节点文献
线型饱和聚酯与共聚酯的合成及性能研究
Studies on the Synthesis and Properties of Linear Saturated Polyesters and Copolyesters
【作者】 黄关葆;
【导师】 武荣瑞;
【作者基本信息】 四川大学 , 材料学, 2003, 博士
【摘要】 本文在相同实验条件下,合成了含不同组成单元的线型饱和脂芳族均聚酯(聚对苯二甲酸乙二醇酯,PET;聚对苯二甲酸丙二醇酯,PTT;聚对苯二甲酸丁二醇酯,PBT;聚间苯二甲酸乙二醇酯,PEI:聚萘二甲酸乙二醇酯,PEN)及含不同共聚组分的PET系共聚酯(含IPA的PEIT;含NDA的PENT以及含PEG的PEET),对比研究了它们的酯化及酯交换反应动力学、缩聚反应动力学,得到了相应的动力学参数(反应速度常数及反应活化能),具有较好的规律性,并从分子结构的角度进行了解释。说明随着脂肪二元醇中亚甲基数目的增加,都使得反应速度降低;随着芳香二酰基空间位阻的增大,也使得反应速度降低,反应活化能增大。其中,关于PTT合成的直接酯化和缩聚反应的动力学研究、关于PEI合成的酯化和缩聚反应动力学研究,关于PEN合成的酯化和缩聚反应动力学研究的结果(活化能数据),至今尚未见文献报道 对所得的均聚酯和共聚酯都进行了转变温度测试,并研究了它们的结晶性能和流变性能。结果指出,IPA的引入,破坏了PET大分子的规整性,使PEIT的玻璃化温度降低,熔点显著降低,冷结晶温度升高,当IPA含量达一定程度时,PEIT不再结晶;刚性较大的NDA的引入,使PENT的玻璃化温度和冷结晶温度都升高,熔点则降低;柔性PEG链的引入,使PEET的玻璃化温度和冷结晶温度都降低,熔点稍有降低。 用DSC法研究了均聚酯从熔体降温的等温结晶动力学和非等温结晶动力学,结果表明,PBT、PTT的结晶速度常数最大,PEN的结晶速度常数最小,PET的结晶速度常数介于它们之间,而PEI不结晶。这一结果与DSC法测得的均聚酯转变 四{!}大学博士学位论文2003届温度结果中Tc的变化规律是一致的。 用解偏振光法对共聚酷的结晶速度进行了研究,指出具有空间位阻的工PA和具有空间位阻并有更大刚性的NDA的引入,使共聚酷的结晶速度降低,且随添加量的增多,共聚醋的结晶速度降低越多。柔性PEG链的引入,使共聚酷的结晶速度加快,且随PEG含量增多,结晶速度加快越多。这一结果也与DsC法测得的共聚酷转变温度结果中Tc的变化规律是一致的。 流变性能的研究结果表明,PET、PTT、PBT的粘流活化能相近,含刚性蔡环的PEN的粘流活化能最大,PEI的粘流活化能则居中间。对于共聚酷来说,随着工PA、NDA含量的增加,PEIT、PE附的粘流活化能增大,PEET的粘流活化能随PEG含量和添加量而变,但受PEG的分子量的影响更明显。
【Abstract】 A Series of linear saturated fatty-aromatic homo-polyesters (Polyehtylene terephthalate, PET; Polytrimethylene terephthalate, PTT; Polybutylene terephthalate, PBT; Polyethylene isophthalate, PEI; Polyethylene-2,6-naphthalate, PEN) and co-polyesters (PEIT, PENT, PEET) have been synthesized under the same conditions. The kinetics have been studied and compared, and the activation energies have been obtained for the esterification, ester-exchange reaction, and polycondensation. It has been shown that with the increase of secondary methyl(-CH2-), the rates of the reactions above decrease. The activations energies for esterification of TPA and PDO, IPA and EQ NDA and EQ and the activation energies for the polycondensation of PTT, PEI, PEN have not been reported on literature up to now.The study results of transition temperatures have shown that: the homo-polymer of PEI is not crystalline; with IPA leading into the macromolecules, the glassy transition and melting temperatures of PEIT decrease, the cold crystallization temperature of PEIT increases; with NDA leading into the macromolecules, the glassy transition and cold crystallization temperatures of PENT increase, the melting temperature of PENT increases; with PEG leading into the macromolecules, the glassy transition temperature, the cold crystallization temperature and the melting temperature of PEET all decrease.The isothermal and non-isothermal crystallization of homo-polyesters by themethod of DSC have shown that: the crystallization of PTT and PBT is fastest, that of PEN is slowest. The crystallization rates of co-polyesters with depolarized method have shown that with the quantities increase, IPA makes PEIT crystallization slowly, NDA makes PENT crystallization slowly, PEG make PEET crystallization quickly.Rheology results have shown that the rheological activation energies(En) of PET, PTT, PBT are quite similar, the En of PEI is bigger, and of PEN is the biggest. For copolyesters, with the increases of IPA and NDA contents, the rheological activation energies(E,) of PEIT and PENT all increase. The rheological activation energies(Ea) of PEET mainly depends on the molecular weights of PEG