Study On The Epoxy Matrix Used For Wet Pre-impregnating Filament Winding Technology

Epoxy resin system for wet pre-impregnating filament winding that has long-term chemical stability is prepared by adding nano SiO₂,acetylacetone-lanthanide transition-metal complex, silane coupling agent and methyl tetrahydrophthalic anhydride(MeTHPA)to the epoxy resin matrix and vigorously stirred to obtain the homogeneous solution.In this study,the temperature thixotropic phenomena of the resin system is investigated and the formula for resin system for wet pre-impregnating and wet filament winding at different temperature resistant grade is provided.Besides,mechanical and heat resistant properties of castable resin system are analysed.The temperature thixotropic phenomena of the resin system is investigated by using FT-IR and SEM.Experimental results show that the system is of gel state at room temperature because of the strong intermolecular interaction by hydrogen bonds,which were formed between SiO₂ and SiO₂ dispersing in epoxy resin matrix,or SiO₂ and the hydroxyl group on the surface of epoxy resin.Therefore,when the temperature arrives at or beyond the thixotropic temperature, the intermolecular hydrogen bonds are destroyed and the system changed from gel state into sol state.The formula and preparing technology of resin matrix under different temperature resistant grade are studied.The results show that in the grade of 130℃,bisphenol A-based epoxy resin E-51/MeTHPA system can be used,and the compounding ration is as follows(the quality of epoxy resin is 100%,the quality ratio is as follows):E-51 epoxy resin is 100%,MeTHPA is 70%,nano SiO₂ is 10%,silane coupling agent KH-550 is 2%,and acetylacetone-lanthanide transition-metal complex is 1%.In the temperature resistant grade of 160℃,trifunctional epoxy resin TDE-85/anhydride system was used,and the quality ratio is:TDE-85 epoxy resin is 100%, MeTHPA is 115%,nano SiO₂ is 15%,silane coupling agent KH-550 is 2.5%,and acetylacetone-lanthanide transition-metal complex is 1%.The preparing process is that metal complex was dissolved in epoxy resin at 85℃,then the anhydride and coupling agent were added when the temperature dropping at 65℃.After obtaining the homogeneous solution,nano SiO₂ were added into the solution from time to time,stirred about three hours and cooling down to room temperature. Whether the epoxy resin/imidazole complex system satisfied the fundamental requirements of the epoxy resin system for wet pre-impregnating filament winding was discussed initially. The results show that the resin system using imidaxole metal complex as curing agent is of long-term chemical stability.But,the temperature thixotmpy effect can't bc made by mixing nano SiO₂.Mechanical properties of TDE-85 epoxy resin/methyl tetrahydrophthalic anhydride/nano SiO₂ system are tested.Results are that flexural strength is 141.13MPa and flexural modulus is 4.12GPa.