| Different types of Polyurethane (PU) modified Diglycidyl Ether of Bisphenol-A (DGEBA) were prepared and tested, among which the most thermal stable one was applied to toughen R-122.The properties of PU prepolymer and the preparation methods were investigated to improve the performance of polyurethane modified E-51/Anhydride composite. Factors which would have influence on the mechanical properties such as kinds of multifunctional isocyanate, PPG molecule weight and polyurethane content etc. were evaluated by single factor experiments. Molecule structure, thermo mechanical properties and morphology was described by infrared spectrum, DTMA and SEM. Results indicates that when PU content is30PHR, Izod impact strength of IPN is20%higher than that of graft polymer modified resin, and has an increasement of150%compared to pure one. And Thermo gravimetric analysis showed that the thermo decomposition temperature of the composite would be improved when PAPI instead of MDI is employed.In addition to the properties, one compound epoxy potting resin was also prepared and studied. A in-situ polymerization is developed for the preparation of PU modified E-51/Anhydride by employing self-made latent accelerator, it could overwhelm the shortcoming of high viscosity and hard to dissolve in liquidized anhydride of PU cross-linked EP which occurred in presently reported preparation procedure. The storage period could be as long as20days, which, is longer than those had been reported according to foreign patent.And at the end of this issue, the most heat resistant PU/DGEBA matrix was used to toughen R-122epoxy resin. Results indicate that it could enable the polymer melt made from R-122and MA, which, according to traditional formula, would frozen at45℃, remains liquid at-10℃. And when the addition amount of PU/DGEBA was20%, it could have an increasement of150%in notched Izod impact strength compared to unmodified one. |
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