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Large deformations in oriented polymer glasses: experimental study and a new glass-melt constitutive model

De Focatiis, Davide S.A.; Embery, John; Buckley, C.Paul

Authors

Davide S.A. De Focatiis

John Embery

C.Paul Buckley



Abstract

An experimental study was made of the effects of prior molecular orientation on large tensile deformations of polystyrene in the glassy state. A new hybrid glass-melt constitutive model is proposed for describing and understanding the results, achieved by parallel coupling of the ROLIEPOLY molecularly-based melt model with a model previously proposed for polymer glasses. Monodisperse and polydisperse grades of polystyrene are considered. Comparisons between experimental results and simulations illustrate that the model captures characteristic features of both the melt and glassy states. Polystyrene was stretched in the melt state and quenched to below Tg, and then tensile tested parallel to the orientation direction near the glass transition. The degree of strain-hardening was observed to increase with increasing prior stretch of molecules within their entanglement tubes, as predicted by the constitutive model. This was explored for varying temperature of stretching, degree of stretching, and dwell time before quenching. The model in its current form, however, lacks awareness of processes of subentanglement chain orientation. Therefore, it under-predicts the orientation-direction strain hardening and yield stress increase, when stretching occurs at the lowest temperatures and shortest times, where it is dominated by subentanglement orientation.

Journal Article Type Article
Publication Date Jul 1, 2010
Journal Journal of Polymer Science Part B: Polymer Physics
Print ISSN 0887-6266
Electronic ISSN 0887-6266
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 48
Issue 13
APA6 Citation De Focatiis, D. S., Embery, J., & Buckley, C. (2010). Large deformations in oriented polymer glasses: experimental study and a new glass-melt constitutive model. Journal of Polymer Science Part B: Polymer Physics, 48(13), doi:10.1002/polb.22028
DOI https://doi.org/10.1002/polb.22028
Keywords constitutive model;glass transition ; orientation ; polystyrene ; rheology ; ROLIEPOLY ; simulations
Publisher URL http://onlinelibrary.wiley.com/doi/10.1002/polb.22028/abstract
Copyright Statement Copyright information regarding this work can be found at the following address: http://creativecommons.org/licenses/by/4.0

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Copyright Statement
Copyright information regarding this work can be found at the following address: http://creativecommons.org/licenses/by/4.0





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