Dependence of the glass transition temperature of poly(methyl methacrylate) on tacticity and molecular weight

Abstract

Abstract The preparation of five samples of poly(methyl methacrylate) covering a wide range of tacticity and their electron irradiation to produce series of varying molecular weight are described. The glass transition temperature T g of each polymer was determined by DTA techniques. Plots of T g and the reciprocal of the molecular weight are well fitted in every case by a straight line. The data are also fitted to the Gibbs‐DiMarzio theory and the values of the energy and free‐volume parameters obtained are discussed. A method of estimating T g of pure syndiotactic poly(methyl methacrylate) by extrapolation is presented, the value obtained being 160°C.