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采用二步法合成了以2,6-二(对-氨基苯)苯[1,2-d;5,4-d’]二噁唑和1,4-二(3,4-二苯氧基)苯四甲酸二酐(HQDPA)为单体的聚苯并双噁唑酰亚胺.该聚酰亚胺的预聚体聚酰胺酸的黏度为1.70 dL/g,经过热环化后能够生成浅黄色的聚酰亚胺薄膜.通过热重分析法研究了聚苯并双噁唑酰亚胺在N2气氛中的热降解机理.采用Flynn-Wall-Ozawa和Friedman法计算了聚苯并双噁唑酰亚胺热降解表观活化能,分别为356.36kJ/mol和370.54 kJ/mol,平均值为363.45 kJ/mol;反应级数为4.22,指前因子为6.44×1016s-1.采用Coast-Redfern法和Phadnis-Deshpande法研究了聚苯并双噁唑酰亚胺的热降解固相反应机理,认为该聚酰亚胺的热降解机理属于反曲线(A3)机理,是成核和增长模式(Avrami equation 2方程)控制的热降解反应,积分形式为g(X)=[-ln(1-X)]3.
A two-step method was used to synthesize 2,6-di (p-aminobenzene) benzene [1,2-d; ) Pyromellitic dianhydride (HQDPA) as a monomer, the polyamic acid of the polyimide prepolymer has a viscosity of 1.70 dL / g and is capable of being subjected to thermal cyclization And a yellowish polyimide film was formed.The thermal degradation mechanism of polybenzobisoxazole imide in N2 atmosphere was studied by thermogravimetric analysis.Using Flynn-Wall-Ozawa and Friedman method, The apparent activation energy of oxazole imide was 356.36kJ / mol and 370.54kJ / mol, respectively, with an average value of 363.45 kJ / mol. The reaction order was 4.22 and the pre-exponential factor was 6.44 × 1016s-1. -Redfern method and Phadnis-Deshpande method were used to study the mechanism of thermal degradation of polybenzobisoxazole imide. The thermal degradation mechanism of polyimides belongs to the anti-curve (A3) mechanism, which is the nucleation and growth (Avrami equation 2) control the thermal degradation reaction, the integral form of g (X) = [- ln (1-X)] 3.