Abstract
AbstractThe radical polymerizations and copolymerizations of dimethylstannyl dimethacrylate (DSM) and trimethylstannyl methacrylate (TSM) in dimethylformamide (DMF) were studied. These monomers did not polymerize thermally, but easily underwent polymerization in the presence of α,α′‐azobisisobutyronitrile and on irradiation with ultraviolet light. The polymer obtained from TSM was soluble in DMF and methanol, but that from DSM was insoluble in any organic solvents; this polymer probably consists of a network structure. These polymers were converted to poly(methyl methacrylate) (PMMA) by means of acid hydrolysis and then methylation with diazomethane. The content of syndiotactic triad was determined from infrared spectra of PMMA derived from the polymers of DSM and TSM. It was noted that the content of syndiotactic triad was greater in the radical polymerization of TSM than those of DSM at every temperature investigated. The differences in the activation enthalpy (ΔΔH‡) and in the activation entropy (ΔΔS‡) between isotactic and syndiotactic additions were determined as follows: for DSM, ΔΔH‡ = ∼0 cal/mole, ΔΔS‡ = −0.856 eu; for TSM, ΔΔH‡ = 229 cal/mole, ΔΔ = −1.09 eu. From the radical copolymerizations of DSM and TSM with styrene at 60°C, the copolymerization parameters, Q and e, were evaluated as follows: for DSM, Q = 1.36, e = 0.41; for TSM, Q = 0.45, e = −0.37. These results were compared with the reported effects of stannic chloride and zinc chloride on the radical polymerization of methyl methacrylate.
Published Version
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