Study of PET/PP/TiO2 microfibrillar‐structured composites,Part 2: Morphology and mechanical properties

Uncompatibilized and compatibilized (polypropylene grafted maleic anhydride as compatibilizer) polyethylene terephthalate (PET)/polypropylene (PP)/TiO₂ microfibrillar composites (MFC) were prepared by injection molding of the pelletized PET/PP/TiO₂ drawn strands. The morphology of PET fibrils and the distribution of TiO₂ particles in the composites were examined. After injection molding the preferential location of TiO₂ particles is still preserved. Because of the reinforcement effect of PET fibrils, the tensile properties and impact strength of the PET/PP MFC are improved compared with the pure PP. Incorporation of TiO₂ particles results in decrease of both tensile strength and impact strength of the composites. However, the compatibilized PET/PP/TiO₂ MFC demonstrate better mechanical properties compared with the uncompatibilized ones. DMA analysis shows that the glass transition temperature (T_g) of PET in the uncompatibilized PET/PP/TiO₂ MFC and the T_g of PP in the compatibilized PET/PP/TiO₂ MFC are elevated by about 2°C. The elevation of T_g is attributed to the preferential location of TiO₂ particles in the composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009