Effect of side chain concentration on the intensity and temperature of the low-temperature dispersion of polymethacrylate copolymers

Effect of the concentration of the side chains HO─CH2─CH2─ and CH3─(CH2)3─ on the low-temperature dispersion was investigated for the copolymers of β-hydroxyethyl methacrylate with methyl meth-acrylate and of n-butyl methacrylate with methyl methacrylate. The decrease in the number of side chains in a unit volume manifests itself in both series of copolymers by a linear decrease in the intensity of the relaxation process and in the temperature at which the relaxation motion sets in. The shape of the corresponding loss maximum remains virtually unchanged. An attempt was made to explain the temperature shifts of the low-temperature dispersion in terms of changes in the free volume accessible to the side chains.