Seyed Hamidreza Ghaffar

The Influence of Additives on the Interfacial Bonding Mechanisms Between Natural Fibre and Biopolymer Composites

There has not been extensive research into the subjects of the interfacial bonding quality and the interaction mechanisms of biopolymers and natural fibres. Attempts have been made to incorporate natural fibres/fillers (biofibres) into the manufacture of composites in order to increase the functionality and performance of biopolymers synthesised from natural sources/microbial systems. However, the interfacial bonding quality and other substantial technical challenges still need to be addressed if their industrial use is to be realized. The interfacial bonding quality ultimately dictates the mechanical and physical performance of bio-composites. This review paper attempts to collate the state-of-the-art regarding coupling agents/additives and their roles in interaction mechanisms with biofibres and biopolymers. Two potential pathways for narrowing the performance gap between biopolymer-based bio-composites and their petroleum-based counterparts are: i) improving the interfacial bonding quality by the synthesis of a specific coupling agent, and ii) improving the processability of bio-composites by blending two or more biopolymers.

Detailed Analysis of Wheat Straw Node and Internode for their Prospective Efficient Utilisation

In order to efficiently utilize wheat straw, the systematic examination of their cell wall components, chemical structures, morphology, and relation to the physicochemical and mechanical properties is necessary. Detailing of node and internode signifies their different features and characteristics which can ultimately lead to their separated processing for enhanced efficiency and higher value-added biorefinery. In this study, distinct variations were found among characteristics of node and internode, inner and outer surface. It was revealed that the node has more extractives, Klason lignin, and ash content than the internode; higher contents of extractives and ash in the node are related to the thicker epidermis tissue. Hot water followed by mild steam pretreatment was used to examine the effects on the characteristics of wheat straw. The results showed: (1) reduced level of waxes and Si (weight %) from the outer surface and (2) significantly lower (P < 0.05) extractives content in both internode and node.

Impact Properties of Hemp Fibre Reinforced Cementitious Composites

The construction industry has seen an incredibly fast increase in utilizing natural fibres for making low-cost building materials to achieve sustainable construction. One of such applications is natural fibre-reinforced cementitious materials for either structural or non-structural purpose. Impact properties are engineering properties received increasing attentions from engineering community for structural materials. This research therefore studies impact resistance of hemp fibre reinforced cementitious composites at early ages. Hemp fibre with various lengths, 10 mm and 20 mm, are utilized to reinforce cementitious materials. Hemp fibre reinforced cementitious composite slabs were tested under repeating dropping mass till failure at the age of 7, 14 and 28 days. Cracking behaviour, impact resistance, absorbed impact energy and survived impact blows upon failure are qualitatively/quantitatively analysed. It has been found that 20 mm-long hemp fibre reinforcement leads to higher impact resistance, more absorbed impact energy and survived more impact blows upon failure. Cementitious composite slabs reinforced by 20 mm-long hemp fibres exhibit higher impact crack resistance ratio than those reinforced by 10 mm-long fibres. Longer fibres are more effective in inhibiting the growth of micro-cracks and blunting the propagation of micro-cracks before they join up to form macro cracks leading to ultimate failure.