Pulsed NMR study of elastomeric block copolymer under deformation
Article first published online: 9 MAR 2003
Copyright © 1989 John Wiley & Sons, Inc.
Journal of Applied Polymer Science
Volume 38, Issue 7, pages 1313–1334, 5 October 1989
How to Cite
Fukumori, K., Kurauchi, T. and Kamigaito, O. (1989), Pulsed NMR study of elastomeric block copolymer under deformation. J. Appl. Polym. Sci., 38: 1313–1334. doi: 10.1002/app.1989.070380711
- Issue published online: 9 MAR 2003
- Article first published online: 9 MAR 2003
- Manuscript Accepted: 25 AUG 1988
- Manuscript Received: 26 JUL 1988
Deformation behavior of an elastomeric styrene–butadiene–styrene block copolymer (SBS) is studied by pulsed NMR techniques, and is related to lifetime distributions and the change of the microstructure in the stress relaxation process. By the measurement of spin–spin relaxation time, it is found that polybutadiene (PB) chains in the vicinity of polystyrene (PS) domains come to be in more constrained conformations with stretching than those remote from the domains mainly through the intramolecular interactions, followed by the enlargement of the constrained regions, which reflects the roles of both crosslinks and filler particles in crosslinked rubbers. In the stress relaxation process, however, the mean lifetime for SBS at the critical strain is longer than that at lower strain in contrast with the results for the crosslinked rubbers. It is estimated that the differences between the failure behaviors of SBS and those of the conventional crosslinked rubbers may be mainly caused by the characteristic change of the microstructure (the disruption of the weak interconnections between the spherical PS domains with high energy dissipation) in SBS on deformation, associated with the limited extensibility of the PB chains between the adjacent PS domains. It becomes clear that the pulsed NMR method complements the mechanical measurements with a more precise information on the heterogeneity in the rubbery polymers under deformation.