不同软段长度聚醚酯弹性体PEGT/PBT的合成与表征

用熔融缩聚法合成一系列基于聚乙二醇对苯二甲酸酯（PEGT）/聚对苯二甲酸丁二醇酯（PBT）的聚醚酯热塑性弹性体，以NMR，IR，DSC及力学性能测试等方法表征材料的结构及性能，讨论相同硬段长度下，不同软段长度对材料性能的影响，结果表明，随组分中段长度增加，其质量分数升高，软，硬段相分离趋势增强，软段熔点及结晶度增加而玻璃化转变温度降低，相反，硬段玻璃化转变温度及熔点则分别保持在326K及459K附近基本不变，其结晶度则随硬段含量降低而降低，材料弹性模量，抗拉强度，屈服应力降低，而断裂延伸率增加。

Synthesis and Characterization of Polyether Ester Elastomer Based on Poly(Ethylene Glycol Terephthalate) and Poly (Butylene Terephthalate) with Different Soft Segment Length

A series of polyether ester thermoplastic elastomers based on poly(ethylene glycol terephthalate) (PEGT) and poly (butylene terephthalate) (PBT) have been synthesized and characterized by means of NMR, FTIR, DSC and mechanical testing. The influence of different soft segment length on the copolymer properties was investigated with invariable hard segment length. It was observed that, firstly, there coexist four phases corresponding to the amorphous and the crystalline phase of soft and hard segments in some compositions; secondly, the glass transition temperature (T g) of the soft segment PEGT decreased, and its molten point (T m) as well as the degree of crystallinity increased with the increase of its number-averaged molecular mass, at the same time, T g and T m of the hard segment changed slightly in the vicinity of 326 K and 459 K, respectively, while the degree of crystallinity of the hard segment decreased; thirdly, the drop in the inherent viscosity after molten moulding showed that the copolymer was prone to thermooxidative degradation. All the copolymers were distinguished by a high elastic and plastic deformation and were broken at very high relative deformations. The increase of PEG molecular weight in the composition shifted the stress-strain curves from the one with neck-formation characteristics to the one with typical high elastic state. Thus the elastic modulus, tensile strength and yield stress as well as the relative elongation at break were seen to have changed accordingly.