Stereospecifity in radical polymerization of methyl α-(chloromethyl)acrylate

Poly(methyl α-(chloromethyl)acrylate)s (PMCMAs) obtained by homopolymerizations of methyl α-(chloromethyl)acrylate (MCMA) in benzene at different temperatures were converted to poly(methyl methacrylate)s (PMMAs) by reduction with tributyltin hydride. The reduction proceeded smoothly to yield PMMA exhibiting no 1H NMR resonance due to the CH2Cl group. The tacticity of the PMCMA obtained at 40 °C was determined using the 1H NMR resonances of the α-methyl group of PMMA derived: mm/mr/rr=8/56/36. Apparently, the propagation of MCMA preferred r addition to a lower extent in comparison with that of MMA. The more polar and the bulkier α-substituent ClCH2 (relative to CH3) would diminish the effect of the carbomethoxy group, thus resulting in a lower level of synditacticity than in MMA polymerization. The tacticity of MMA–MCMA copolymers estimated after conversion to PMMA varied from that of PMMA to that of PMCMA; an increase in MCMA content in the feed resulted in a decrease in rr content. Coisotactic parameters for copolymerization of MCMA with MMA-d8 were determined according to Hatadaʹs procedure for determination of these parameters [Polym J 19 (1987) 1105].