The roles of blending and of molecular weight distribution on craze initiation
Craze initiation stress was measured in three-point bending isochronal creep tests on a series of entangled bimodal blends of polystyrenes of narrow dispersity, on three polystyrenes of broad dispersity, and on four blends of polystyrenes of broad dispersity. Crazing stress was found to increase rap...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Published: |
American Chemical Society
2017
|
| Subjects: | |
| Online Access: | https://eprints.nottingham.ac.uk/48209/ |
| _version_ | 1848797714735693824 |
|---|---|
| author | Sánchez-Valencia, Andrea Smerdova, Olga Hutchings, Lian R. De Focatiis, Davide S.A. |
| author_facet | Sánchez-Valencia, Andrea Smerdova, Olga Hutchings, Lian R. De Focatiis, Davide S.A. |
| author_sort | Sánchez-Valencia, Andrea |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | Craze initiation stress was measured in three-point bending isochronal creep tests on a series of entangled bimodal blends of polystyrenes of narrow dispersity, on three polystyrenes of broad dispersity, and on four blends of polystyrenes of broad dispersity. Crazing stress was found to increase rapidly with small additions of the higher molar mass component, quickly reaching a plateau. A simple model based on the weighted addition of the crazing stress contributions of the individual weight fractions obtained from an established piecewise linear crazing law was able to predict the crazing stress accurately in the bimodal blends using a power law exponent of 2.59 (90% CI [1.75–17.34]). In broad dispersity systems, in particular where short unentangled chains dilute the polymer, it was found necessary to modify the model using dynamic tube dilution theory. Dilution leads to a change in the entanglement length and hence in the molar mass at which transitions to disentanglement and chain scission crazing occur. With the improved model, crazing stress could be predicted even for the broad dispersity polymers with wide and bimodal distributions. This represents an opportunity for the molecular design of polymers by blending to achieve improved resistance to craze initiation. |
| first_indexed | 2025-11-14T20:08:16Z |
| format | Article |
| id | nottingham-48209 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T20:08:16Z |
| publishDate | 2017 |
| publisher | American Chemical Society |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-482092020-05-04T19:18:58Z https://eprints.nottingham.ac.uk/48209/ The roles of blending and of molecular weight distribution on craze initiation Sánchez-Valencia, Andrea Smerdova, Olga Hutchings, Lian R. De Focatiis, Davide S.A. Craze initiation stress was measured in three-point bending isochronal creep tests on a series of entangled bimodal blends of polystyrenes of narrow dispersity, on three polystyrenes of broad dispersity, and on four blends of polystyrenes of broad dispersity. Crazing stress was found to increase rapidly with small additions of the higher molar mass component, quickly reaching a plateau. A simple model based on the weighted addition of the crazing stress contributions of the individual weight fractions obtained from an established piecewise linear crazing law was able to predict the crazing stress accurately in the bimodal blends using a power law exponent of 2.59 (90% CI [1.75–17.34]). In broad dispersity systems, in particular where short unentangled chains dilute the polymer, it was found necessary to modify the model using dynamic tube dilution theory. Dilution leads to a change in the entanglement length and hence in the molar mass at which transitions to disentanglement and chain scission crazing occur. With the improved model, crazing stress could be predicted even for the broad dispersity polymers with wide and bimodal distributions. This represents an opportunity for the molecular design of polymers by blending to achieve improved resistance to craze initiation. American Chemical Society 2017-11-20 Article PeerReviewed Sánchez-Valencia, Andrea, Smerdova, Olga, Hutchings, Lian R. and De Focatiis, Davide S.A. (2017) The roles of blending and of molecular weight distribution on craze initiation. Macromolecules, 50 (23). pp. 9507-9514. ISSN 1520-5835 Crazing molar mass dispersity polystyrene molecular weight distribution bimodal blends http://pubs.acs.org/doi/abs/10.1021/acs.macromol.7b01289 doi:10.1021/acs.macromol.7b01289 doi:10.1021/acs.macromol.7b01289 |
| spellingShingle | Crazing molar mass dispersity polystyrene molecular weight distribution bimodal blends Sánchez-Valencia, Andrea Smerdova, Olga Hutchings, Lian R. De Focatiis, Davide S.A. The roles of blending and of molecular weight distribution on craze initiation |
| title | The roles of blending and of molecular weight distribution on craze initiation |
| title_full | The roles of blending and of molecular weight distribution on craze initiation |
| title_fullStr | The roles of blending and of molecular weight distribution on craze initiation |
| title_full_unstemmed | The roles of blending and of molecular weight distribution on craze initiation |
| title_short | The roles of blending and of molecular weight distribution on craze initiation |
| title_sort | roles of blending and of molecular weight distribution on craze initiation |
| topic | Crazing molar mass dispersity polystyrene molecular weight distribution bimodal blends |
| url | https://eprints.nottingham.ac.uk/48209/ https://eprints.nottingham.ac.uk/48209/ https://eprints.nottingham.ac.uk/48209/ |