| Abstract
| - The heterogeneous atom transfer radical polymerization of methyl methacrylate using thecatalyst complex CuBr/1,1,4,7,10,10-hexamethyltriethylene tetramine (CuBr/HMTETA) wasundertaken under a number of conditions to elucidate the effects of key process variables. Itwas found that a 100-fold reduction in metal salt concentration, to 21 ppm in solution (metal tointiator = 0.01:1), reduced polymerization rates 3-fold. PMMA produced at these low concentrations had high initiator efficiencies (Ieff = 88%) and low polydispersisties (1.1). Decreasing metalsalt concentrations 1000-fold, to 2 ppm (Mt:I = 0.001:1), resulted in PMMA with controlledmolecular weights (Ieff = 96%) but high polydispersities (2.1). Polymerization rates above andbelow a metal concentration of 210 ppm were found to be proportional to the metal saltconcentration to the power of 0.05 and 0.37, respectively. Rates were found to increase withligand concentration to the power of 0.52. Stirring was found to increase polymerization ratesby 40%.
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