PET固相缩聚装置切片及粉尘结晶行为分析

采用差示扫描量热(DSC)方法研究了聚对苯二甲酸乙二酯(PET)固相缩聚工艺过程中切片及粉尘的结晶熔融及降温结晶行为,研究表明,切片与粉尘呈现出不同的结晶行为,切片随工艺过程的进行,特性黏度增加,降温结晶能力减弱;而粉尘特性黏度增加的幅度更大,降温结晶能力增强;预结晶及结晶粉尘因摩擦形成了更高熔融温度(267.5℃)下的结晶;高的无机杂质的浓度,促进了粉尘的降温结晶成核;粉尘高的结晶能力,易造成后产品加工过程形成结晶斑点。

Analysis of and Chips Powder Crystallization Behaviour from PET Solid State Polymerization Plant

The crystallinity melting and cooling crystallization of chips and its powders from different stages of polyethylene terephthalate(PET) solid state polymerization(SSP) process have been researched by using differential scanning calorimetry(DSC) method.It shows that chip and powder have different crystallization behaviour.With proceeding of the process,the intrinsic viscosity of chip increases and the cooling crystallization ability of it decreases,while powder has a larger intrinsic viscosity increase than chip and a increase of cooling crystallization ability.Both pre-crystallizer and crystallizer powder form crystallinity at high melting temperature(267.5 ℃) due to friction.The high content inorganic component acts as the nucleating agent and accelerates crystallization.The high crystallization ability of powder in chips may form the crystallization spot during downstream processing.