Free radical polymerization of methyl methacrylate up to the glassy state. Rates of propagation and termination

The free radical polymerization of methyl methacrylate in bulk at 0 deg C initiated by photochemical decay of azobis(cyclohexanenitrile) (ACN) is tested over the full range of conversion up to the glassy state. Rate constants of propagation, k sub p , and termination, k sub t , are evaluated by the...

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Bibliographic Details
Published in:Macromolecules 1988-12, Vol.21 (12), p.3345-3352
Main Authors: Sack, Regina, Schulz, Guenter Victor, Meyerhoff, Guenther
Format: Article
Language:English
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Summary:The free radical polymerization of methyl methacrylate in bulk at 0 deg C initiated by photochemical decay of azobis(cyclohexanenitrile) (ACN) is tested over the full range of conversion up to the glassy state. Rate constants of propagation, k sub p , and termination, k sub t , are evaluated by the rotating sector technique and after effect. Instantaneous degree of polymerization and efficiencies, f, are given for all conversions. The conversion dependence of f can be expressed by the self-diffusion of small molecules in a polymer matrix. Both rate constants depend on the conversion; k sub t for conversions near and beyond the onset of entanglement also depends on the chain length of the polymer radicals, but becomes independent of this length at approx 45% conversion. The diffusion processes describing the different stages of conversion are discussed. 19 ref.--AA
ISSN:0024-9297
1520-5835
DOI:10.1021/ma00190a001