Free‐radical polymerization of methyl methacrylate with a tetrafunctional peroxide initiator

Abstract

This study examined the use of a new tetrafunctional peroxide initiator in the bulk free‐radical polymerization of methyl methacrylate. The objective was to investigate the effect of using a multifunctional initiator through an examination of the rates of polymerization and the polymer properties. The molecular weights and radii of gyration were obtained with a size exclusion chromatograph equipped with an online multi‐angle laser light scattering detector. The performance of the tetrafunctional initiator was compared to that of a monofunctional counterpart [tert‐butylperoxy 2‐ethylhexyl carbonate (TBEC)]. The results showed that the new tetrafunctional peroxide initiator produced a faster rate of polymerization than TBEC at an equivalent concentration but also generated a polymer of a lower molecular weight. This trend was the opposite of what was observed in a previous study with styrene. When TBEC was used at a concentration four times that of the new tetrafunctional peroxide initiator, both produced equal rates of polymerization and similar molecular weights. The degree of branching was also investigated with radius‐of‐gyration plots. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5647–5661, 2004

Recent Advances in the Study of Multifunctional Initiators in Free Radical Polymerizations

“…Other systems that were examined include the copolymerization of MMA and α‐methylstyrene where depropagation reactions readily occur;30 the polymerization of butyl acrylate whose high rates of transfer to polymer produce branched chains and eventually gel material;31 and the polymerization of vinyl acetate where transfer to monomer and polymer reactions dominate 31. As well, selective experiments were completed for the copolymerization of styrene and methyl methacrylate 30. In each case, the tetrafunctional initiator has produced faster rates of polymerization when compared to using the monofunctional initiator at an equivalent concentration.…”

“…Figure 5 shows typical results obtained for conversion versus time data (similar results have been obtained for other levels of temperature and initiator concentration). Details of the experimental procedure can be found elsewhere 28,29. The first observation to note is that when both initiators are employed at similar initiator concentrations, the tetrafunctional initiator reaches a specific conversion level before the polymerization with TBEC.…”

“…For example, it is known that in the polymerization of styrene, radicals predominately terminate by combination and there is no significant amount of transfer reactions at the temperatures being studied ( T < 120 °C). The next step was then to examine the use of JWEB50 in the polymerization of monomer whose termination is largely by radical disproportionation, namely methyl methacrylate (MMA) 29. Other systems that were examined include the copolymerization of MMA and α‐methylstyrene where depropagation reactions readily occur;30 the polymerization of butyl acrylate whose high rates of transfer to polymer produce branched chains and eventually gel material;31 and the polymerization of vinyl acetate where transfer to monomer and polymer reactions dominate 31.…”

“…The next step was then to examine the use of JWEB50 in the polymerization of monomer whose termination is largely by radical disproportionation, namely methyl methacrylate (MMA) 29. Other systems that were examined include the copolymerization of MMA and α‐methylstyrene where depropagation reactions readily occur;30 the polymerization of butyl acrylate whose high rates of transfer to polymer produce branched chains and eventually gel material;31 and the polymerization of vinyl acetate where transfer to monomer and polymer reactions dominate 31. As well, selective experiments were completed for the copolymerization of styrene and methyl methacrylate 30.…”

Role of choline formate ionic liquid in the polymerization of vinyl and methacrylic monomers

“…[1][2][3] Each of these methods is based on a different set of reaction conditions and solvents; nevertheless, in all cases, the addition of an initiator is necessary for polymerization. Free-radical polymerization is one of the most important ways of producing commercial polymers.…”