Composition dependence of polymerization-induced phase separation of 2-chlorostyrene/polystyrene mixtures

Dynamics of phase separation induced by polymerization of 2-chlorostyrene in the presence of polystyrene was studied by an scanning electron microscope and a time-resolved light scattering instrument with varying initial monomer composition θ in the range from 0.4 to 0.6. Phase-separation rate increased with increasing θ or temperature. Phase being rich in poly(2-chlorostyrene) formed droplets initially and these droplets coagulated to form continuous domains at low temperatures. A maximum was found in the initial-composition dependence of the time when morphological change from droplets to continuous domains occurred. Qualitative discussion was made for the effects of initial composition change on morphological change of poly(2-chlorostyrene)-rich phase.