Abstract:

In order to expand the application range of polyethylene terephthalate (PET), a third monomer is often introduced to change its properties. In this study, a series of copolyesters with different monomer contents were synthesized from spirocyclodiol (SPG) by transesterification melting polycondensation. Combining advanced polymer chromatography with multi-angle laser light scattering (APC-MALLS) was used to measure the molecular weight and molecular weight distribution. Meanwhile, the chemical structure of copolyester was studied by ¹H NMR and FTIR spectroscopy. The thermal and crystallization properties of copolyester were studied by DSC, TGA and XRD. The tensile properties of copolyesters were also tested. The results showed that the copolyester which met the number average molecular weight (M_n) and weight average molecular weight (M_w) requirements of fiber grade polyester was successfully synthesized with narrow molecular weight distribution. With the increase of the content of the third monomer, the glass transition temperature increased from 77℃ to 85℃, while the melting temperature decreased from 255℃ to 222℃. The thermal decomposition temperature did not change significantly and the crystallization property decreased.

Key words: polymerization, chromatography, crystallization, spiroglycol, polyethylene terephthalate

摘要：

为了扩大聚对苯二甲酸乙二醇酯（PET）的应用范围，常通过引入第三单体来改变其性能。本研究以螺环二醇（SPG）为原料，采用酯交换法熔融缩聚合成了一系列不同单体含量的共聚酯。采用超高效聚合物色谱-多角度激光光散射仪（APC-MALLS）联用分析了共聚酯的分子量与分子量分布，利用核磁氢谱（¹H NMR）、傅里叶红外光谱（FTIR）研究了共聚酯的化学结构，同时采用差示扫描量热仪（DSC）、热重分析仪（TGA）和X射线衍射仪（XRD）研究了共聚酯的热性能以及结晶性能，测试了共聚酯的拉伸性能。结果表明，成功合成了符合纤维级聚酯数均分子量（M_n）和重均分子量（M_w）要求的共聚酯，分子量分布较窄，随着第三单体含量的增加，玻璃化转变温度从77℃提升至85℃，而熔融温度从255℃降低至222℃，热分解温度无明显变化，结晶性能下降。

关键词: 聚合, 色谱, 结晶, 螺环二醇, 聚对苯二甲酸乙二醇酯