Macromolecular Research, Vol.30, No.4, 271-278, April, 2022
Application of Three-Dimensional Solubility Parameter in Diffusion Behavior of Rubber-Solvent System and Its Predictive Power in Calculating the Key Parameters
Three different rubbers, hydrogenated nitrile butadiene rubber (HNBR), ethylene vinyl acetate copolymer (EVM) and ethylene propylene diene rubber (EPDM), and two blends, HNBR/EVM and HNBR/EPDM were compounded both with and without fillers, and were vulcanized with the same peroxide curing system. Peppas- Sahlin model was used to explain the diffusion mechanism of solvents in rubber vulcanizates. Transport parameters including diffusion coefficient, sorption coefficient and permeation coefficient were calculated and correlated with Flory-Huggins interaction parameters (χ). The Peppas-Sahlin model dealing with diffusion behaviors of solvents shows high degree of fitting for both unfilled and filled rubber-solvent systems. With the addition of carbon black, the diffusion coefficient increases while the sorption and permeation coefficients decrease. The sorption coefficient increases linearly with the permeation coefficient. New Flory-Huggins interaction parameter (χN) calculated by threedimensional solubility parameters shows better predictive power in diffusion behaviors than the traditional one (χT). By mathematical fitting, a linear relationship can be obtained between the maximum swelling ratio and χN, while an exponential relationship is gained for the permeation coefficient. The discovery of this rule connects three-dimensional solubility parameters with the swelling of polymer in solvent, which provides experimental basis for the further study of the medium resistance of polymer.
Keywords:three-dimensional solubility parameter;flory-huggins interaction parameter;diffusion behavior;prediction model