Review of Measurement and Modelling of Permeation and Diffusion in Polymers

Diffusion and permeation in polymeric materials is of fundamental importance in many applications and is the subject of considerable scientific interest. Measurement methods for determining permeation through polymer sheets and within polymeric materials have been reviewed. An overview of the generic mechanisms involved reveals dependence of these properties on a wide range of factors, some relating to the materials others to the exposure environments. There can often be an interrelationship between factors, for example the combination of stress and chemical exposure is often a critical degradation mechanism in the service performance of polymeric structures. Dispersed phases and interfaces play important roles in the mass transport process but the mechanisms are not well understood, limiting predictive capabilities. Modelling is used to supplement experimental measurements, improving understanding and enabling extrapolation of behaviour over timescales and in large components that are not experimentally convenient. Performance 2004-2007 Project deliverable F07/d1 NPL Report DEPC MPR 012  Crown copyright 2005 Reproduced with the permission of the Controller of HMSO and Queen’s Printer for Scotland