Study On The Synthesis And Properties Of Poly(Butylene Succinate) Series

Based on the synthesis of poly(butylene succinate)(PBS) with direct esterification and melting polycondensation, pure poly(ethylene succinate)(PES), pure poly(butylene adipate)(PBA), pure poly(butylene terephthalate)(PBT) and several co-PBS such as PBES, PBSA and PBST had been synthesized by adding aliphatic comonomers ethylene glycol(EG), adipic acid(AA) and aromatic comonomer terephthalic acid (TPA). An unreported ever and new odd number carbon aliphatic polyester-poly (propylene glutarate)(PPG) had also been studied.Nuclear magnetic resonance (NMR) was used to characterize the structure of different proportions of copolyesters. The results showed that the feeding molar ratio and actual component ratio of copolyesters were very similar.The synthesis conditions of various polyesters were compared and intrinsic viscosity was tested. The polycondensation reaction time of PBS was100min, and the intrinsic viscosity of PBS was the largest. The reaction time of PBSA was about100min, and the intrinsic viscosity of PBSA was higher. With the increasing of comonomers content, the reaction time of PBES and PBST was increased and the intrinsic viscosity decreased.DSC was used to test the melting point of the polyesters. It showed that the Tm of PBS was114.85℃. The Tm of PBES and PBSA decreased with increasing comonomer content. When the molar ratio of SA and TPA was from9:1to6:4, the Tm of PBST was lower than PBS. But when the molar ratio of SA and TPA was5:5, the Tm of PBST was119.65℃.By the TG-DTA test, the thermal weight loss of PBES and PBSA was similar to PBS, and PBA was superior to PBS. With the increasing of TPA, the thermal weight loss of PBST was gradually better. In the tested samples, the melt crystallization temperature was70.84℃and the other copolyerters were lower than PBS.By the test of capillary rheometer, it showed that the shear viscosity of tested samples decreased when the shear rate increased. And at the’same shear rate, the shear viscosity of copolyesters were lower than pure PBS.Poly (propylene glutarate) was synthesized by1,5-glutaric acid and1,3-propylene glycol through direct esterification and melting polycondensation with tetrabutyl titanate as the catalyst. The synthesis conditions were as follows:the molar ratio of glutarie acid and propylene glycol was1:1.1, the esterification temperature was170～230℃and the esterification time was40min, the polycondensation reaction temperature was250℃and the catalyst used in a mass amount1%of glutaric acid. The polycondensation reaction time was the shortest, just90min and the intrinsic viscosity could reach1.136dL/g. By the FTIR test, the synthetic product was proved to be expected PPG.