Characterization of Polymer Layered Silicate Nanocomposites by Rheology and Permeability Methods: Impact of the Interface Quality

Rémi Waché,Serge Gonzalez,Marie-Hélène Klopffer

doi:10.2516/ogst/2013196

Abstract

Polymer clay nanocomposites are mostly described as materials with improved properties. However, many studies are not concluding about the possible benefits. This work reports permeability measurements on different polyolefins nanocomposites. Clay exfoliation has been proved by various techniques. Unfortunately, the nanocomposite does not exhibit good barrier properties. Hence, permeability coefficients were found to increase. A poor quality of the interface between filler and medium is likely to be responsible for this degradation. Insufficient interactions between silicate layers and the surrounding polymer lead to preferential pathways for diffusion. Organoclay exfoliation does not necessarily lead to better barrier properties. A good quality of the interface between polymer and filler is required to reach a high performance level. The standard techniques used to characterize exfoliation degree do not permit to highlight this kind of phenomena.

Highlights

Many current studies deal with the enhancement of physical properties that are achieved with nanocomposites compared to their neat matrix or to conventionally filled polymers systems [1,2,3,4,5,6,7,8,9]
The exfoliation of the clay has been proven by various techniques such as X-Ray Diffraction, Transmission Electronic Microscopy in a PEgMA matrix and in a compatibilized polyethylene matrix
A poor quality of the interface between the filler and the medium will induce a lower resistance for fluid transport and is likely to be responsible for those results

Summary

Introduction

Many current studies deal with the enhancement of physical properties that are achieved with nanocomposites compared to their neat matrix or to conventionally filled polymers systems [1,2,3,4,5,6,7,8,9]. Smectites are swelling clays made of stacked platelets of one nanometer thick each. They constitute an ideal filler for the synthesis of nanocomposite, requiring the chains of polymer to intercalate and swell the clay layers. Exfoliation of the clay platelets in the polymer matrix is the key parameter which will greatly modify the properties. The microstructure is commonly seen as the Grail for the enhancement of the properties, with the shortcut that an exfoliated state can be only possible with a good interface between the polymer and the clay. The aim of this paper is to understand the mechanisms of such undesirable phenomena

Objectives

Methods

Conclusion