Effects of impurity contents in bio-based succinic acid on properties of biodegradable poly(butylenes succinic-co-butylene terephthalate)

Aliphatic-aromatic copolyesters, poly(butylenes succinic-co-butylene terephthalate) (PBTS), were synthesized via direct polycondensation from petroleum-based 1, 4-butanediol and terephthalic acid together with bio-based succinic acid (SA) with a rare earth compound as the catalyst. The effects of different SA and the contents of impurities derived from biological fermentation of SA preparation on the properties of PBTS were investigated. GPC was used to characterize the relative molecular weight and distribution of PBTS, and the results showed that the relative molecular mass significantly increased and its distribution became wider. The results indicate that the SA monomer with regular, loose and bigger particles size are preferable for the synthesis. The mechanical properties of PBTS lowered and PBTS turned to yellow due to the existence of organic acid and inorganic salt in the SA monomer.