可生物降解脂肪-芳香族共聚酯的材料性能研究

采用稀土-钛催化剂,以1,4-丁二醇、己二酸和对苯二甲酸二甲酯为原料制备了含己二酸丁二醇酯(BA)和对苯二甲酸丁二醇酯(BT)单元的系列共聚酯(BA-co-BT)。采用GPC、DSC、流变仪等方法表征了BA-co-BT的相对分子质量、力学性能、热性能和流变性能。表征结果显示,对于含40%～60%(x)BT的BA-co-BT,在相对分子质量及其分布相近时,随BT含量的增加,BA-co-BT的热性能和韧性得到改善,玻璃化转变温度和熔点升高。BA-co-BT熔体的表观黏度随剪切速率的增加而降低,属剪切变稀的假塑性流体,且在低剪切速率下熔体表观黏度对温度更敏感。通过堆肥降解实验研究了BA-co-BT的生物降解性能。实验结果表明,含40%(x)BT的BA-co-BT具有良好的生物降解性。

Properties of Biodegradable Aliphatic-Aromatic Copolyesters

A series of copolyesters,poly(butylene adipate-co-butylene terephthalate)(BA-coBT) containing butylene adipate(BA) and butylene terephthalate(BT) units,were synthesized via condensation reaction of 1,4-butanediol,adipic acid and dimethyl terephthalate in the presence of a rare earth-titanium catalyst.The relative molecular mass,mechanical,thermal and rheological characteristics of the BA-co-BT series were characterized by means of GPC,DSC and rheometer.The results show that for the BA-co-BT series with 40%-60% mole fraction of BT,when both their relative molecular mass and the relative molecular mass distribution are close,the thermal properties and toughness of the copolyesters are improved and their melting points and glass transition temperatures rise with the increase of BT content.The rheological behavior of the copolyesters is very close to non-Newtonian fluid.The apparent viscosity decreases with increasing shear rate,and temperature obviously affects the apparent viscosity under low shear rate.The biodegradability of BAco-BT was studied by compost experiments.The results indicate that BA-co-BT series containing 40%(x)BT possess good biodegradation.