Biocomposites reinforced with natural fibers: 2000–2010

Mechanical properties of natural fibre reinforced polyester composites: Jowar, sisal and bamboo

The structure of the isolated milled “wood” lignin from coconut coir has been characterized using different analytical methods, including Py-GC/MS, 2D NMR, DFRC, and thioacidolysis. The analyses demonstrated that it is a p-hydroxyphenyl-guaiacyl-syringyl (H-G-S) lignin, with a predominance of G units (S/G ratio 0.23) and considerable amounts of associated p-hydroxybenzoates. Two-dimensional NMR indicated that the main substructures present in this lignin include β–O–4′ alkyl aryl ethers followed by phenylcoumarans and resinols. Two-dimensional NMR spectra also indicated that coir lignin is partially acylated at the γ-carbon of the side chain with p-hydroxybenzoates and acetates. DFRC analysis showed that acetates preferentially acylate the γ–OH in S rather than in G units. Despite coir lignin’s being highly enriched in G-units, thioacidolysis indicated that β–β′ resinol structures are mostly derived from sinapyl alcohol. Finally, we find evidence that the flavone tricin is incorporated into the coconut co...

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Structural Characterization of Lignin Isolated from Coconut (Cocos nucifera) Coir Fibers

Chemical composition modification and surface modification of coir fibers are made in view of their use as reinforcement in coir-based green composites. Composites were prepared using coir fiber treated with varying pretreatment condition. The changes in the proportion of chemical composition and morphological properties of coir fibers with different coir pretreatment condition were discussed. It is observed that the mechanical properties of coir-based green composites; modulus of rupture and internal bond, increase as a result of chemical composition modification and surface modification. Scanning electron microscopy (SEM) investigations show that surface modifications improve the fiber/matrix adhesion.

Materials and mechanical properties of pretreated coir-based green composites

This study examined the mechanical and thermophysical behavior of green composites. In the preparation procedure of the composite, a plasma treatment was applied to the surface of the coconut fibers to improve the interfacial adhesion between the fibers and matrix. The coconut fiber-reinforced PLA composites were prepared using the commingled yarn method. The mechanical properties of the composites, such as tensile strength, Young’s modulus, and elongation at break were examined, and the shrinkage and flame retardant properties of the specimens were measured. From these experiments, the effect of the plasma treatment on the mechanical and thermophysical behavior of the coconut fibers/PLA composites was identified. In addition, morphological analysis was performed using scanning electron microscopy.

Wei Wang

Papers

Characterisation and utilization of natural coconut fibres composites