CORE-SHELL PARTICLES DESIGNED FOR TOUGHENING THE EPOXY-RESINS - II - CORE-SHELL-PARTICLE-TOUGHENED EPOXY-RESINS

The diglycidyl ether of bisphenol A-m-phenylene diamine (DGEBA-M-PDA) epoxy resin was toughened with various sizes and amounts of reactive c ore-shell particles (CSP) with butyl acrylate (BA) as a core and methy l methacrylate (MMA) copolymerized with various concentration of glyci dyl methacrylate (GMA) as a shell. Ethylene glycol dimethacrylate (EGD MA) was used to crosslink either core or shell. Among the variables of incorporated CSP indicated above, the optimal design was to obtain th e maximum plastic flow of epoxy matrix surrounding the cavitated CSP d uring the fracture test. It could be achieved by maximizing the conten t of GMA in a shell-crosslinked CSP, the particle size, and the conten t of CSP in the epoxy resin without causing the large-scale coagulatio ns. The incorporation of reactive CSP could also accelerate the curing reaction of epoxy resins. Besides, it was able to increase the glass transition temperature of epoxy resins if the particle size less than or equal to 0.25 mu m and the dispersion was globally uniform. (C) 199 8 John Wiley & Sons, Inc.