The Study On Terpolymer Of HPM/St/MA And Its Application In Epoxy Resin

With the development of high technology, the higher heat resistance of epoxy resin is in urgent need. The development of new polymeric heat-curing agent is a very effective way to improve the heat resistance of epoxy resin. A new type of N-(4-hydroxyphenyl) maleimide/styrene/maleic anhydride terpolymer(HPM/St/MA) was designed, synthesized and applied to the modification of epoxy resin as a heat curing agent in order to improve the heat resistance of epoxy resin.With N-(4-hydroxyphenyl) maleimide, styrene, maleic anhydride as raw materials,1,4-dioxane as the solvent, azobisisobutyronitrile as initiator, HPM/St/MA terpolymer was synthesized by solution polymerization. Single factor experiments were designed to get optimized synthesis conditions.The results are as follows, reaction temperature is353K, reaction time is4hours, the amount of initiator concentration is1%of the total monomer concentration, the total monomer concentration [HPM÷St÷MA]=1mol/L,the monomer molar ratio of HPM:St:MA=l:2:1,and the yield of product is up to95%under the conditions.The structure of the copolymer was characterized and confirmed by FTIR; The content of each monomer in the terpolymer were confirmed by elemental analysis and anhydride determination methods, providing an experimental basis for the subsequent applications of terpolymer in epoxy resin; The thermal properties of synthetic terpolymer were investigated by the thermal analysis technique, the results show that the heat resistance of HPM/St/MA terpolymer(monormer ratio=1:2:1)has a significantly improvement compared with styrene/maleic anhydride (monormer ratio=2:1),and the maximum weight loss temperature is34K higher than styrene/maleic anhydride; The thermal stability of HPM/St/MA terpolymer has an increasing trend with N-(4-hydroxyphenyl) maleimide increasing content in the terpolymer raw materials.The E-44epoxy resin which was modified with HPM/St/MA terpolymer (monormer ratio=1:2:1)in heat curing was studied in this paper. The thermal performance of E-44epoxy resin cured by HPM/St/MA terpolymer and other common heat curing modifiers were compared by thermal analysis.The results show that the HPM/St/MA terpolymer has better curing effect and higher heat resistance with the same activity content modifier. The solvent resistance of the cured samples ware tested. The results show that the cured E-44epoxy resin with HPM/St/MA has better solvent resistance.The thermal decomposition kinetics of the HPM/St/MA terpolymer and E-44epoxy resin cured with HPM/St/MA were studied respectively with Kissinger,Starink and F-W-O function approaches.The results show that thermal decomposition apparent activation energy of the HPM/St/MA are144.00,145.14and147.38kJ/mol respectively. The results obtained by the three methods are similar, but the Kissinger method has the largest correlation coefficient and a relatively small error. The pre-exponential factor of the HPM/St/MA is2.59×1010min-1calculated with Kissinger method. The thermal decomposition apparent activation energy of E-44epoxy resin cured are160.72,161.29and153.73kJ/mol respectively. The results obtained by the three methods are also similar, but the Kissinger method has the largest correlation coefficient and a relatively small error. And the pre-exponential factor of the E-44epoxy resin cured is3.347X1011min-1calculated with Kissinger method.