PBS离聚物作为成核剂对PET性能的影响

Effect of PBS Ionomer as Nucleating Agent on PET Properties

本文采用直接酯化-熔融缩聚的方法合成聚丁二酸丁二醇酯离聚物(iPBS),通过核磁共振谱仪(1 H NMR)和拉曼光谱仪(Raman)对其化学结构进行了表征。结构分析表明,iPBS分子主链中含有两种重复结构单元,证明为所设计的聚合物。同步热分析仪(TG)表明,聚对苯二甲酸乙二醇酯(PET)/iPBS复合材料的热降解温度均在350℃以上,随离子含量的增加而降低,残碳量逐渐增加;差示扫描量热仪(DSC)研究表明,随着离子含量的增加,PET/iPBS复合材料的熔点逐渐增大,非等温结晶能力逐渐变强,成核效率增加。通过偏光显微镜(POM)可以观察到,等温条件下PET/iPBS复合材料的成核位点多,晶核密度大,结晶速率快。广角X射线衍射分析(XRD)表明,随着iPBS的加入,PET与复合材料的曲线具有非常相似的峰形,具有一致的晶型。动态热机械分析(DMA)表明,低温区的储能模量随着iPBS中离子含量的增加而增大,玻璃化转变温度向高温区移动。

PBS ionomers(iPBS)were synthesized by direct esterification and melt polycondensation,and their chemical structures were characterized by nuclear magnetic resonance spectroscopy and Raman spectroscopy.The structural analysis shows that PBSi molecule main chain contains two repeated structural units for the designed polymer.The thermal degradation temperature of polyethylene terephthalate(PET)/iPBS composites is above 350℃,and decreases with the increase of ion content,while the residual carbon contents increase gradually.Differential scanning calorimeter(DSC)studies show that the melting point of PET/iPBS composites increases with the increase of ion content,the non-isothermal crystallization ability becomes stronger,and the nucleation efficiency increases.It could be observed by polarizing microscope(POM)that PET/iPBS composites have more nucleation sites,high density of crystal nuclei and fast crystallization rate under isothermal conditions.Wide-angle X-ray diffraction analysis(XRD)shows that with the addition of iPBS,the curves of PET and composite material have very similar peak shape and the same crystal shape.Dynamic mechanical analysis(DMA)shows that the energy storage modulus in low temperature region increases with the increase of ion content in iPBS,and the glass transition temperature moves to high temperature region.