Effects of temperature and impact modifier loading on impact properties of PLA
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Date
2016-06
Authors
Siti Hawa Azhar
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Abstract
Blending of core-shell impact modifier, CSIM in PLA has been conducted to improve its impact strength. The rubbery core is made up of polybutyl acrylate (PB) and the rigid shell is made up of grafted PMMA. The aim of this research is to investigate the effect of impact modifier loading and temperature on the impact properties of PLA. Neat PLA and PLA blends with loading of 5, 10, 15 wt % core-shell impact modifier were prepared through extrusion process. Impact sample of neat PLA and PLA/CSIM were prepared through compression molding. Prior testing, neat PLA and PLA/CSIM blends were conditioned at temperature of 30, 40, 50, 60 and 70⁰C for 30 minutes in an oven. Samples were subjected to impact testing with minimum delay upon removal from oven. Fractured surface of notched impact sample were then subjected to scanning electron microscope to study its morphology and mode of deformation. From impact testing, neat PLA shows the lowest impact strength at 30⁰C. Significant improvement in impact strength has been observed in neat PLA as temperature approach 60⁰C. The highest impact strength were obtained in blending of PLA with 15 wt% CSIM loading. The SEM of fractured surface shows an increase in crack path and roughness with increasing CSIM loading and temperature. From this research, it can be conclude that increasing loading of CSIM in PLA and temperature from 30 to 70⁰C improve the impact toughness of PLA.