Effect of Alkali Treatment of Alstonia macrophylla (AS) fiber on Dynamic Mechanical and Machinability Properties of Polypropylene (PP) Composites reinforced with Unidirectional AS fiber

Dynamic mechanical analysis (DMA) and drilling performance of the polypropylene (PP) composites reinforced with different volume fractions (0, 10, 20, 30, 40 and 50 vol.%) of untreated and alkali treated novel Alstonia macrophylla (AS) fiber were investigated. DMA reports showed that 40 vol.% fiber loaded PP composites imparted good thermomechanical properties in terms of storage modulus (E'), and loss modulus (E") with a remarkable 366% and 331% improvement than virgin PP laminates respectively. In addition, study also disclosed that, alkali treated composites exhibited higher DMA properties than untreated PP composites owing to strong interfacial bonding of fiber and matrix as result of alkali treatment. Drilling study was also performed to investigate the effect of chemical treatment and drill parameters viz., drill point angle (90 & DEG;, 118 & DEG;, and 130 & DEG;) and feed rate (20, 40, and 60 mm/min) on machinability property of PP/AS composites. Drilling outcomes conveyed that alkali treated PP/AS composites showed slight resistance to drilling than untreated composites owing to strong interfacial strength which played a vital role in resisting thrust force. Field emission scanning electron microscopy (FESEM) was used to capture the images of the drilled surface to understand the morphology of the PP/AS composite.