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以异构的联苯二酐(BPDA)、二苯醚二酐(ODPA)以及2-苯基-4,4′-二氨基二苯醚(p-ODA)为原料,通过一步法或两步法,合成了一系列异构聚酰亚胺,并表征了这类聚酰亚胺的溶解性、热性能和力学性能。结果表明:基于p-ODA的聚酰亚胺在有机溶剂中具有优异的溶解性;基于p-ODA的异构聚酰亚胺都是非晶结构,且聚酰亚胺的溶解性和玻璃化温度(Tg)呈现3,3′-位>3,4′-位>4,4′-位的趋势,聚合物Tg>250℃。聚合物4,4′-ODPA/p-ODA具有较优的热稳定性,5%热失重温度(T5%)=551℃,聚合物3,4′-ODPA/p-ODA和4,4′-ODPA/p-ODA具有相似的机械性能。异构BPDA/p-ODA系列聚酰亚胺具有相似的热稳定性,T5%>550℃,聚合物4,4′-BPDA/p-ODA的机械性能优异,薄膜拉伸强度为182.4MPa、模量为3.5GPa、断裂伸长率为44.2%。
Using isomeric biphenyldianhydride (BPDA), diphenyl ether dianhydride (ODPA) and 2-phenyl-4,4’-diaminodiphenyl ether (p-ODA) as raw materials, Method, a series of isomeric polyimides were synthesized and the solubility, thermal and mechanical properties of these polyimides were characterized. The results show that the polyimide based on p-ODA has excellent solubility in organic solvents; the isomeric polyimides based on p-ODA are all amorphous structures, and the polyimide’s solubility and glass transition temperature (Tg) exhibits a tendency of 3,3’-position> 3,4’-position> 4,4’-position, and polymer Tg> 250 ° C. The polymer 4,4’-ODPA / p-ODA has better thermal stability, 5% weight loss temperature (T5%) = 551 ° C, polymer 3,4’-ODPA / p-ODA and 4,4 ’ -ODPA / p-ODA has similar mechanical properties. Heterogeneous BPDA / p-ODA series of polyimide has similar thermal stability, T5%> 550 ℃, polymer 4,4’-BPDA / p-ODA excellent mechanical properties, tensile strength of the film 182.4MPa, The modulus is 3.5 GPa and the elongation at break is 44.2%.