Abstract: Polypropylene (PP) was melt grafted with styrene (St) and m-isopropenyl-α, α-dimethylbenzyl isocyanate (m-TMI) which has unsaturated bonds and isocyanate group. The grafted products were characterized using non-aqueous titrations, infrared spectrum, thermogravimetry and differential scanning calorimeter. It was found that both m-TMI and St were grafted onto PP. St inhibited effectively the degradation of PP during the grafting and improved the thermal stability of grafted products. At given concentration of St, the grafting degree and grafting efficiency of m-TMI increased at first and then slightly decreased with increasing m-TMI concentration; At given concentration of m-TMI, the grafting degree of m-TMI reached a maximum at St/ m-TMI of 1.6.

Key words: m-isopropenyl-α, α-dimethylbenzyl isocyanate, styrene, polypropylene, grafting