Jump to main content
Jump to site search

Issue 13, 2019
Previous Article Next Article

Tuning cavitation and crazing in polymer nanocomposite glasses containing bimodal grafted nanoparticles at the nanoparticle/polymer interface

Author affiliations

Abstract

It is widely accepted that adding nanoparticles (NPs) into polymer matrices can dramatically alter the mechanical properties of the material, and that the properties at the NP/polymer interface play a vital role. By performing coarse-grained molecular dynamics simulations, we study the stress–strain behaviour of polymer/NP composites (PNCs) in a glassy state under a triaxial tensile deformation, in which the NPs are well dispersed in the system via bimodal grafting. A ‘HOMO’ system, in which the short grafted chains are chemically identical to the matrix polymer, and a ‘HETERO’ system, in which the short grafted chains interact weakly with the matrix, are investigated. Our simulations demonstrate that the HOMO system behaves very similarly to the pure polymer system, with quick cavitation and a drop in stress after the yielding point, corresponding to a craze deformation process. While in the HETERO system, weak interactions between the short grafts and the matrix polymer induce a low local modulus, therefore, rather homogeneous void formation and consequently a slower cavitation process are observed at the surface of the well dispersed NPs during the tensile deformation. As a result, the depletion effect at the NP surface eventually leads to NP re-assembly at large strains. Moreover, the HETERO system undergoes a shear-deformation-tended tensile process rather than the craze deformation found in the HOMO system. At the same time, the HETERO system is more ductile, with a much slower drop in stress after yielding than the HOMO system. In addition, the homogeneous generation of voids at small strain in the HETERO system can be utilized in the fabrication of polymer films with desirable separation abilities for gases or small molecules. We hope that these simulation results will be helpful for the property regulation of PNC materials containing polymer grafted NPs.

Graphical abstract: Tuning cavitation and crazing in polymer nanocomposite glasses containing bimodal grafted nanoparticles at the nanoparticle/polymer interface

Back to tab navigation

Article information


Submitted
12 Jan 2019
Accepted
11 Mar 2019
First published
12 Mar 2019

Phys. Chem. Chem. Phys., 2019,21, 7115-7126
Article type
Paper

Tuning cavitation and crazing in polymer nanocomposite glasses containing bimodal grafted nanoparticles at the nanoparticle/polymer interface

R. Shi, H. Qian and Z. Lu, Phys. Chem. Chem. Phys., 2019, 21, 7115
DOI: 10.1039/C9CP00208A

Social activity

Search articles by author

Spotlight

Advertisements