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

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.