Preparation and characterization of oligomeric terpolymers of styrene, methyl methacrylate and 2-hydroxyethyl methacrylate: A comparison of conventional and catalytic chain transfer

Abstract

Batch solution terpolymerizations of styrene, methyl methacrylate and 2‐hydroxyethyl methacrylate were carried out at 70°C in the presence of either dodecanethiol or bis[(difluoroboryl)diphenylglyoximato]cobalt‐(II) (COPhBF), to yield polymer products with a number average molecular weight of about 2 500. Conversion, molecular weight distribution and overall composition were monitored during the reaction, and the final products were investigated using differential scanning calorimetry and thermogravimetric analysis. It was found that the overall rates of polymerization do not differ significantly in the two systems, but that the molecular weight distribution of the polymer formed in the presence of the thiol becomes increasingly broader during the polymerization, whereas the COPhBF‐mediated polymerization produces a relatively uniform product during the course of the reaction. The polymer product formed with COPhBF was found to be slightly less thermally stable than the product formed by the thiol, which can be explained by the formation of unsaturated endgroups in the case of the former product.

High‐conversion catalytic chain transfer polymerization of methyl methacrylate

“…In a polymerization similar to experiment II, Kukulj et al16 obtained slightly increasing molecular weights. Heuts et al22 recently also reported a slight decrease in molecular weight in the terpolymerization of styrene, MMA, and 2‐hydroxyethyl methacrylate, but it is very hard to interpret these data in a straightforward way, as the presence of three monomers considerably complicates the system. Kowollik et al20 reported an experimentally determined decrease of 45% in M w going from 10 to 100% conversion.…”

“…Some other studies were mainly focused on the production of dimer at high catalyst concentrations and subsequent copolymerization with other monomers 14, 15. Most kinetic studies were carried out in the group of Davis and Heuts 16–22. For nearly all studies molecular weight distributions did not or hardly change with conversion, whereas a decrease, which would be expected according to the Mayo equation (1), was only observed experimentally by Kowollik et al20 Several explanations have been suggested like catalyst deactivation and catalyst–solvent interactions that change with conversion and compensate for a decrease in monomer concentration.…”

Catalytic Chain Transfer Copolymerization of Methyl Methacrylate and Butyl Acrylate

“…So far, most reports on the application of CCT to copolymerizations described the copolymerization of two CCT active monomers, like styrene‐MMA11–14 styrene‐( α ‐methylstyrene)15 and MMA‐butyl methacrylate 16–18. Both Bon et al19 and Heuts et al20 included the functional 2‐hydroxyethyl methacrylate in their co‐ and terpolymerizations, respectively. Only a few papers report on the copolymerization of a CCT active and a CCT inactive monomer.…”

Evolution of molecular weight distributions in the catalytic chain transfer polymerization of methyl methacrylate up to high monomer conversions

“…Most of these investigations dealt with molecular weight distributions (MWDs) generated at low and moderate overall monomer conversions. Only three studies partly investigated the effect of increasing conversion on the MWD 7, 10, 11. It is the aim of this investigation to model MWDs obtained in CCT polymerizations for high monomer conversions (via the program package PREDICI®11) and to compare the modeling results with corresponding experimentally obtained MWDs.…”

“…Only three studies partly investigated the effect of increasing conversion on the MWD 7, 10, 11. It is the aim of this investigation to model MWDs obtained in CCT polymerizations for high monomer conversions (via the program package PREDICI®11) and to compare the modeling results with corresponding experimentally obtained MWDs. One of the technically most important features of CCT polymerization is the fact that one can produce a high‐conversion polymer product in a continuously stirred tank reactor with the desired molecular weight and polydispersity with numbers and reaction conditions derived from low‐conversion experiments.…”