A coalescence mechanism for the coarsening behavior of polymer blends during a quiescent annealing process. II. Polydispersed particle system

A coalescence mechanism for the coarsening behavior of polymer blends durin g a quiescent annealing process is proposed, in which the effect of differe nt particle sizes is taken into consideration. All existing forces, such as thermal agitation, van der Waals attraction, interfacial tension, and visc ous resistance, control the coarsening process. The evolution of the partic le size and its distribution are modeled with a particle population balance equation. The experimental investigation has been made with the transmissi on electron microscopy observation of a polystyrene/poly( methyl methacryla te) blend during the annealing process. The model predictions are in good a greement with our experiment and other authors' work. The relative effects of system parameters such as volume fraction, interfacial tension, and visc osity on the particle size distribution are also discussed. (C) 2000 John W iley & Sons, Inc.