Stress relaxation in stretched networks immersed in solvent

Abstract

AbstractStress relaxation in swollen polybutadiene networks is studied. The networks, which are immersed in solvent at equilibrium, are uniaxially stretched suddenly and the relaxation of the force required to keep them at constant length is monitored. The observed relaxation is predominantly due to the diffusion of solvent into the stretched networks. Measurements are made at different extensions and temperatures. The degree of swelling of the networks is calculated as a function of the observed force by adopting the phantom network model of rubber elasticity. The relationship between the diffusion of solvent into the networks and stress relaxation is given. The variation of the degree of swelling with time is used to calculate the coefficients of diffusion for n‐hexane and dodecane in polybutadiene.