端苯基超支化聚酯对PET结晶行为和构象的影响

采用差示扫描量热法(DSC)和衰减全反射傅里叶变换红外光谱(ATR-FTIR)研究了不同代数和含量的端苯基超支化聚酯(HBP)对聚对苯二甲酸乙二醇酯(PET)结晶行为和构象的影响,计算了晶带与内标峰的吸光度比值以及左右式构象的相对含量.其中975 cm?1和1340 cm?1处的吸收峰归属于反式构象,1370 cm?1处归属于左右式构象,793 cm?1和873 cm?1处的吸收峰为内标峰.结果表明,6%的第三代超支化聚酯对PET的结晶促进能力最强.随着超支化聚酯含量或代数的增加,各吸光度比值基本上都呈现出先增大后减小的趋势,左右式构象的含量则表现出先减小后增大的趋势.端苯基超支化聚酯既可以充当成核剂,又可以充当结晶促进剂,因而可以促进PET结晶.

Effect of Phenyl-Terminated Hyperbranched Polyesters on Crystallization Behavior and Conformation of PET

The effects of generations and content of phenyl-terminated hyperbranched polyesters(HBP) on the crystallization behavior of poly(ethylene terephthalate)(PET) in PET/HBP blends were investigated by using differential scanning calorimetry(DSC) and attenuated total reflection—Fourier transform infrared spectrum(ATR-FTIR).The absorbance ratio of crystalline band and internal reference and the relative content of gauche conformation were estimated from the absorbances of the trans band at 975 cm 1 and 1340 cm 1,the gauche band at 1370 cm 1,and the internal standard band at 793 cm 1 and 873 cm 1.The results show that the crystallization ability of PET is the highest in the blend with 6 %(wt) of the third generation phenyl-terminated hyperbranched polyester.The absorbance ratio increases at first,then decreases with the increase of the content or the generation of HBP,and it shows the opposite with the increase of the relative content of gauche conformation.Phenyl-terminated hyperbranched polyesters play the role of nucleating agent and crystallization rate promoter for the crystallization of PET in the blends.