基于生物基异山梨醇的高耐热共聚酯的合成与表征

Synthesis and Characterization of High Heat-resistant Copolyester Based on Bio-based Isosorbide

采用直接酯化工艺制备了生物基异山梨醇(ISB)与间苯二甲酸(IPA)协同共聚改性的聚对苯二甲酸1,4-环己烷二甲醇酯(PICTA),研究了当IPA单元含量为15 mol%时,ISB结构单元含量对PICTA共聚酯性能的影响,目的是开发出无定形高耐热共聚酯。采用采用核磁共振氢谱(^(1)H-NMR)、差示扫描量热仪(DSC)、X射线衍射仪(XRD)与热重分析仪(TGA)表征了PICTA共聚酯的分子结构、热性能、结晶性能与热降解性能。研究结果表明:ISB结构单元含量每增加1 mol%,PICTA共聚酯的玻璃化转变温度线性增加约0.8℃。当ISB结构单元含量升高至25.4 mol%,经过180℃高温退火10 h的PICTA共聚酯样品趋近于无定形状态,这说明ISB共聚单元的引入可显著抑制PICTA共聚酯的结晶能力。此外,TGA研究结果表明,PICTA共聚酯具有良好的热稳定性,初始热分解温度高于405℃,但ISB共聚单元的存在并不会改变共聚酯的热分解机理。

Poly(1,4-cyclohexanedimethanol terephthalate)modified by synergistic copolymerization of bio-based isosorbide(ISB)and isophthalic acid(IPA),which is called PICTA in this study,was prepared by direct esterification process.The effect of ISB unit content on the properties of PICTA copolyester was studied when the IPA unit content was 15 mol%,in order to develop an amorphous high heat-resistant copolyester.The molecular structure,thermal properties,crystalline properties and thermal degradation properties of PICTA copolyester were investigated using nuclear magnetic resonance hydrogen spectroscopy(^(1)H-NMR),differential scanning calorimeter(DSC),X-ray diffractometer(XRD)and thermogravimetric analyzer(TGA).The results showed that the glass transition temperature of PICTA copolyester increases linearly by about 0.8℃ for every 1 mol%increase in the unit content of ISB.When the proportion of ISB copolymerization increased to 25.4 mol%,the PICTA copolyester samples annealed at 180℃ for 10 h tended to be in an amorphous state,which indicated that the introduction of ISB copolymerization units could significantly inhibit the crystallization capability of PICTA copolyesters.In addition,the results of TGA study showed that the PICTA copolyester had good thermal stability and the initial thermal decomposition temperature was higher than 405℃,but the presence of ISB copolymerization units did not change the thermal decomposition mechanism of the copolyester.