Publication detail

Effect of temperature, strain rate and particle size on the yield stresses and post-yield strain softening of PMMA and its composites

JANČÁŘ, J. HOY, R. JANČÁŘOVÁ, E. ŽÍDEK, J.

Original Title

Type

journal article in Web of Science

Language

English

Original Abstract

The extent of strain softening controls strain localization and governs the character of the post-yield response of polymer glasses. In order to understand how solid particles affect strain softening in a common glassy polymer, we investigate the composition dependence of the upper (sy), lower (sfl), and rejuvenated (syr) yield stresses of neat PMMA as well as glass microparticle (MP) and silica nanoparticle (NP) filled PMMA composites. All yield stresses increase with the filler volume fraction vf, as expected; the extent of this enhancement increases with T, and is uniformly larger for NP- than for MP-filled systems. This trend cannot be interpreted using simple volume-replacement models; we interpret their breakdown as arising from NP-imposed alteration of segment-scale packing and dynamics at the filler-matrix interface. Furthermore, they vary qualitatively differently with temperature and strain rate, leading to disparate responses of two measures of strain softening (Dsfl 1/4 sy sfl and Ds yr 1/4 sy syr). We analyze these results in terms of recent microscopic and constitutive models. The strain rate dependence of Dsfl agrees well with predictions of the Chen-Schweizer PNLE model, while poorer agreement is found for temperature dependence. Finally, we extend the recently developed three-region picture of strain softening (van Breemen LCA, Engels TAP, Klompen ETJ, Senden DJA, Govaert LE, J Polym Sci Polym Phys 2012, 50, 1757) to composite systems. Our results should lead to an improved understanding of the factors controlling plastic deformation of polymer composites.

Keywords

Yielding, Particle size, PMMA

Authors

JANČÁŘ, J.; HOY, R.; JANČÁŘOVÁ, E.; ŽÍDEK, J.

RIV year

2015

Released

20. 4. 2015

ISBN

0032-3861

Periodical

Polymer

Year of study

Number

State

United Kingdom of Great Britain and Northern Ireland

Pages from

196

Pages to

207

Pages count

BibTex

@article{BUT113758,
  author="Josef {Jančář} and Robert S. {Hoy} and Ema {Kopuletá} and Jan {Žídek}",
  title="Effect of temperature, strain rate and particle size on the yield stresses and post-yield strain softening of PMMA and its composites",
  journal="Polymer",
  year="2015",
  volume="63",
  number="1",
  pages="196--207",
  doi="10.1016/j.polymer.2015.03.001",
  issn="0032-3861"
}