Structure-property relationships in polycaprolactone-polyurethanes
Article first published online: 11 MAR 2003
Copyright © 1983 John Wiley & Sons, Inc.
Journal of Polymer Science: Polymer Physics Edition
Volume 21, Issue 1, pages 65–95, January 1983
How to Cite
Van Bogart, J. W. C., Gibson, P. E. and Cooper, S. L. (1983), Structure-property relationships in polycaprolactone-polyurethanes. J. Polym. Sci. Polym. Phys. Ed., 21: 65–95. doi: 10.1002/pol.1983.180210106
- Issue published online: 11 MAR 2003
- Article first published online: 11 MAR 2003
- Manuscript Accepted: 13 JUL 1982
- Manuscript Received: 27 JUL 1981
The structure-property relationships of polycaprolactone-based segmented polyurethanes were studied using differential scanning calorimetry (DSC), small-angle x-ray scattering (SAXS), wide-angle x-ray diffraction (WAXD), dynamic mechanical, and stress-strain testing. The materials studied varied in hard-segment type [4,4′-diphenylmethane diisocyanate/butanediol (MDI/BD) or 4,4′-dicyclohexyl methane diisocyanate/butanediol (H12MDI/BD)], soft-segment molecular weight (830 or 2000 MW polycaprolactone), hard-segment content (23–77% by weight), and thermal history. The materials with aromatic (MDI/BD) hard segments had semicrystalline hard-segment domains, while the materials with aliphatic (H12MDI/BD) hard segment had mostly amorphous domains. Materials with the shorter polycaprolactone soft segment (830 MW) exhibited thermal and mechanical behavior which indicated a considerable degree of hard- and soft-segment compatibility. The materials which contained a 2000-MW polycaprolactone soft segment exhibited better-defined microphase separation. SAXS was used to characterize the microphase structure of each system. The effects of hard-segment content and soft-segment molecular weight were similar for the aromatic (MDI) and aliphatic (H12MDI) hard-segment-based block copolymers. Changing the hard segment from aromatic to aliphatic gave materials with larger interfacial area and slightly higher tensile strength. A range of morphologies between isolated hard domains in a rubbery matrix and isolated rubbery domains in a hard matrix was observed.