Kinetics of interphase formation between incompatible polymers

In this work;, a theory for the kinetics of interphase formation between incompatible polymer pairs was developed. In this theoretical analysis, a local constitutive law for the diffusive flux is applied along the lines of the original Cahn-Hilliard equation. An approximate linear Cahn-Hilliard-type differential equation is derived which predicts interface adhesion energy G(a) following two power law growth before reaching equilibrium: G(a) proportional to t(1/2) when t < t(rep) (t(rep) is reptation rime): and G(a) proportional to t when t(rep) < t < t(eq). This is in qualitative agreement with recent experimental data on the kinetics of interphase formation between a monodisperse, incompatible polymer couple (polyisoprene/poly(methyl methacrylate)) as a function of annealing time. The data show two distinct features in the plot of G(a) versus t(1/2): at early times, a linearity is observed; at later times, there appears an abrupt upward turn followed by a downward curvature before reaching equilibrium.