POLYAMIDE POLYETHER BLOCK-COPOLYMERS SWOLLEN BY WATER .2. DEUTERIUM NMR-STUDIES

The mobility and orientation of D2O molecules in oriented block copoly mers of polyamide-polyether is studied by quadrupolar NMR. The mobilit y deduced from the line width follows the WLF equation and is independ ent of the draw ratio and the nature of the hard segment PA. This demo nstrates that water in these swollen thermoplastic elastomers is local ized mainly in the rubbery phase of polyether. The variation of the sp litting Delta nu of the NMR doublet with the macroscopic deformation l ambda and with the concentration shows that the deformation is not aff ine. The local deformation lambda of the chain in the rubbery phase c an be estimated by annealing the dry material just above the melting p oint of the PA sequences. The splitting is found to be a linear functi on of(lambda)2 - 1/lambda*, as expected by the theory of elasticity i f one assumes that the mean orientation of the O-D segments of water i n strained chain materials is proportional to the mean orientation of the chains, as has been verified by Sotta in PDMS rubber. Finally, thi s technique shows that the process of deformation of the polyether cha in in the soft phase of these materials, drawn at 20 degrees and 80 de grees C, is essentially the same.