聚脲和聚酰亚胺的微波辐射合成

Synthesis of Polyureas and Polyimide by Microwave Irradiation

研究苯代三聚氰胺与2,4-甲苯基二异氰酸酯的微波辐射聚合及聚脲与均苯四酸二酐的微波固相聚合，考察了微波辐射时间（功率）、单体浓度、扩链剂和温度等因素对缩聚物的特性粘数、产率的影响，并与热聚合进行比较。用红外光谱对聚酰亚胺的亚酰化度进行了表征，首次用简并四波混频技术测量了缩聚物的三阶光学非线性极化率系数及其响应时间。实验结果表明：微波辐射对提高聚合物的特性粘数和产率有显著作用；合成的聚脲与聚酰亚胺具有较好的三阶光学非线性(聚脲的χ(3)=1.174×10－13esu)和较快的时间响应(24ps)。

Polyimide and polyureas with excellent physical and chemical properties were synthesized by a novel synthesis method of microwave irradiation. Solid state polycondensation of benzoguanamine and 2,4-tolylenediisocyanate, polyureas and pyromellitic dianhydride by using microwave irradiation were studied. In system of tolylendiisocyanate/benzoguanamine, the effect of microwave radiation time, concentrations of monomer and catalyst and temperature on the intrinsic viscosity of the obtained polymer and the conversion rate were studied. At the same time, the compare of microwave radiation polymerization with thermopolymerization was made. The imidization degree of polyimide was expressed by infrared absorption spectrum. The polycondensate's third-order optical nonlinearities and time responses were measured by picosecond forward three-dimensional degenerate four-wave mixing technique for the first time. The results showed that the intrinsic viscosity and the conversion of polymer are improved greatly by microwave radiation, the polyureas and the polyimide prepared have high third-order nonlinear optical coefficients ( PUχ(3)=1.174×10-13esu) and fast time responses(24ps).