers as reinforcement in composite materials has increased in recent years as a response to the increasing demand for developing biodegradable, sustainable, and recyclable materials. Hemp fibers are found in the stem of the plant which makes them strong and stiff, a primary requirement for the reinforcement of composite materials. Themechanical properties of hemp fibers are comparable to those of glass fibers. However their biggest disadvantage is the variability in their properties. Composites made of hemp fibers with thermoplastic, thermoset, and biodegradable matrices have exhibited good mechanical properties. A number of hemp fiber surface treatments, used to improve the fiber/matrix interfacial bonding, have resulted in considerable improvements in the composites’ mechanical properties.

Hemp Made Bio-Composites

“…Thermoplastics start to melt at a specific temperature (34) and owing to the thermal limits of the natural fibers only some low-melting thermoplastics may be used. Thermoplastics have significant viscosity and therefore their good wetting with natural fibers is difficult to achieve (11). In order to achieve the reduction of viscosity it is necessary to increase the temperature of thermoplastics.…”

Characterisation of the Anisotropic Thermoelastic Properties of Natural Fibres for Composite Reinforcement

“…However, the increasing pressure on natural resources and the large amounts of energy required in glass fibre production has led to an upsurge in the research of fibres derived from natural sustainable plant sources as potential reinforcements for high performance composite materials [2][3][4][5][6][7][8][9][10][11]. Many academic researchers argue that plant-based natural fibres (NF) can successfully compete with glass fibres in today's market because of their attractive properties, which may include low cost, low density, good specific strength properties, renewable, carbon dioxide neutrality emissions, and sustainability [3][4][5][6][7][8]. Nevertheless, a certain level of reinforcement performance is still required from such fibres in order to succeed in engineering composite applications.…”

“…Nevertheless, a certain level of reinforcement performance is still required from such fibres in order to succeed in engineering composite applications. In this context, many researchers refer to the respectable level of axial modulus exhibited by some natural fibres, which can be made to appear more attractive by comparing modulus/density ratios [2][3][4][5][6][7][8][9][10][11]. An interesting point about such claims is that both low density and specific performance are claimed to be advantages for NF.…”

“…These have been developed by the composites community, based on the use of well-defined, uniformly cylindrical, often isotropic, man-made fibres with very low levels of variability. The assumption that these models and methods can be applied to complex, anisotropic, non-cylindrical NF, which have a high level of batch-to-batch, inter-fibre and intra-fibre variability [2,6,[12][13][14][15][16][17], is open to question. In order to effectively predict realistic values for the properties of natural fibre reinforced composites, it is essential to fully appreciate the relevant properties of the constituent materials.…”

Development and Study of Tribological Properties of Biocomposite for Brake Pad Application

“…Hemp fibers contain more cellulose content which provides it more thermal stability and it contains a reasonable lignin content which is removable by NAOH treatment for increasing the compatibility with the matrix [2]. Epoxy is chosen as resin for the composite since it is found to be compatible with hemp fiber [5]. Cashew friction dust is derived from cashew nut shell which is ultimately a waste after cashew is being removed from it and it is also a bio material [1].…”