ARB Presentation for the engineering applications

edfffffffffffff gfffffffffffffff

1. NATURAL FIBRES

2. ADVANTAGES OF USING NATURAL FIBRE Obtained from Renewable Sources Requires little energy during production Recyclable Environmentally friendly during stages of production, processing and waste disposal Light Weight Producible with low investment at low cost Acceptable Specific Strength Properties Better Wear Protection Good thermal and acoustic insulating properties

3. DISADVANTAGES OF USING NATURAL FIBRE Moisture absorption , which causes swelling of the fibres. These are UV-sensitive . Lower durability . Low impact strength . Fibre degradation during processing.

4. S ome Natural Fibres and their Applications in Composites 1. Flax 2. Hemp 3. Jute 4. Coir 5. Asbestos

5. FLAX 1 Flax is an annual crop for multipurpose use: fibre and oil production, non-textile applications like in composites. The relevant part for fibre production is the stem . The stem has a length which goes from 600 to 1000 mm. For composite use, the length of 10 to 20 mm is sufficient. For the industrial use, the non-retted stems are dominantly mechanically decorticated.

6. Properties: Flax fibre is an ecologically safe alternative to reinforcing fibres in plastic composites. Flax fibres are less dense than glass fibres, are renewable and combustible , and they are less expensive. Strength and toughness of flax fibre are comparable to those of glass fibres. Applications: In 1941, flax and hemp fibres were used in resin matrix composites for the bodywork of a Henry Ford car which was claimed to have an “impact strength 10 times greater than steel”. These are typically combined with polypropylene, polyester, or polyurethane to produce components like door and trunk liners, parcel shelves, seat backs, interior sunroof shields, and headrests . Recently, flax has also been employed lo reinforce thermosetting resin (i.e., epoxy) in order to realize structural components for automotive and marine ships with high performances.

7. Biodegradability: At high temperatures, natural fibres start degrading whereas constituents of fibre may start decomposing at earlier temperatures. The thermal stability can be improved if the concentration levels or the structural constituents are completely removed by chemical treatments. Natural fibres have a short lifetime with minimum environmental damage upon degradation whereas synthetic ones affect environment due to pollution caused by degradation. Energy Absorptions: High strength, energy absorption, and stiffness are obtained by composite materials which are widely used in automotive and motorsport sectors of industry mainly due to the property of mass reduction. Enhanced energy absorption is evident from the increased volume fraction that is only possible in the presence of low speed. On the other hand, at high speeds, similar performance is shown by flax, jute, and hemp.

8. Water Absorbent Properties: The main weakness of the application of natural fibres is their susceptibility to moisture. The natural fibres are rich of components which are hydrophilic sources and strong polar while the polymers show hydrophobicity. These can cause warping, buckling, bigger possibility of their microbial inhabitation, freeze, and unfreeze caused destruction of mechanical characteristics of composite materials. The effect of coupling agent such as maleic anhydride polyethylene and chemical treatments such as bleaching, acetylation, and alkali treatment reduces moisture absorption of natura fibre-based composites. Thermal Properties: Enzymatic treatment for many natural fibres such as flax and hemp often can lead to improvement in surface and thermal properties.

9. Industrial Applications of Natural Fibre based Composite Materials

10. AUTOMOTIVE INDUSTRY The automotive industry has developed various new components based on natural fibre composites. Only non-structural or semi-structural components are realized by mainly using polyester resin or thermoplastic polymers and lignocellulosic fibres (i.e., flax, hemp, sisal and jute). Bast fibre composites are predominantly used in automotive interior panels , such as doors, pillar, trim, trunk liners and package or real parcel trays. Flax or sisal material can be molded in complicated 3D shapes, thus making it more suitable for door trim panels than the previously used materials.