CLOSED MOULD PROCESSING AND CHARACTERISATION OF SHORT FIBRE REINFORCED COMPOSITES

Abstract

Composite materials are a combination of matrix and fiber where role of fiber is to provide rigidity and of matrix is to bind fibers together. Composites have high specific strength owing to their low weight. Based on the type of fiber used, composites can be classified into synthetic fiber composites having fibers such as glass, aramid, carbon fiber etc. and natural fiber composites having fibers such as jute, banana, kenaf, hemp etc. Advantages of natural fibers as compared to synthetic fibers include recyclability, low energy consumption, nonabrasive nature, wide availability etc. India is one of the largest producers of banana and after cultivation of fruit huge amount of biomass becomes waste. This waste can be utilized for manufacturing banana fibre composites which will be beneficial for environment as well as rural economy. As compared to other natural fibres, banana fibers have high tensile strength and low moisture absorption. Use of polypropylene as matrix in increasing due to its low cost, easy availability, high mechanical properties and easy moldability. Natural fibres are inherently hydrophilic and polymers are hydrophobic. Insufficient adhesion between natural fibres and polymer matrix results in poor mechanical properties. Natural fibers also absorb moisture over time which leads to debonding. These drawbacks of using natural fibers as reinforcement warrant use of surface treatment of fibers to improve adhesion between fiber and composite which results in better mechanical properties of natural fiber reinforced composites. In this experimental investigation the injection molding process to fabricate Banana fiber composites on industrial scale has been investigated. Alkali treatment of fibers was done to improve interfacial bonding between banana fiber and PP matrix . Effect of using different percentage of MAHPP to improve the mechanical properties was studied. It was found that maximum value of tensile and flexural strength was obtained on incorporating 10 percent MAPP. Further addition of MAHPP leads to decrease in tensile and flexural strength. Morphological examination of fractured surface of tensile test specimen shows that interfacial bonding improves on alkali treatment and further improves by addition of MAHPP.