Molecular motion in solid amorphous polymers. The dielectric relaxation of a poly-nonyl methacrylate and poly-n-lauryl methacrylate as a function of frequency, temperature and applied pressure

Abstract

The dielectric relaxation of a polynonyl methacrylate (PNMA) and poly-n-lauryl methacrylate (PLMA) have been studied over a range of frequency, temperature and of applied hydrostatic pressure. Results for PNMA are consistent with α, β and (αβ) relaxations occurring in the polymer. For PLMA, the (αβ) relaxation decreases in magnitude with increasing pressure or decreasing temperature, with no apparent evidence for α and β relaxations. Activation energies are compared with those obtained for other amorphous polymers, and it is suggested that the (αβ) process in the higher methacrylate polymers has a slighly different mechanism from that observed in the lower alkyl methacrylate polymers.