复合催化剂合成可降解共聚酯PBAT及性能表征

Synthesis and properties characterization of degradable co-polyester PBAT using complex catalyst

通过钛酸四丁酯、正硅酸乙酯以及磷酸三乙酯的反应制备了一种复合催化剂,然后以1,4-丁二醇、己二酸和对苯二甲酸为原料,使用该复合催化剂通过直接酯化法合成了聚对苯二甲酸丁二醇-co-聚己二酸丁二酯(PBAT)。研究了酯化率、缩聚时间对合成的PBAT特性黏度的影响,重点对比了制备的复合催化剂与传统聚酯催化剂的活性。采用核磁共振、傅里叶变换红外光谱对聚合物的结构进行了表征。结果表明,当酯化率由80%增加至95%时,PBAT的特性黏度从0.95 dL/g增加到1.25 dL/g;随着缩聚反应时间的增加,PBAT的特性黏度先增加后减小,当缩聚时间为65 min时,PBAT的特性黏度达到最大,为1.25 dL/g。当制备的复合催化剂质量分数为0.025%时,PBAT的特性黏度可以达到1.1 dL/g以上,并且缩聚温度只需要240℃左右(传统的催化剂需要270℃以上),这大大降低了反应能耗。从熔融温度、结晶温度、拉伸断裂强度以及断裂伸长率等性能测试结果来看,采用自制复合催化剂合成的PBAT的结晶温度为84.75℃,拉伸断裂强度为26.2 MPa,断裂伸长率为870%,性能得到了更好的提升。

A complex catalyst was prepared through the reaction of tetrabutyl orthotitanate,ethyl orthosilicate and triethylphosphate,and the polybutylene terephthalate-co-polybutylene adipate(PBAT)copolyester was synthesized with the complex catalyst by direct esterification using 1,4-butanediol,adipic acid and terephthalic acid as raw materials.The effects of esterification ratio and polycondensation time on the intrinsic viscosity of the copolyester were investigated,focusing on the activity of the prepared complex catalyst in comparison with that of conventional polyester catalysts.The structure of the copolyester was characterized by nuclear magnetic resonance and Fourier transform infrared spectroscopy.The results show that the intrinsic viscosity of PBAT increases from 0.95 dL/g to 1.25 dL/g when the esterification ratio increases from 80%to 95%.The intrinsic viscosity of PBAT first increases and then decreases with the increase of the polycondensation time,and the intrinsic viscosity of PBAT reaches the maximum of 1.25 dL/g when the polycondensation time is 65 min.When the mass fraction of the prepared complex catalyst is 0.025%,the intrinsic viscosity of PBAT can reach more than 1.1 dL/g,and the required polycondensation temperature only is about 240℃(the required temperature for the traditional catalyst is more than 270℃),which greatly reduces the reaction energy consumption.From the performances test results of melting temperature,crystallization temperature,tensile breaking strength and elongation at break,the PBAT synthesized by the complex catalyst has a crystallization temperature of 84.75℃,a tensile breaking strength of 26.2 MPa,and an elongation at break of 870%,which show a better performance improvement.