Low-field NMR studies of polymer crystallization kinetics:: Changes in the melt dynamics

The free induction decay in H-1 NMR experiments carried out for crystallizing polymers can be directly decomposed in contributions from crystals, melt-like regions and amorphous regions with a reduced mobility. Here, the results of time-dependent experiments conducted with the aid of a cost-efficient low-field NMR instrument are presented, obtained for sPP, P epsilon CL and P(EcO). Crystallization isotherms are compared with those, obtained by X-ray scattering and dilatometry. There are some minor systematic deviations which can be explained and accounted for. For all systems, a large fraction of amorphous chain parts in regions with a reduced mobility is found. (c) 2006 Elsevier Ltd. All rights reserved.