This work reports the homo- and copolymerization behavior of previously unknown 4-diamantyl methacrylate (DMA) with vinyl comonomers like methyl methacrylate (MMA); the starting monomer DMA was synthesized in our laboratory using 4-diamantanol and methacryloyl chloride. The structures of the homo- and copolymers were analyzed using NMR techniques. DMA was found to be more reactive than MMA during copolymerization. The reactivity ratios as determined by the Kelen-Tudos method are r(MMA) = 0.58 and r(DMA) = 1.75. The incorporation of a few mol % of diamantyl units into the PMMA backbone led to a significant increase in its thermal stability and glass transition temperature. The polymers with 15 and 42 mol % of DMA units in the copolymers showed increased T-g values of 126 degrees C and 172 degrees C, respectively. (C) 2009 Wiley Periodicals, Inc. I Appl Polym Sci 114:2109-2115, 2009