The hydrosilylation of alpha,omega-bis(trirnethylsiloxy) methylhydridesiloxane (degree of polymerization approximate to 53) with acrylic and methacrylic acid with various ratios of the initial compounds, in the presence of platinum hydrochloric acid, has been investigated. In the presence of platinum hydrochloric acid, competitive dehydrocondensation reactions take place with the formation of various oligomers with various chemical links. In the later stages of the reaction, three-dimensional systems have been obtained. During dehydro-condensation, the reaction order, reaction rate constants, and activation energy have been determined. The structures of the synthesized oligomers have been determined with IR and NMR spectroscopy data. Gel permeation chromatography, differential scanning calorimetry, and X-ray analyses of the synthesized oligomers have been carried out. (c) 2006 Wiley Periodicals, Inc.