Effect of alkali treatment on thermal and mechanical properties of kenaf fiber/polylactic acid composites
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Date
2019-07
Authors
Nur Nabilah Binti Imtiaz Ahmad
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Abstract
This research project was carry out to investigate the effect of alkali treatment on thermal and mechanical properties of kenaf fiber/polylactic acid composites. The study of the thermal degradation and kinetic behaviour of kenaf fiber/polylactic acid composites involved determination of the activation energy using Flynn and Wall expression. Kenaf fibers used were untreated (UTKF) and also treated (ATKF) with 6% of sodium hydroxide (NaOH) for 3 hours. There were three samples produced which PLA, PLA/UTKF and PLA/ATKF. The composite samples of PLA/UTKF and PLA/ATKF were prepared with 40% fiber loading (based on weight). The samples were prepared by using internal mixer and compression moulding. Effect of alkali treatment on kenaf fiber and composites properties were investigated. Alkali treatment removed components such as hemicellulose, lignin, pectin, fat and wax that exposed cellulose and increased the roughness of the fiber surface to enhance the interfacial bonding between kenaf fiber and PLA matrix. The treated fiber surface was analysed by using Fourier-Transform Infrared (FTIR) spectroscopy and scanning electron microscope (SEM). Mechanical properties of the composites such as tensile test of composite were determined according to ASTM standard. The thermal degradation and kinetic behaviour of the composites were determined by using thermogravimetric analysis (TGA) and the activation energy was determined by using Flynn and Wall expression. In comparison between the composites, PLA/ATKF composite show high thermal and mechanical properties due to better interfacial adhesion between polylactic acid and kenaf fiber.