Study on poly(butylene adipate-co-terephthalate)/starch composites with polymeric methylenediphenyl diisocyanate

To lower the cost of poly(butylene adipate-co-terephthalate) or PBAT, starch was used as a filler in this study. To increase tensile strength of PBAT/starch composites, polymeric methylenediphenyl diisocyanate (pMDI) was used as a compatibilizer. PBAT was melt-mixed with starch in a kneader, and then the mixtures were compression-molded. The effects of starch and pMDI content on the tensile strength and elongation at break of PBAT/starch composites were examined. The morphology and biodegradability of the composites in soil were also studied. The tensile strength of PBAT and PBAT/starch composites increases with increasing content of pMDI. The increase of weight average molecular weight of PBAT and improved interaction between PBAT and starch were observed with increasing content of pMDI. The weight average molecular weights of buried PBAT and the composites in soil significantly decrease. Especially, the reduction of the weight average molecular weight of PBAT/starch (70/30) composite is the most significant. (C) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41884.