ISSN:
0887-6266
Keywords:
nuclear magnetic resonance (NMR) of MDI-based polyurethanes
;
polyurethanes, MDI-based, solid-state NMR of
;
chain motion and microphases in segmented polyurethanes
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
13C solid-state nuclear magnetic resonance (NMR) experiments on linear polyurethanes and poly(ether-urethane) block copolymers demonstrate that 13C spin-lattice relaxation experiments in the laboratory [T1(C)] and rotating [T1p(C)] frames provide the most information about domain morphology in these microphase-separated polymer systems. T1(H) TCH, and T1p(H) data are less useful in a 4,4′-methylene bis(p-phenyl isocyanate)-1,4-butanediol (MDI/BD) hard-segment material, the MDI bridging methylene and the MDI urethane carbonyl T1(C and T1p(C) times fall in characteristic ranges for crystalline, amorphous, interfacial, and dissolved species. BD methylene carbons have short T1p(C) for crystalline and long T1p(C) for amorphous hard-segment aggregates. The distinct T1p(C) and T1(C) fractins observed are attributed to the presence of several crystalline polymorphs. Both T1(C) results and DSC endotherms indicate that the crystalline polymorphs present in the poly(ether-urethane) are less ordered than the types seen in the pure hard-segment material. © 1993 John Wiley & Sons, Inc.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/polb.1993.090310911
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