Title :
Polyurethane cross-linking by chromium(III) compounds
Author :
Gahde, J. ; Goering, H. ; Gehrke, R. ; Hiller, W.
Author_Institution :
KAI eV, Berlin, Germany
fDate :
7/1/1993 12:00:00 AM
Abstract :
Dynamic mechanical measurements were carried out to characterize the influence of chromium dioxide and chromium(III) chloride magnetic pigments on the structure of linear segmented polyurethanes. Both the chromium dioxide and the chromium(III) chloride act as curing agent. The network formation depends on the structure of the polyurethanes and the concentration of the chromium compounds. Nuclear magnetic resonance (NMR) measurements confirmed that chromium(III) chloride shows a strong interaction with the urethane group (NH and CO) by complex formation and a moderate interaction with the ester group (CO). The results are used to discuss a model structure for the modified polyurethanes
Keywords :
chromium compounds; magnetic properties of fine particles; magnetic recording; magnetic thin films; polymer films; Cr-Cl; CrO2; NMR; curing agent; ester group; linear segmented polyurethanes; magnetic pigments; magnetic tapes; particulate media; structure; Chromium; Curing; Disk recording; Magnetic films; Magnetic recording; Mechanical variables measurement; Nuclear magnetic resonance; Pigments; Polymers; Temperature;
Journal_Title :
Magnetics, IEEE Transactions on
