支化PET共聚酯的合成及其性能研究

Synthesis and Properties of Branched PET Copolyesters

摘要: 分别以丙三醇、三羟甲基乙烷和三羟甲基丙烷作为第三单体采用酯化–缩聚两步法合成了一系列支化PET共聚酯。并采用DSC、TG、力学分析和透光率以及阻隔性测试等手段对材料进行了表征。研究表明：低于1%含量的第三组分的加入会降低PET的熔点和玻璃化转变温度，但这并不影响PET加工中的稳定性，同时还能极大的改善PET的流动性，这对PET的加工带来了一些的便利；在力学性能测试中发现支化共聚酯较纯PET并没有发生太大的变化，可以基本满足材料的应用需求。当第三组分含量超过1%时，缩聚反应中，体系粘度急剧加快，后期产品无法进行二次加工。在阻隔性测试中发现，支化聚酯的阻隔性有部分提升。

Abstract: A series of branched PET copolyesters were synthesized by esterification-polycondensation two-step method using glycerol, trimethylolethane and trimethylolpropane as third-monomers, respectively. The materials were characterized by DSC, TG, mechanical analysis, light transmittance and barrier of oxygen and water. Study showed that the addition of third-monomers will reduce the melting point and glass transition temperature of PET, and greatly improve the flow of PET without reducing of stability, and could also greatly improve the flow of PET, which can provide some convenience in PET processing. In the mechanical performance test, it’s found that there was not too much changed between branched copolyesters and pure PET, which can basically meet the application requirements of the material. When the content of third-monomers exceeds 1%, the viscosity of the system increases sharply during the polycondensation reaction, and the later product cannot be processed by secondary processing. In the barrier property test, it was found that the barrier property of branched polyesters partially improved.