Larger reversible deformations during the flow of mono- and poly-disperse elastomers

Abstract

The effects of the MWD on the highly elastic properties of elastomers were examined during flow under shear stress. The high elasticity modulus was found to be independent (in the case of polybutadiene as example) of the mol. wt., when the elastomers had a very narrow MWD. The MWD had a very strong effect on this modulus, especially when the fraction with a large mol. wt. was small. Formulae are suggested for describing the MWD effect on the high elasticity modulus. The experimental results are compared with those given in the literature as theoretical results. The effect of the rate of deformation on high elasticity was investigated and it is shown that a critical deformation, causing the transition from viscous flow to the highly elastic state, will make the high elasticity modulus correlate with that of elasticity within the range of the highly elastic state without the reversible deformations exceeding 200–300%.