Study of multi-monomer melt-grafting onto polypropylene in an extruder

摘要

Free-radical melt-grafting of the dual-monomer systems glycidyl methacrylate-styrene (GMA-St) and hydroxyethyl methacrylate-styrene (HEMA-St) onto polypropylene (PP) has been studied using a single-screw extruder. For single monomer grafting systems, degradation of PP was unavoidable and deterioration of the mechanical properties of the grafted PP subsequently occurred because of #beta#-scission of PP chains during the free-radical melt-grafting process. However, for the dual-monomer systems, it is shown that the addition of styrene as a comonomer can significantly enhance the GMA or HEMA grafting levels on PP and reduce the extent of #beta#=scission of PP backbone. It has been found that the grafting dicumyl peroxide concentrations. Moreover, the melt flow rate of the dual-monomer grafted PP is smaller than that of th unmodified PP. Hence, PP not only was endowed with higher polarity, but also kept its good mechanical properties.