CRYSTAL NUCLEATION IN FLOWING POLYMER MELTS.

Crystal nucleation in undercooled, flowing polymer melts is accelerated by amounts that can be predicted quantitatively by common expressions for nucleation kinetics. The adaptation of these relationships culminates in the simple addition of the free energy difference between melt and solid which could form from it to a free energy quantity based solely on the reduction in configurational entropy that flow causes the chains to experience. Precise agreement between this prediction and experimental results is possible when one uses a statistical mechanical approach, based on a Lodge model, to calculate this reduction in configurational entropy. Experiments have been performed using a novel elogational viscometer on crystal nucleation kinetics of hydrogenated polybutadienes.