基于异构联苯二酐的热塑性聚酰亚胺性能研究

制备了一系列基于异构联苯二酐[2,2’,3,3’-联苯四甲酸二酐(3,3’-BPDA)、2,3’,3,4’-联苯四甲酸二酐(3,4’-BPDA)和3,3’,4,4’-联苯四甲酸二酐(4,4’-BPDA)]的聚酰亚胺(PI)均聚物和共聚物,比较研究了这些聚合物的热学和力学性能。结果表明,当二胺结构相同时,基于3,3’-BPDA和3,4’-BPDA的PI均聚物或共聚物较基于4,4’-BPDA的均聚物有更高的玻璃化转变温度(Tg)和更好的热加工性;当二酐结构相同时,基于对苯二胺(PDA)的PI的Tg高于基于4,4’-二氨基二苯醚(ODA)的PI。基于3,4’-BPDA/PDA的PI具有最高的Tg,其值为382℃,由其制备的薄膜的拉伸强度为100 MPa,拉伸弹性模量为1.8 GPa,断裂伸长率为12%。基于4,4’-BPDA/PDA的PI薄膜具有最高的拉伸性能,其拉伸强度为307 MPa,拉伸弹性模量为4.1 GPa,断裂伸长率为23%。基于3,4’-BPDA/ODA和3,3’-BPDA/4,4’-BPDA(1/1)/ODA的PI模塑料均具有高于300℃的Tg和较好的力学性能,其冲击强度分别达到82.3 kJ/m2和94 kJ/m2。

Properties Study of Thermoplastic Polyimides Based on Isomeric Biphenyl Dianhydrides

A series of homopolyimides and copolyimides based on isomeric biphenyl dianhydrides[2,2’,3,3’-biphenyltetracarboxylic dianhydride(3,3’-BPDA),2,3’,3,4’-biphenyl tetracarboxylic dianhydride(3,4’-BPDA) and 3,3’,4,4’-biphenyltetracarboxylic dianhydride(4,4’-BPDA)] were prepared,then the thermal and mechanical properties of the polyimides were studied comparatively.The results showed that when the structures of diamine were same,polyimides based on 3,3’-BPDA and 3,4’-BPDA had higher glass translation temperature(Tg) and better thermo-processability than those derived from 4,4’-BPDA,when the structures of dianhydride were same,Tg of polyimides based on para-diamine(PDA) was better than that of polyimides based on 4,4’-diaminodiphenyl ether(ODA).Polyimide based on 3,4’-BPDA/PDA showed the highest Tg of 382℃,the tensile strength and modulus of the corresponding film was 100MPa and 1.8GPa respectively,and the elongation at break was about 12%.Film made from polyimide based on 4,4’-BPDA/PDA had the best tensile properties,the tensile strength was 307MPa,the tensile modulus was 4.1GPa,and the elongation at break was about 23%.Polyimide moulding plastics based on 3,4’-BPDA/ODA and 3,3’-BPDA/4,4’-BPDA(1/1)/ODA had Tg above 300℃ and better mechnical properties,the impact strength of them were 82.3kJ/m2和94kJ/m2 respectively.