Thermal properties of bio flour-filled polypropylene bio-composites with different pozzolan contents

In this study, the thermal properties of bio-flour-filled, polypropylene (PP) bio-composites with different pozzolan contents were investigated. With increasing pozzolan content, the thermal stability, 5% mass loss temperature and derivative thermogravimetric curve (DTG(max)) temperatures of the bio-composites slightly increased. The coefficient of thermal expansion (CTE) and thermal expansion of the bio-composites decreased as the pozzolan content increased. The glass transition temperature (T (g)), melting temperature (T (m)) and percentage of crystallinity (X (c)) of the bio-composites were not significantly changed. The thermal stability, thermal expansion and X (c) of the maleic anhydride-grafted PP (MAPP)-treated bio-composites were much higher than those of non-treated bio-composites at 1% pozzolan content due to enhanced interfacial adhesion. X-ray diffraction (XRD) analysis confirmed the crystallinity of pozzolan-added bio-composites. From these results, we concluded that the addition of pozzolan in the bio-composites was an effective method for enhancing the thermal stability and thermal expansion.