Methacrylic copolymers with a hydroxyl group on one end of the main chain and nona-1-butoxytrititanosiloxane as side groups (called methacrylic hybrid copolymers) were synthesized for use as baked-finish-type coating resins. The chemical structures of the side groups in the methacrylic hybrid copolymers were confirmed with the ash weight of the copolymers after combustion, the elemental ratio analysis of Si and Ti in the ash determined by inductively coupled plasma emission spectrometry, and the characteristic absorption band determined by Fourier transform infrared spectrophotometry. The methacrylic hybrid copolymers were cured at temperatures less than 150 degreesC in the absence of a curing accelerator. The cured copolymers exhibited a high thermal stability. The curing temperature of the copolymers was determined by the change in the absorption peak strength (peak area) of the 1655 cm(-1) band in the IR difference spectrum. The thermal stability of the copolymers was evaluated as the thermal-degradation temperature measured by thermogravimetric analysis. The methacrylic hybrid copolymers were then be used as effective curing resins. The mixture, consisting of thermoplastic methacrylic terpolymer with hydroxyl and carboxyl groups and the methacrylic hybrid copolymers, were cured at less than 150 degreesC in the absence of a curing accelerator and exhibited a higher thermal-degradation temperature than the copolymers. (C) 2001 John Wiley & Sons, Inc.