The copolymerization reactions of 2-(dimethylamino)ethyl methacrylate (DMAEMA) with methyl methacrylate (MMA), butyl methacrylate (n-BMA), methyl acrylate (MA), and butyl acrylate (n-BA), respectively, by an environmentally stable palladium acetylide Pd(PPh3)(2)(C = CPh)(2) (PPP) have been investigated. PPP shows relatively high catalytic activity for these copolymerizations. Reactivity ratios of these copolymerizatins have been measured and calculated by the Kelen-Tudos method for the first time, and their values are as follows: (1) r(DMAEMA) = 1.13. r(MMA) = 1.07; (2) r(DMAEMA) = 0.77, r(n-BMA) = 0.84; (3) r(DMAEMA) = 1.54, r(MA) = 0.09; (4) r(DMAEMA) = 0.71, r(n-BA) = 0.14. The mechanism of these copolymerizations was discussed and a radical mechanism was proposed. (C) 2004 Elsevier Ltd. All rights reserved.