Study of polypropylene/polyethylene terephthalate blends compatibilized with polypropylene double-grafted maleic anhydride and epoxy resin

Polypropylene double-grafted maleic anhydride and bisphenol A epoxy resin (PP-g-M-E) was successfully prepared by a single-step method and characterized by Fourier-transform infrared spectroscopy. Subsequently, it was employed as a compatibilizer to fabricate polypropylene (PP)/polyethylene terephthalate (PET) blends via melt extrusion. The content of the PET dispersed phase in the composite varied from 0 to 30 phr. The microstructure and morphology of the composites were characterized using scanning electron microscopy and Raman spectroscopy. The addition of PP-g-M-E increased the interfacial interaction between the two phases and improved the compatibility and thermal stability of the system. In the presence of the compatibilizer, the crystallinity of the matrix phase (PP) increased, while that of the dispersed phase (PET) decreased owing to the heterogeneous nucleation effect of uniformly distributed PET. Double grafting of the PP-g-M-E compatibilizer considerably enhanced the mechanical performance of the PP/PET blend system. The elongation at break of the modified sample exceeded that of the PP/PET blends by 117.55%, and the flexural and impact properties also showed considerable improvement.