Mechanism of Cyclopolymerization of Vinyl Acrylate, Methacrylate, and α-Chloroacrylate

Abstract

Polymers of vinyl acrylate, methacrylate, and a-chloroacrylate were prepared by radical polymerization at 60°C at various monomer concentrations in benzene. The residual double bond in the polymers was determined to be mainly a vinyl group by infrared spectroscopy and ICl titrimetry. The decrease in the residual double bond with decreasing monomer concentration can be explained in terms of an intramolecular chain monocyclization-bicyclization mechanism. The proposed monocyclization was carried out between the polymer radical and vinyl group of a penultimate monomer unit. Bicyclization was carried out between a monocyclized radical and vinyl group of the polymer end. The ratios of monocyclization rate constant over intermolecular propagation rate constant were evaluated to be 20 for vinyl acrylate, 0.22 for vinyl methacrylate and 0.60 mol dm-3 for vinyla-chloroacrylate, respectively. The ratios of bicyclization rate constant over intermolecular propagation rate constant were evaluated to be 0.1 mol dm-3 for all the monomers.

Thiol−Ene Photopolymerization Kinetics of Vinyl Acrylate/Multifunctional Thiol Mixtures

“…Within 7 s, acrylate group conversion reaches about 85% while much less than 10% of the vinyl groups are consumed. This result is consistent with previous reports by Kudyakov and Fukuda et al [15][16][17] We next note that the conversion rate of the acrylate group of vinyl acrylate is significantly faster than for ethyl acrylate (Figure 2b) using 365 nm light (vinyl acrylate does not absorb at this wavelength) with an added photoinitiator. Within 6 s, almost 80% of the acrylate double bonds are converted to polymer while only about 15% of ethyl acrylate polymerizes under the same photolysis conditions and irradiation time.…”

Cyclopolymerization of Isopropenyl Acrylate and Methacrylate

“…When intermolecular propaga-634 When intramolecular cyclization takes place between a growing polymer radical and the pendent isopropenyl group of a penultimate monomer unit and then that between a monocyclized radical and the isopropenyl group of a terminal monomer unit, eq 2 is introduced by the procedure of a former paper. 7 …”

“…Figure 3 sion, the cyclopolymerization of IP A and IPMA proceeds through the monocyclization-bicyclization mechanism proposed for those of VA, VMA, and VCA in the previous paper. 7 Table III summarizes the parameters of the cyclopolymerization. The most interesting feature is high reactivity of vinyl and isopropenyl groups of a penultimate monomer unit toward a growing polymer radical of VA and IPA.…”

“…7 The poly-(IPA) prepared at l.Omol dm-3 of monomer concentration will consist of 73.7% of the monocyclic unit and 9.6% of the bicyclic unit, while the poly(IPMA) will consist of 19.5% ofthe monocyclic unit and 1.1% of the bicyclic unit.…”

“…6 • 7 The mechanism of cyclopolymerization of VA, VMA, and VCA has been studied. 7 The suggested propagation reactions are intermolecular addition of a polymer radical to the aery! or a-substituted aery!…”