Free‐radical polymerization of methyl methacrylate initiated by N,N‐dimethylaniline

Abstract N,N‐Dimethylaniline (DMA) does initiate the free‐radical polymerization of methyl methacrylate (MMA), methyl acrylate, and methyl vinyl ketone. The overall rates of polymerization of MMA were obtained at 40, 50, and 60°C. From the results of a detailed kinetic investigation, the activation enthalpy and activation entropy of polymerization were calculated as 63,2 kJ mol−1 and −153 J mol−1 K−1 at 60°C. Rate equation was also obtained as Rp = k[DMA]1/2[MMA]3/2 and the polymerization was inhibited by benzoquinone. Though styrene alone was not polymerized by DMA, the copolymerization of MMA with styrene by DMA (reactivity ratios: rMMA=0,45 and rSt=0,50) followed a typical free‐radical mechanism. An electron‐transfer complex between DMA and MMA is proposed as the initiation species.