Efficient Carbonyl Hydrosilylation Reaction: Toward EVA Copolymer Crosslinking

In this article, the hydrosilylation reaction of carbonyl groups of acetate derivatives and SiH groups of hydride-terminated polydimethylsiloxane at high temperature (100-130 degrees C) are described. Triruthenium dodecacarbonyl, Ru-3(CO)(12), was used as effective catalyst for hydrosilylation reaction. The hydrosilylation reactions with octyl acetate and 4-heptyl acetate were investigated by multinuclear NMR spectroscopy (H-1, C-13, and Si-29). This work provides evidence of the addition reaction of SiH groups onto carbonyl groups. The influence of the nature of the acetate structure on the reaction kinetics was shown and the slight contribution of side reactions at high temperature highlighted. Hydrosilylation reaction was extent to the crosslinking of ethylene-vinyl acetate (EVA) copolymer in the same range of temperature. The formation of EVA chemical network was demonstrated by HR-MAS NMR spectroscopy and by measuring the gel fraction of EVA chains in hot toluene. From Flory theory, the crosslinking density of elastic strand was calculated to be 80 mol m (3) in agreement with the measurements from swelling ratio (VA/SiH molar ratio: 11.8). (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 2899-2907, 2011