Influence of the filler distribution on PDMS-graphene based nanocomposites selected properties

Insufficient homogeneity is one of the pressing problems in nanocomposites' production as it largely impairs the properties of materials with relatively high filler concentration. Within this work, it is demonstrated how selected mixing techniques (magnetic mixer stirring, calendaring and microfluidization) affect filler distribution in poly(dimethylsiloxane)-graphene based nanocomposites and, consequently, their properties. The differences were assessed via imaging and thermal techniques, i.a. Raman spectroscopy, differential scanning calorimetry and thermogravimetry. As microfluidization proved to provide the best homogenization, it was used to prepare nanocomposites of different filler concentration, whose structural and thermal properties were investigated. The results show that the concentration of graphene significantly affects polymer chain mobility, grain sizes, defect density and cross-linking level. Both factors considered in this work considerably influence thermal stability and other features which are crucial for application in electronics, EMI shielding, thermal interface materials etc.