Continuous controlled radical polymerization of methyl acrylate with copper wire in a CSTR

Abstract

The controlled radical polymerization of methyl acrylate in DMSO mediated by copper wire in a continuous stirred tank reactor (CSTR) was successfully demonstrated. Copper wire proved to be an easy to handle and reusable catalyst source, mediating chain growth through the SET-LRP mechanism. Polymerizations were conducted at 30 °C for three different residence times at varying copper surface area and ligand concentration. Doubling the available copper surface area led to an approximately 30% increase in polymerization rate at the same residence time, in agreement with published literature. Experiments conducted at low ligand concentration showed only a slight drop in polymerization rate with no adverse effect on molecular weight control. Chain extensions were conducted using methyl acrylate to simulate a second polymer block; no significant dead chain fraction was observed, indicating that the polymer produced retained living characteristics. The life time of copper wire as a catalyst source was estimated from experimental data on copper consumption rates. Deviation from expected polydispersities and the effects of utilizing two CSTRs in series on the molecular weight distribution are discussed.