Study On Synthesis Of Polymide Including Oxazole And The Structure Thereof Properties

The synthesis and performances of PI including oxazole were studied in this term.The synthesis of 2,6-Di(p-aminophenyl)benzo-[1,2d;5,4d′]-bisoxazole (diam -ine) was studied by designing orthogonal experiments and the effect factors on the reaction were analysed, then optimal synthesis conditions of diamine were confirmed. 2,6-Di(p-aminophenyl)benzo-[1,2d;5,4d′]-bisoxazole was synthesized with 4 ,6-diaminoresorcinol dihydrochloride and 4-aminobenzoic acid in the polyphosphoric acid systerm. The product was characterized by IR, 1HNMR, EA and the structure accorded with the target product. The thermal properties of diamine were determined by DSC and TG obtaining good thermal properties.Synthesis of Polyamic acid(PAA) was studied by viscosity. In the reaction of synthesizing with 2,6-Di(p-aminophenyl)benzo-[1,2d;5,4d′]-bisoxazole and BODPA, the effects of time, temperature, mole ratio and the percentage of water in the system on the viscosity of PAA were studied and the optimal conditions were determined. Diamine and dianhydride dissolved into DMAc with the mol ratio of 1:1.02 and reacted for 40h under 5℃after removing water in reactant and solvent, obtaining PAA solution with major viscosity being 1.7dL/g.2,6-Di(p-aminophenyl)benzo-[1,2-d;5,4-d′]-bisoxazole reacted with different acid anhydrides, gaining relevant PAA solution. PMDA-PI, BPDA-PI and BODPA-PI were prepared with PAA. Viscosity of PAA was tested and solubility of PI was tested in different solvents. then the effects of structures of PI on molecular weight and solubility were analysed. The result indicated that the stronger inflexibility was, the lower molecular weight was, and higher the viscosity was. Td, melting-decomposing temperature and Tg were tested individually by TG, DTA, DSC .Results showed that the thermal properties of PI including oxazole were more excellent than conventional PI, and and the stronger inflexibility was, the better thermal properties were.Calculated by Flynn-Wall-Ozawa method the activation energy of heat decomposition of BOPDA-PI was 110.79 kJ/mol. The kinetic parameters of heat-decomposition reaction of BOPDA-PI were determined by differential calculus...