超临界二氧化碳环境下PET聚酯的物理性能分析

 以PET(对苯二甲酸乙二醇酯)为对象,研究了超临界二氧化碳状态下体系温度和压力对原料物理性能的影响.通过TA Universal Analysal 2000热分析仪(DSC)表征样品的玻璃化转变温度(t_g),熔点(t_m)和结晶度;通过自动黏度测定仪表征样品的特征黏度();通过红外光谱仪(FT-IR)分析样品结构变化情况.结果表明,在超临界温度为130 ℃、超临界压力为20 MPa时,样品的t_g、t_m、最低,结晶度从原料的28%降到了23%,能使CO₂最大量地分析扩散进入材料中,最适宜溶胀发泡.红外表征结果表明样品分子结构没有变化,说明超临界CO₂没有与PET发生化学反应,物理参数变化由CO₂扩散进入材料分子链中引起的结晶度的变化而产生.

Analysis of PET polyester physical properties in supercritical CO2 environment

The PET(Polyethylene terephthalate) as the object of study,in supercritical carbon dioxide environment,the influence of system pressure and temperature on the raw material physical properties was studied.And samples glass transition temperature(tg),melting point(tm),crystallinity,characteristic viscosity(η]),molecular structure were characterized by TA Universal Analysal 2000(DSC),automatic viscosity locator,FT-IR.The results showed that when the supercritical temperature is 130 ℃ and supercritical pressure is 20 MPa,samples’ tg,tm,η] have minimum value.At the same time,the crystallinity of samples the lowest,which is droped from 28% to 23% compared with raw material.So there is more CO2 could diffuse into PET,it is to the benefit of foam PET.FT-IR characterization result showed sample molecular structure did not change,that supercritical CO2 and PET haven’t chemical reaction,physical parameters change is due to CO2 diffuse into molecules chain caused the change of crystallinity change.