ABSTRACT
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 ∝ t 1/2 when t < t rep (t rep is reptation time); and G a ∝ 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.
