Elastic properties of polvinyl chloride gels

Abstract

Abstract Young's moduli are measured by a simple compression method on plasticized polyvinyl chloride (Vinylite VYNW) compounds containing from 5 to 100% polymer covering a range of approximately seven orders of magnitude in modulus. By comparing values obtained at different temperatures, it is shown that the 60‐second modulus in the range of 25°C. is largely due to entropy changes occurring during deformation of compounds containing less than about 50% polymer, but upon internal energy changes in compounds containing higher concentrations of resin. A semiquantitative description of the three‐dimensional polyvinyl chloride network existing in the soft‐gel region is arrived at from the kinetic theory of elasticity, and a network structure is suggested for the region of high resin content. A method for comparing relative solvent power of various plasticizers is suggested based on moduli determined in the soft‐gel region. Effects of polymer composition on the network structure are also discussed.