Photolytic decomposition of polymethacrylates. Part 2.—Poly(methyl methacrylate); quantum yields and molecular weight changes

Abstract

The quantum yields measured for the scission of main chain bonds and for the production of monomer during photochemical decomposition of poly(methyl methacrylate) at temperatures above 433 K indicate that the mechanism of the reaction is random scission of polymer backbone bonds which takes place following some primary absorption process, with complete unzipping of the macromolecules to produce monomer. The unusual dependence of the rate of the reaction on the initial weight of the sample is considered to be related to the transfer of energy, after the primary absorption, leading to main-chain bond scission.