Structure development in multi-block copolymerisation: comparison of experiments with cell dynamics simulations

A cell dynamics simulation of phase separation in block copolymers is compa red with experimental observations for two related systems, polyurethane (p oly(ether-urea)) foam and poly(ether-isocyanurate). Time resolved SAXS meas urements on both systems suggest a spinodal-like mechanism with kinetics fo llowing a time-dependent Ginzburg-Landau (TDGL) model. TEM micrographs from a range of sources show reactively processed multi-block copolymers to hav e a bicontinuous morphology, which is discussed as a non-equilibrium relic of the phase separation process. A TGDL based cell-dynamics model gives pre dictions of the morphology, which can be compared to TEM images and SAXS pa tterns, The model does not contain any reactive aspects but captures the mo rphology of the systems which both showed pinning of the micro-structure at early stages of microphase separation in contrast to the equilibrium struc tures formed by block copolymers. (C) 1999 Elsevier Science Ltd, All rights reserved.