Browsing by Author "Cameron, G. Gordon"

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    Solvent Effects on the Free Radical Polymerization of Styrene
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1973, 69 (2), 1973) Burnett, George M.; Cameron, G. Gordon; Joiner, Sheila N.
    The free radical polymerization of styrene in various solvents has been studied. Using the rotating sector technique at 25°C rate coefficients for termination kt and propagation Ap were deter mined. The linear decrease of the former with decreasing medium fluidity shows that termination is diffusion-controlled. Values of kp decrease as the solvents used arc increased in concentration. A similar trend in Ap is observed when polymerization is initiated thermally at 60°C. The solvent effect on kt is similar to that previously recorded for methyl methacrylate, but solvents such as benzonitrile and diethyl malonatc diminish Ap of styrene while they enhance Arp for methyl metha crylate.
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    Stability Constants of Some Complexes of t-Butyl Mesityl Nitroxide
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1973, 69 (5), 1973) Burnett, George M.; Cameron, G. Gordon; Cameron, James
    Stability constants for complex formation of t-butyl mesityl nitroxide with various solvents and monomers have been determined in the range 25-85 C by gas-liquid chromatography and a spectrophotometric method. In general, molecules with extensive conjugation form the most stable complexes but diethyl malonate provides a notable exception. Solvents which form the most stable complexes show the strongest effects on the rate coefficients of propagation in radical polymerization of methyl methacrylate and styrene. This correlation supports the view that a proportion of the active macroradicals are complexed with monomer or solvent.