Physical ageing in poly(4‐hydroxy styrene)/poly(vinyl methyl ether) blends

Abstract

Abstract The influence of blend composition on enthalpy‐relaxation behaviour was assessed for miscible blends of poly(4‐hydroxy styrene)/poly(vinyl methyl ether) (PHS/PVME). Values of enthalpy lost (Δ H ( T a , t a )) were calculated from experimental data plotted against log ( t a ) and modelled using the Cowie–Ferguson (CF) expression. This gives a set of values for three adjustable parameters, Δ H ∞ ( T a ), log ( t c ) and β. Positron annihilation lifetime spectroscopy (PALS) measurements indicated that all of the blends, except the blend with 59 mol% of the PHS component, have greater free volume than pure PHS. Furthermore, infrared spectroscopy was useful for assessing the hydrogen‐bonding interactions in the blends. The ageing results are discussed with reference to the strength of the interactions and free volumes, and are compared with related systems. Copyright © 2005 Society of Chemical Industry