端羟基超支化聚酯的改性及性能研究

以三羟甲基丙烷和二羟甲基丙酸为原料，在对甲苯磺酸催化下合成了端羟基超支化聚酯，8-4′-丙氧基（1，1-联苯）-氧]-辛酸为封端剂对超支化聚酯进行改性，采用羟值滴定确定封端率。通过红外光谱（FT-IR）和核磁共振谱(NMR)对改性前后超支化聚酯的化学结构进行了表征，并采用差示扫描量热法（DSC）和广角X射线衍射（WAXD）对所合成超支化聚合物的热性能进行了研究。结果表明，封端剂的最佳用量为聚合物中羟基物质的量的1.05倍，在此条件下，超支化聚合物封端率达到92.02%；改性前后聚合物化学结构与理论结构一致，改性后聚合物玻璃化温度显著升高，且聚合物物相由无定形态转变为晶态与非晶态共存。

Study on modification and properties of a hydroxyl-terminated hyperbranched polyester

A hyperbranched polyester has been synthesized by a pseudo-one-step procedure based on trimethylolpropane and dimethylolpropionic acid as raw materials, modified by 8-［4′-propoxy (1,1-biphenyl)-4-yloxy］-octanoic acid. The end-capping ratio was determined by titration of hydroxyl groups. The chemical structures of the polymers were identified by FT-IR and NMR, and the thermal properties were investigated by DSC and WAXD. The results showed the optimal dosage of end capping reagent was 1.05 times the amount of hydroxyl groups in the hyperbranhced polymer. Under this condition, the end capping ratio was 92.0% and the chemical structures of the polymers were consistent with their theoretical structures. The glass transition temperature (Tg) of the polymer was significantly increased after modification and the polymer was converted an from amorphous phase to a mixture of crystalline and amorphous phases after modification. 