基于异构联苯二酐的热塑性聚酰亚胺性能研究

Properties Study of Thermoplastic Polyimides Based on Isomeric Biphenyl Dianhydrides

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。

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 100 MPa and 1.8 GPa 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 307 MPa, the tensile modulus was 4.1 GPa, 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 82.3 kJ/m^2 94 kJ/m^2 respectively.