Macromers of 3-[tris(trimethylsilyloxy)silyl]-propyl methacrylate (TRIS) were synthesised using catalytic chain transfer polymerization, and the kinetic parameters governing the reaction were evaluated. A study on the radical solution polymerization of TRIS in the presence of the catalytic chain transfer agent bis[(difluoroboryl)dimethylglyoximato]cobalt(II) (COBF) at 60°C was conducted. Using appropriate Mark-Houwink-Kuhn-Sakurada constants for polyTRIS, the chain transfer constant (Cs) for COBF was found to be ∼1400 in toluene solution. This low Cs value, as compared to the value reported for methyl methacrylate polymerization (∼3.5 · 104), is only partly explained by a diffusion-controlled chain transfer reaction in the methacrylate series of monomers. A study on the influence of conversion on the molecular weight distribution indicated significant broadening and bimodality, consistent with reversible catalyst poisoning and chain transfer to the macromers. High oxygen solubility in TRIS is hypothesised to play a role in the reversible catalyst poisoning making it difficult to obtain a controlled reaction under normal free-radical polymerization reaction conditions.
|Number of pages||10|
|Journal||Macromolecular Chemistry and Physics|
|Publication status||Published - 20 Jun 2000|