Dual-curing propargyl/phthalonitrile monomers for composites by vacuum infusion process

摘要

Four different bifunctional monomers were synthesized:two monomers containing N-propargylamine and phthalonitrile groups and two monomers containing O-propargyl ester and phthalonitrile groups.It was shown that only the latter one can be used to obtain composite materials by vacuum infusion(viscosity 40 mPa*s at 120 °C).The N-propargylamine containing monomers demonstrated high viscosity of the melts and degradation with allene evolution while curing.Carbon fiber reinforced plastics(CFRP)were successfully obtained from 4-[3-(prop-2-yn-l-yloxy)phenoxy]benzene-l,2-dicarbonitrile by a vacuum infusion molding process.Mechanical testing of the composites samples was performed.Influence of end-curing temperature on mechanical properties and morphology of composites was investigated.The curing temperature of 375 °C critically affects the properties of the composite due to the high shrinkage.Composites cured at 375 °C lost 18% of mechanical properties at 300 °C but cured at 330 only 10%.LOI for composites with a matrix of propargyl/phthalonitrile dual-curing polymers was equal to 75,which is higher than most materials obtained from thermosets.