Molecular weight dependence of component dynamics in bidisperse melt rheology
Abstract
Simultaneous measurement of infrared dichroism and birefringence is used to study component relaxation in bimodal molecular weight distribution melts. Nearly monodisperse poly(ethylenepropylene) samples of molecular weights 53K, 125K, and 370K, all above the critical molecular weight for entanglement, were used. Results for the step-strain relaxation of each component and of the total sample are presented and discussed for binary blends of 10, 20, 30, 50, and 75% by volume of the higher molecular weight species for three seta of blends: 53K/125K, 53K/370K, and 125K/370K. For each sample, the relaxation dynamics of the blend and of each component depend upon the two polymer relaxation times and the blend composition. Effects of intermolecular orientational coupling interactions were observed, and a coupling strength of 0.45 was measured. The results of these experiments are compared to a reptation-based constraint release model, and a qualitative agreement is found.
Additional Information
© 1991 American Chemical Society. Received April 19, 1990; Revised Manuscript Received July 30, 1990. We are grateful to the National Science Foundation for support through the Presidential Young Investigator program for G. Fuller. This work was also supported by the Exxon Foundation and the Center for Materials Research at Stanford University. We thank Lewis Fetters for synthesizing the polymers used in this study.Additional details
- Eprint ID
- 88074
- DOI
- 10.1021/ma00003a019
- Resolver ID
- CaltechAUTHORS:20180720-134054459
- NSF
- Exxon Educational Foundation
- Stanford University
- Created
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2018-07-23Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field