Synthesis of polyethylene hybrid copolymers containing polyhedral oligomeric silsesquioxane prepared with ring-opening metathesis copolymerization

Ring-opening metathesis copolymerizations of cyclooctene and the polyhedral oligomeric silsesquioxane (POSS) monomer 1-[2-(5-norbornen-2-yl)ethyl]-3,5,7,9,11,13,15-heptacyclopentylpentacyclo[9.5. 1.1.(3,9).1(5,15).1(7,13)] octasiloxane (POSS-norbornylene) were performed with Grubbs's catalyst, RuCl2(=CHPh)(PCy3)(2). Random copolymers were formed and fully characterized with POSS loadings as high as 55 wt %. Diimide reduction of these copolymers afforded polyethylene-POSS random copolymers. Thermogravimetric analysis of the polyethylene-POSS copolymers under air showed a 70 degreesC improvement, relative to a polyethylene control sample of similar molecular weight, in the onset of decomposition temperature based on 5% mass loss. The homopolymer of POSS-norbornylene was also synthesized. This polymer had a rigid backbone according to H-1 NMR evidence of broad olefinic signals. (C) 2001 John Wiley & Sons, Inc.