Preparation of PBS-g-IAH and the effect on the performance of PLA/PBS composite

Abstract

Polylactic acid (PLA) and poly(butylene succinate) (PBS) are thermodynamically incompatible systems, and usually require the addition of compatibilizers or chain extenders to improve their compatibility. In this paper, PBS grafted itaconic anhydride (IAH) (PBS-g-IAH) was prepared by melt grafting method with diisopropylbenzene peroxide (DCP) as initiator and was used as the compatibilizer to prepare PLA/PBS-g-IAH/PBS composite. FTIR and Raman spectroscopy were used to characterize the grafting products. The effects of the dosages of DCP and IAH on the grafting rate of PBS-g-IAH were investigated. The results of FTIR and Raman spectroscopy showed that IAH had been successfully grafted onto the PBS molecular chains. When the amounts of DCP and IAH were 0.4% and 10% of the PBS mass, respectively, the product achieved the highest grafting rate of 1.46%. The crystallization properties, micro-morphology, rheological properties, mechanical properties, and heat resistance of the composites were investigated by DSC, SEM, rotary rheometer, electronic tensile testing machine, impact testing machine and Vicat softening temperature tester. The results showed that as the grafting rate of PBS-g-IAH was 1.30% and the mass fraction was 5%, the composite exhibited the best comprehensive properties, and the elongation at break was increased from 235.5% to 381.4% compared with that without PBS-g-IAH. The impact strength was increased from 4.4 kJ/m² to 5.9 kJ/m² and the softening temperature was increased from 72.5℃ to 129.4℃. According to the DSC analysis, the T_g of PLA/PBS blends decreased from 54.4℃ to 46.7℃ when the mass fraction of PBS-g-IAH was 5%. The SEM images showed that PBS-g-IAH had a good compatibilizing effect on PLA/PBS blend.