Mechanical properties plant fibres

Pineapple leaf fibre (PALF), which is rich in cellulose, relatively inexpensive and abundantly available has the potential for polymer-reinforced composite. PALF at present is a waste product of pineapple cultivation. Hence, without any additional cost input, pineapple fibres can be obtained for industrial purposes. Among various natural fibres, PALFs exhibit excellent mechanical properties. These fibres are multicellular and lignocellulosic. They are extracted from the leaves of the plant Ananus cosomus belonging to the Bromeliaceae family by retting. The main chemical constituents of pineapple fibres are cellulose (70-82%), lignin (5-12%) and ash (1.1%). The superior mechanical properties of PALFs are associated with their high cellulose content. 

Natural fibres can be derived either from plants (such as flax or hemp), produced by animals (such as silk or spider silk) or from minerals (such as asbestos). Table 6.1 shows the comparison of selected physical properties between natural fibres and synthetic fibres. Although the mechanical properties of natural fibres are very much lower than those of conventional synthetic fibres, such as glass or carbon fibres. 

Nakagaito AN, Yano H (2004) The effect of morphological changes from pulp fibre towards nanoscale fibrillated cellulose on the mechanical properties of high-strength plant fibre based composites. Appl Phys A 78 547-552... 

Kenaf is an herbaceous annual plant that is grown commercially in the USA in a variety of weather conditions, and it has been previously used for rope and canvas. Kenaf has been deemed extremely environmentally friendly for two main reasons (a) kenaf accumulates carbon dioxide at a significantly high rate and (b) kenaf absorbs nitrogen and phosphorous from the soil [17]. In addition, kenaf, like most other natural fibres, demonstrates low density, high specific mechanical properties, is easily recycled and maintains a competitive price. 

Wood is made of plant cells elongated in the axial direction of the tree or branch. The mechanical properties of wood are determined by the cell walls which are a composite of a natural polymer matrix with cellulose fibres [9, 144]. Cellulose is a polysaccharide, a chain molecule with sugar molecules as... 

Hazarika A, Maji TK (2014c) Strain sensing behavior and dynamic mechanical properties of carbon nanotubes/nanoclay reinforced wood polymCT nanocomposite. Chem Eng J 247 33-41 Hazarika A, Maji TK (2014d) Thermal decomposition kinetics, flammability, and mechanical property smdy of wood polymtar nanocomposite. J Therm Anal Calorim 115 1679-1691 Hazarika A, Mandal M, Maji TK (2014) Dynamic mechanical analysis, biodegradability and thermal stability of wood polymer nanocomposites. Compos Part B 60 568-576 Hetzer M, Kee D (2008) Wootl/polymer/nanoclay composites, environmentally friendly sustainable technology a review. Chem Eng Res Des 86 1083-1093 Hill CAS, Abdirl KHPS, Hale MD (1998) A study of the potential of acetylation to improve the properties of plant fibres, frrd Crops Prod 8 53-63 Hoffmann MR, Martin ST, Choi WY, Bahnemann W (1995) Environmental application of semiconductm photocatalysis. Chem Rev 95 69-96 Huda MS, Drzal LT, Misra M, Mohanty AK (2(K)6) Wood-fiber-reinforced poly(lactic acid) composites evaluation of the physicomechanical and morphological properties. J AppI Polym Sci 102 4856-4869... 

Wood or plant fibres are of interest in polymer reinforcement for a number of reasons, espeeially their low cost, low weight and non-abrasiveness to proeessing equipment. In addition, natural fibres are C02-neutral when burned, have attractive aeoustic and thermal insulation properties and have good specific mechanical properties. The research literature contains many examples of studies in whieh the reinforcement of non-degradable thermoplastics like polypropylene (PP), polyethylene (PE), polyvinyl ehloride (PVC) and polyesters with wood or plant fibres has been investigated (Bledzki and Gassan, 1999 Kandaehar, 2002). Reinforcement of thermosets such as epoxies and polyurethanes with natural fibres has also been explored. A summary of the mechanieal properties of selected plant fibres derived from various literature sourees is shown in Table 8.1 (Lilholt and Lawther, 2000 Kandaehar, 2002 Bledzki and Gassan, 1999 Wambua et al, 2003). 

The impact properties of injection-moulded Mater-Bi (R) were increased by 30% when the matrix was reinforced with miscanthus fibres (Johnson et al, 2003). Key factors in determining composite properties were the temperature of the extruder barrel and the extruder screw speed. A summary of plant fibre-thermoplastic starch composite mechanical properties is presented in Table 8.4. 

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