Synthesis and characterization of the biodegradable copolymers from succinic acid and adipic acid with 1,4-butanediol

Biodegradable homopolyesters such as poly(butylene succinate) (PBSU) and po ly(butylene adipate) (PBAD) and copolyesters such as poly(butylene succinat e-co-butylene adipate) (PBSA) were synthesized, respectively, from succinic acid (SA) and adipic acid (AA) with 1,4-butanediol through a two-step proc ess of esterification and deglycolization. The polyester compositions and p hysical properties of both homopolyesters and copolyesters were investigate d by H-1- and C-13-NMR, DSC, GPC, WAY-D, and optical polarizing microscopy. The melting point (T-m) of these copolyesters decreased gradually as the c ontents of butylene adipate increased and the glass-transition temperature (T-g) of these copolyesters decreased linearly as the contents of the adipo yl unit increased. PBSA copolyesters showed two types of XRD patterns of PB SU and PBAD homopolyesters. Furthermore, the biodegradation and hydrolytic degradation of the high molecular weight PBSU homopolyester, PBAD homopolye ster, and PBSA copolyesters were investigated in the composting soil and NH 4Cl aqueous solutions at a pH level of 10.6. (C) 2001 John Wiley & Sons, In c.