No abstract

A dimeric biradical 'Mi plays a central role in the initiation of the spontaneous polymerization of methyl methacrylate (MI). Besides the initiation step by chain transfer reaction, a change of the multiplicity of ' M; seems to be of importance. Evidence is given by heavy atoms in the solvent or in an inert gas atmosphere, leading to an acceleration of the overall polymerization rate. The observed effect is related to the atomic number of the respective heavy atom. Measurements of the temperature dependence of the effect for carbon tetrachloride show thatas expectedno activation energy is needed for this reaction step. The results are summarized in a reaction scheme for the initiation mechanism of the spontaneous polymerization of methyl methacrylate. C-CHZ-CH CH COOCH, COOCH, 2-I COOCH, COOCH, (HI) (HHI) Part 6: cf.@. Pressent address: Kalle, Niederlassung der Hoechst AG., D-6200 Wiesbaden-Biebrich. b, Part of the dissertation of J. L., Mainz 1982.0025-1 16X/84/$03.00 *) Thiophenol is an exception, the transfer effect of which is strong as compared to the heavy **) The authors want to express their thanks to the Rohm company for the generosity in atom effect to be expected (cf. discussion in6)).supplying unstabilized monomer of extremely high purity.

No abstract

No abstract