DSC studies of thermally induced phase separation of hydrogen bonded polymer blends

The thermally induced phase separation behavior of hydrogen bonded polymer blends, poly(n-hexyl methacrylate) (PHMA) blended with poly(styrene-co-viny l phenol) (STVPh) random copolymers having various vinyl phenol contents, w as studied by temperature modulated differential scanning calorimetry (TMDS C). The enthalpy of phase separation was determined to be about 0.5 cal g(- 1) for one of the blends. A phase diagram was constructed from the TMDSC da ta for one of the blends. The kinetics of phase separation was studied by d etermining the phase compositions from the glass transition temperatures of quenched samples after phase separation. Subsequently, the phase separated samples were annealed at temperatures below the phase boundary to observe the return to the homogeneous state.