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

Uncompatibilized and compatibilized (polypropylene grafted maleic anhydride as compatibilizer) polyethylene terephthalate (PET)/polypropylene (PP)/TiO 2 microfibrillar composites (MFC) were prepared by injection molding of the pelletized PET/PP/TiO 2 drawn strands. The morphology of PET fibrils and the distribution of TiO 2 particles in the composites were examined. After injection molding the preferential location of TiO 2 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 TiO 2 particles results in decrease of both tensile strength and impact strength of the composites. However, the compatibilized PET/PP/TiO 2 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/TiO 2 MFC and the T g of PP in the compatibilized PET/PP/TiO 2 MFC are elevated by about 2°C. The elevation of T g is attributed to the preferential location of TiO 2 particles in the composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009