A DIRECT COMPARISON OF SPINODAL DECOMPOSITION ANALYSIS BY TIME AND Q-RESOLVED LIGHT-SCATTERING AND NMR

Time and q resolved light scattering and nuclear magnetic resonance sp in-lattice relaxation time have been performed on polystyrene/poly(vin yl methyl ether) blends during the early stage of the spinodal decompo sition. The two techniques are used to determine the apparent diffusio n coefficient at two different temperatures. A satisfying agreement is found between the results of T-1 n.m.r. measurements and those from l ight scattering. Otherwise, it has been shown that n.m.r. spin-lattice relaxation measurements, during the decomposition time, permits discr imination between spinodal decomposition and nucleation and growth. T- 1 rho experiments indicate that the homogeneous phase as well as the p hase-separated quenched blend contain short scale inhomogeneities but it is not clear whether they compete with the larger scale spinodal de composition process. (C) 1997 Elsevier Science Ltd.