PREPARATION OF A NOVEL HALS POLYPROPYLENE STABILIZER

The radiation induced graft copolymerization of m-isopropenyl-alpha,al pha-dimethyl benzyl isocyanate (m-TMI) and styrene onto polypropylene was carried out. The extent of grafting increased with increasing amou nt of styrene and with increased radiation dose. A graft load of 180% was obtained by immersing a 50 kGy pre-irradiated film in a monomer so lution containing 25 mol % m-TMI and 75 mol % styrene. The graft copol ymer is suitable for covalently binding nonpolymerizable stabilizers w ith a suitable nucleophilic moiety. In this work the isocyanate moiety of the graft copolymer was allowed to react with 4-amino-2,2,6,6-tetr amethyl piperidine, a hindered amine light stabilizer. Fourier transfo rmed infrared spectroscopy confirmed the formation of an urea moiety. (C) 1995 John Wiley & Sons, Inc.