Kinetics of Microphase Separation in Crosslinked Polymer Blend (abstract)

The solvent effect on the early kinetics of the microphase separation (MPS) in binary crosslinked polymer was studied. In the presence of a good solvent, calculations were done using first the random phase approximation method and second an extended blob model, where a crosslinked chain is viewed as a sequence having blobs as new units. Kinetics were studied through the variation of the relaxation rate, τq, upon the wave number, q, in the region around the spinodal temperature. When the temperature is changed from an initial value, Ti, toward the final value, Tf, very close to the critical point, the only motion allowed to the crosslinked chains is of Rouse type because of the presence of the crosslinks. The swelling effect on the MPS leads to a multiplicative renormalization of critical parameters of the molten state by factors as power of the overall monomer volume fraction, φ. The characteristic frequency, Ω(q), inverse of τq, scales as Ω(q) ≅ q6e3, where e stands for the traditional screening length. ...