聚己二酸丁二醇-co-聚对苯二甲酸丁二醇酯扩链改性研究

Study on modification of PBAT by chain extension

为了降低聚己二酸丁二醇-co-聚对苯二甲酸丁二醇酯(PBAT)的熔融指数,在双螺杆中,利用多元环氧扩链剂(ADR)对PBAT进行了扩链反应。基于正交实验对ADR扩链PBAT反应进行了研究,确定了影响反应的主要因素,并对扩链后的树脂进行了流变以及常规性能研究。结果表明,扩链剂浓度对扩链反应速率影响最大,反应温度次之。ADR扩链后,PBAT的分子结构产生了较大变化,形成了支化结构,分子链弹性增强,且扩链剂浓度越高,支化结构越明显。经过ADR扩链后,PBAT树脂的端羧基下降、特性黏度上升、熔融指数降低、熔融温度以及熔融结晶温度略有下降。

In order to reduce the melt flow index,polybutylene adipate-co-polybutylene terephthalate(PBAT)was modified by chain-extension reaction in a twin-screw extruder using a multifunctional epoxy chain extender(ADR).The orthogonal experiment was conducted to study the chain-extension reaction in order to determine the main factors.The results show that the concentration of the chain extender has the greatest effect on the chain-extension reaction rate,followed by the reaction temperature.Furthermore,the rotational rheology and conventional properties of the resin after chain extension were studied.It is found that after the chain-extension reaction,the molecular structure of PBAT has undergone major changes,forming a branched structure,and the elasticity of the molecular chain is enhanced,meanwhile,the higher the concentration of the chain extender,the more obvious the branched structure.After the chain-extension reaction,the terminal carboxyl group content of PBAT resin decreased,the intrinsic viscosity increased,the melt flow index decreased,the melting temperature and the melting crystallization temperature decreased slightly.