Yielding Behavior of Rubber-Particles Melts of Poly(n-butylacrylate)

Abstract

The yielding behavior of the melts of poly(n-butyl)acrylate rubber-particles with various cross-link densities in feed (c_x) is investigated by the creep and recovery tests, and the large amplitude oscillation (LAOS) measurements. The measurements reveal the presence of a yield stress for the onset of plastic flow. The equilibrium shear modulus (G₀), which is measured at the small stresses below the yield stress, increases with an increase in c_x as G₀ ~ c_x^0.5. The yield strain (γ_c ≈ 2 × 10^-2) is almost independent of c_x and temperature. The c_x-insensitive γ_c is qualitatively similar to the earlier results for the highly dense suspensions of micro-hydrogels.