Kinetics of thermally induced phase separation in a crystallizable polymer solution

Small angle light scattering, differential scanning calorimetry, and electron microscopy have been used to quantify the kinetics of liquid-liquid phase separation and crystallization during thermal quenching of a polyethylene copolymer in anisole solution. Measurements of the time dependence of the position of the light scattering maximum were made following temperature quenching to various regions of the phase diagram. For quenches to temperatures above the crystallization temperature, domain growth rates increase with increasing quench depth and decreasing overall polymer concentration. Light scattering and microscopy show that solutions quenched to regions below the crystallization temperature show a brief coarsening period before structure growth is arrested by crystallization. Simultaneous measurement of the transient solution temperature indicates that cessation of domain growth occurs when the solution temperature crosses the crystallization line.