Anisotropic and heterogeneous dynamics in stretched elastomer nanocomposites.

摘要: We use X-ray photon correlation spectroscopy (XPCS) to investigate the dynamics of a stretched elastomer by means probe particles. The particles dispersed in were carbon black or silica aggregates classically used for reinforcement but their volume fraction is very low (ϕ < 10−2). show that slower direction tensile strain than perpendicular one. For hydroxylated which poorly wetted elastomer, there no anisotropy. Two-time functions confirm anisotropic and suggest dynamical heterogeneity already expected from q−1 behavior relaxation times. height χ* peak susceptibility, determined normalized variance instantaneous function, larger parallel It also appears its q dependence changes with morphology particle. Therefore, heterogeneous dynamic probed not related only strained matrix. In fact, it results modification polymer chains near surface within aggregate porosity (bound polymer). concluded XPCS powerful method investigating dynamics, at given strain, bound polymer–particle units are responsible, large fractions, reinforcement.