PLA/PBAT拓扑扩链体系的发泡性能

Foaming Properties of PLA/PBAT Topological Chain Extension System

为探究生物可降解材料的流体性能及其发泡性能,以异氰尿酸三缩水甘油酯(TGIC)和3,3',4,4'-联苯四羧酸二酐(BPDA)为扩链剂,通过双螺杆挤出机对聚乳酸(PLA)/聚己二酸对苯二甲酸丁二酯(PBAT)共混体系进行了反应性挤出改性,系统研究了共混流体改性前后的流变性能和发泡性能。结果表明,单一TGIC的加入可以使得体系的黏度、储能模量、损耗模量等性能均得到提升,发泡性能得以改善;而单一BPDA加入与分子链端羟基反应产生新的羧基基团,容易导致分子链发生降解,使得体系的黏度及流变性降低;当同时加入BPDA与TGIC对体系进行改性时,BPDA促进了TGIC与聚酯分子链的反应,复合流体表现出支化分子的流体特性,其储能模量和损耗模量比单一加入一种扩链剂时更好,相应流体的发泡性能也得以改善。

In order to explore the fluid properties and foaming properties of biodegradable materials,polylactide(PLA)was blended with poly(butylene adipate-co-terephthalate)(PBAT)using a twin screw extruder with the addition of triglycidyl isocyanurate(TGIC)and 3,3',4,4'-biphenyl tetracarboxylic anhydride(BPDA)as chain extenders.The synergistic effects of the two additives on the rheological properties and foaming properties of the PLA/PBAT blend were investigated.The results show that the addition of single TGIC can improve the viscosity,storage modulus,loss modulus and foam performances of PLA/PBAT composite.However,the reaction between BPDA and the terminal hydroxyl groups of the molecular chain could produce new carboxyl groups,leading to degradation of the molecular chain and decreases the viscosity and rheology of PLA/PBAT.When BPDA was added together with TGIC,the reaction between TGIC and polyester molecular chain could be promoted,and the composite melt shows characteristics of branched molecules,energy and loss modulus are better than only a single chain extender,and the foaming properties of the corresponding melt were thus improved.