Nonlinear “oddities” at the percolation of 3D hierarchical graphene polymer nanocomposites
Artikel i vetenskaplig tidskrift, 2020

The nonlinear rheology of a novel 3D hierarchical graphene polymer nanocomposites was investigated in this study. Based on an isotactic polypropylene, the nanocomposites were prepared using simple melt mixing, which is an industrially relevant and scalable technique. The novel nanocomposites stand out as having an electrical percolation threshold (≈0.94 wt%) comparable to solution mixing graphene-based polymer nanocomposites. Their nonlinear flow behavior was investigated in oscillatory shear via Fourier-transform (FT) rheology and Chebyshev polynomial decomposition. It was shown that in addition to an increase in the magnitude of nonlinearities with filler concentration, the electrical percolation threshold corresponds to a unique nonlinear rheological signature. Thus, in dynamic strain sweep tests, the nonlinearities are dependent on the applied angular frequency, potentially detecting the emergence of a weakly connected network that is being disrupted by the flow. This is valid for both the third relative higher harmonic from Fourier-transform rheology, I3/1, as well as the third relative viscous, v3/1, Chebyshev coefficient. The angular frequency dependency comprised non-quadratic scaling in I3/1 with the applied strain amplitude and a sign change in v3/1. The development of the nonlinear signatures was monitored up to concentrations in the conductor region to reveal the influence of a more robust percolated network.

Percolation

Hierachical graphene

Nonlinear oscillatory shear

Polymer nanocomposites

Författare

Roland Kádár

2D-Tech

Chalmers, Industri- och materialvetenskap, Konstruktionsmaterial

Karolina Gaska

University of Bristol

Thomas Gkourmpis

Borealis AB

Chalmers, Industri- och materialvetenskap, Konstruktionsmaterial

Rheologica Acta

0035-4511 (ISSN)

Vol. 59 5 333-347

Högpresterande och skalbara skräddarsydda grafen - polyolefin nanokompositer

VINNOVA, 2018-11-30 -- 2021-02-28.

Ämneskategorier

Teknisk mekanik

Textil-, gummi- och polymermaterial

Kompositmaterial och -teknik

Styrkeområden

Produktion

Materialvetenskap

DOI

10.1007/s00397-020-01204-w

Mer information

Senast uppdaterat

2020-09-10