Polymerization of diethylene glycol bis(allyl carbonate) by means of di‐sec‐butyl peroxydicarbonate

Abstract

AbstractThe initial stages of the free radical polymerization of diethylene glycol bis(allyl carbonate) at temperatures of 35–65°C have been studied. The polymer is unsaturated and cyclization to give a 16‐membered ring occurs only to a small extent. The kinetic order with respect to the initiator, di‐sec‐butyl peroxydicarbonate, has an average value of 0.79; the order increases slightly with peroxydicarbonate concentration over the range 0.018–0.22M. The molecular weight of the polymer isolated after 3% polymerization is close to 19,000. It shows no significant dependence on initiator concentration or on temperature. The dominant feature of the bulk polymerization, as in free radical polymerization of the other allyl and diallyl monomers, is degradative chain transfer in which the growing polymer radical abstracts a hydrogen atom from a monomer unit to give a relatively unreactive allylic radical. The dependence of rate on initiator concentration is rationalized if some of these allylic radicals are able to reinitiate polymerization. The transfer constant to monomer is 0.014 at 50°C, assuming that the main termination step involves mutual termination of allylic radicals. Carbon tetrachloride is an active transfer agent with a transfer constant of 0.20 ± 0.04 at 50°C. Toluene, which is less active, has a transfer constant of 0.0064 at 50°C and also retards the polymerization. Some kinetic studies have been made with other initiators, including di‐2‐methyl‐pentanoyl peroxide which initiates polymerization at temperatures as low as 13°C.