Transfer batch blending, an innovative solvent/solid assisted method for melt compounding to achieve good dispersion quality for polymer–clay-nanocomposites

Abstract

The specific interface area between filler and matrix is of key importance for the performance of nanocomposites and therefore blending methods that deliver the best possible dispersion quality, while at the same time being technically benign, are sought-after. Transfer batch blending, as proposed here, utilizes an organic separator compound that is highly volatile at melt compounding temperatures allowing for its easy removal, while being solid at room temperature allowing for easy handling and processing. As judged by particle size distributions for redissolved nanocomposites and TEM micrographs, the quality of dispersion achieved by this transfer batch blending is of comparably high quality as the quality achieved by solution blending and is clearly superior to the quality obtained by melt blending. Permeability was chosen as the nanocomposite property used to probe dispersion quality as achieved by the different blending methods. For both fillers applied, organically modified natural montmorillonites and synthetic hectorites, transfer batch blending consistently delivered significantly higher reductions of the permeability suggesting that higher effective aspect ratios are achieved via the improved dispersion quality by transfer blending as compared to melt blending.