The Diffusion and Permeation of CFC-11,CFC-12,CFC-114,HCFC-22,and FC-14 through Polymer Films —The Relevance to Insulation Foams

Abstract

The diffusion coefficients and permeabilities of CCl₃F, CCl ₂F₂, C₂Cl₂F₄, CHClF ₂, and CF₄ through thin films of Elvax® 3137 ethylene-vinyl acetate copolymer, Surlyn® 1652 ionomer, Alathon® PE 5753 polyethylene, and Mylar® LBT polyester were determined in the temperature range 0 to 40°C in a typical per meation cell. The degree of crystallinity of each polymer as determined by X-ray scattering was used to aid the interpretation of results. Activation energies for diffu sion and permeation in these systems were calculated. The two most important fac tors in determining diffusivities and permeabilities in these systems are the molecular interaction between polymer and penetrant and the degree of crystallinity of the polymer. The molecular size of the diffusing molecules is a lesser factor in the systems studied.