The effects of compatibilizers on the morphological, mechanical, and optical properties of biaxially oriented poly(Ethylene terephthalate)/syndiotactic polystyrene blend films

In this study, the effects of three different types of compatibilizers on the morphological, mechanical, and optical properties of poly(ethylene terephthalate) (PET) and syndiotactic-polystyrene (s-PS) (70/30, wt%) blends and biaxially oriented blend films of the two polymers were investigated. The morphological results of the PET/s-PS (70/30) blends revealed that when the 5 phr polystyrene-g-oxazoline (PS-g-OXA) was used as a compatibilizer, the domain size showed minimum. The mechanical studies of the PET/s-PS (70/30) blends showed that when 5 phr PS-g-OXA was used, increased tensile strength was obtained. The transmittance of the blend film showed the highest value (83.7%) for the biaxially oriented PET/s-PS (70/30) blend films with the PS-g-OXA (5 phr), compared with that of the blends without compatibilizer (70.8%), or with the styrene-co-maleic anhydride as a compatibilizer, at the wavenumber of 600 nm. The tensile strength of the biaxially oriented PET/s-PS (70/30) blend films also showed the highest value when PS-g-OXA (5 phr) was used as a compatibilizer. The morphological, optical, and mechanical results of the PET/s-PS (70/30) blends and biaxially oriented blend films of the two polymers showed that PS-g-OXA was the most effective compatibilizer, and that the optimum compatibilizer content was 5 phr.