CHDA改性PBT的制备及其结构与性能研究

Preparation and structural properties of CHDA modified PBT

以精对苯二甲酸(PTA)、1,4-丁二醇(BDO)和1,4-环己烷二甲酸(CHDA)为原料,通过直接酯化法制得CHDA改性聚对苯二甲酸丁二醇酯(PBT)共聚酯,研究了CHDA含量对改性PBT共聚酯的结构和性能的影响。结果表明:随着CHDA含量的增加,改性PBT共聚酯的缩聚时间延长,特性黏数提高;CHDA的加入对改性PBT共聚酯的熔点、熔融结晶峰温度、结晶度的影响较大,当CHDA质量分数为20%,改性PBT共聚酯的熔点降至190.68℃,熔融结晶峰温度降至140.49℃,结晶度降至17.42%;改性PBT共聚酯的热稳定性略低于常规PBT,当CHDA质量分数为20%,改性PBT共聚酯的热分解峰值温度降至399.25℃;随着CHDA含量的增加,改性PBT共聚酯的拉伸强度、弯曲强度降低,断裂伸长率、冲击强度升高,当CHDA质量分数为5%~10%时,改性PBT共聚酯的综合性能较优,拉伸强度为40.65~44.11 MPa,断裂伸长率为143.23%~218.85%,冲击强度为5.12~5.88 kJ/m^(2),弯曲强度为45.15~51.31 kJ/m^(2)。

Using purified terephthalic acid(PTA),1,4-butanediol(BDO)and 1,4-cyclohexanedicarboxylic acid(CHDA)as raw materials,CHDA modified polybutylene terephthalate(PBT)copolyesters were obtained through direct esterification.The effect of CHDA content on the structure and properties of the modified PBT copolyesters was studied.The results showed that the condensation time of modified PBT copolyester was prolonged and the intrinsic viscosity increased with the increase of CHDA content;the addition of CHDA had a significant impact on the melting point,melting crystallization peak temperature and crystallinity of modified PBT copolyester,and the melting point of modified PBT copolyester decreased to 190.68℃,the melting crystallization peak temperature decreased to 140.49℃and the crystallinity decreased to 17.42%when the mass fraction of CHDA was 20%;the thermal stability of modified PBT copolyester was slightly lower than that of conventional PBT,and the thermal decomposition peak temperature of modified PBT copolyester dropped to 399.25℃when the mass fraction of CHDA was 20%;and the tensile strength and bending strength of modified PBT copolyester decreased,the elongation at break and impact strength increased with the increase of CHDA content,and the comprehensive performance of modified PBT copolyester was excellent,with a tensile strength of 40.65-44.11 MPa,elongation at break of 143.23%-218.85%,impact strength of 5.12-5.88 kJ/m^(2) and bending strength of 45.15-51.31 kJ/m^(2),when the mass fraction of CHDA was 5%-10%.