Synthesis and characterization of biodegradable poly (propylene terephthalate-co-propylene adipate) copolyester

A series of biodegradable aliphatic-aromatic poly(propylene terephthalate-co-propylene adipate)(PPTA) copolyesters were synthesized from 1,3-propanediol(1,3-PDO), dimethyl terephthalate(DMT) and adipic acid(ADP) with different mole ratios of DMT to ADP. The obtained PPT As were characterized by means of GPC, 1H NMR, WXRD, DSC and compost test. Compositions of PPTA copolyesters closely accorded with mole ratios of DMT to ADP. The sequence distributions of aliphatic segment(propylene adipate) and aromatic segment(propylene terephthalate) in main chains, crystalline structure, thermal properties and biodegradability of PPTA copolyesters closely related to the compositions. Therefore PPTA copolyesters with different properties can be tailored by controlling mole ratio of DMT to ADP. In addition, when mole fraction of ADP was in the range of 30%-80%, PPTA copolyesters with high biodegradability could be obtained. The biodegradability could be enhanced greatly by increasing ADP content within the range.