KINETICS OF THERMALLY-INDUCED PHASE-SEPARATION IN A CRYSTALLIZABLE POLYMER-SOLUTION

Small angle light scattering, differential scanning calorimetry, and e lectron microscopy have been used to quantify the kinetics of liquid-l iquid phase separation and crystallization during thermal quenching of a polyethylene copolymer in anisole solution. Measurements of the tim e dependence of the position of the light scattering maximum were made following temperature quenching to various regions of the phase diagr am. For quenches to temperatures above the crystallization temperature , domain growth rates increase with increasing quench depth and decrea sing overall polymer concentration. Light scattering and microscopy sh ow that solutions quenched to regions below the crystallization temper ature show a brief coarsening period before structure growth is arrest ed by crystallization. Simultaneous measurement of the transient solut ion temperature indicates that cessation of domain growth occurs when the solution temperature crosses the crystallization line.