Catalytic Synthesis And Properties Of High Molecular Weight Poly(Butylene Succinate)

Traditional plastics products that have brought us convience in the manufacturing and life brought about the increasing seriousness of“white polution”.Therefore, to develop the all-biodegraded materials that both satisfy the using requirements and the need of environmental protection has caused high attention of researchers. PBS, a biodegradable material, can be degraded into the CO2 and H2 O after it is deserved that does no harm to the environment.With excellent melt processability and thermal and chemical resistance,PBS becomes one of the most promising biodegradable materials. High molecular weight polyesters are an essential request for producing materials with appropriate processability and acceptant mechanical properties.And catalyst plays a critical role in the polycondensation reaction. Therefore,to select an excellent catalyst for the synthesis of PBS and prepare a heterogeneous catalyst which can be recycled are of significance to the PBS with higher molecular weight, the reduction of product cost and avoidance of the environment pollution.Poly(butylene succinate)(PBS) was synthesized from 1, 4-succinic acid and 1,4-butanediol by direct melt polycondensation method. The catalytic properties of several catalysts(SnCl2、Sn(Oct)2、ZnCl2、Zn(OAc)2、Sb2O3、SO42-?ZrO2)which were commonly used to catalyze the synthesis of poly(butylene succinate) were compared to select the most excellent catalyst through comparative experiments. Then, the catalytic process of homogeneous catalyst SnCl2 was optimized. At last,Sn2+were distributed on the attapulgite to prepare heterogeneous catalyst and investigated its catalytic effect. Intrinsic viscosity measurements were carried out by using an Ubbelohde viscometer to calculate the number average molecular weight to investigate catalytic mechanism of polycondensation reaction and reaction rate. The Fourier Transform Infrared spectoscopy(FT-IR), a rotational viscometer, wide angle X-ray diffraction(XRD), TGA, DSC are used to research the catalytic performance of attapulgite-supported Sn complexes and the acidolysis degradation of samples was also investigated.The results show that:1) SnCl2 is the most excellent homogeneous catalyst whose the optimum amount is1.5 wt.% of SA and the molecular weight is 11.2×103. The polycondensation reaction rate of polycondensation with SnCl2 as catalyst increased sixfold comparing to that of polycondensation without catalyst.2) When the polycondensation time was 5 hours, the molecular weight of PBS with Sn2+/AT as catalyst is 23.0×103and the polycondensation reaction rate is 58.08g·mol-1·min-1, increased 8.4 fold comparing to that of polycondensation without catalyst.3) the optimum amount of Sn2+/AT is 3 wt.% of SA.4) Under the same polymerization conditions,the PBS obtained with catalyst will get increasing molecular weight, smaller grain size,reducing the degree of crystallinity, betterthermal properties, slower rate of acidolysis degradation.