【摘要】 PET的固相缩聚是将低分子量预聚体加热到熔点和玻璃化温度之间,切片内部缩聚反应持续进行,分子量不断提高,乙二醇、水等副产物借助真空或惰性气体带出反应器.固相缩聚中包括酯化反应、酯交换反应以及小分子的扩散过程.表现反应速率受预聚体颗粒形状大小、结晶度、惰性气体、反应温度、反应时间等因素的影响,其中反应温度、惰性气体中小分子副产物含量是两个主要影响因素,应合理选择并控制这些参数,以利于生产出高质量的PET.更多还原

【Abstract】 Solid state polymerization of Poly (ethylene terephthlate)(PET) is carried out by heating the low molecular weight prepolymer at temperature below its melting point but above its glass transition temperature. Polycondensation occurs in the chips and the molecular weight continuously increase. The condensation byproducts such as ethylene glycol, water can be removed by applying vacuum or inert gas. Chemical reactions involved in the solid state polymerization are transesterification, esterification, as well as the diffusion of the byproducts. Overall reaction rate is affected by the molecular weight of prepolymer, crystallinity, partical geometry and size, inert gas, reaction temperature and time. Reaction temepature and byproduct concentration of the inert gas are the more important parameters . It is necessary to properly choose and control these parameters for producing high quality poly (ethylene terephthalate).更多还原