SOLID-PHASE GRAFTING OF GLYCIDYL METHACRYLATE ONTO POLYPROPYLENE

Free-radical grafting of glycidyl methacrylate (GMA) onto polypropylen e (PP) powder was studied in a batch mixer. The reaction temperature w as below the melting point of PP so that PP was modified in the solid phase. The graft yield of GMA obtained under various experimental cond itions allowed for a good appreciation of the effects of chemical para meters (the concentration of monomer, initiator, and interfacial agent ) and those of processing parameters (reaction time and temperature). Toluene was used as an interfacial agent to etch the surface of PP pow der to provide more sites for reaction. Quantitative determination of the graft level was performed by wet chemical methods. The results sho wed that the solid-phase grafting could take place over a temperature range of 100-140 degrees C in the initiation of benzoyl peroxide (BPO) . The ultimate GMA grafting level achieved was higher than that obtain ed in the melt state with dicumyl peroxide (DCPO) as a radical initiat or. The grafting of GMA affected the crystalline morphology of PP and speeded up the crystallization process. The energy of activation and i nitial decomposition temperature of grafted samples were higher than t hose of ungrafted PP. (C) 1997 John Wiley & Sons, Inc.