Rheological Characterization of Nano Silica Dispersion in Polyethylene

C.R. López-Barrón, S. Luo, A.H. Tsou
ExxonMobil Chemical Company, US

Keywords: grafted silica, rheology, percolation, dispersion, activation energy

Summary:

The state of aggregation of silica nanoparticles (both grafted and non-grafted) in polyethylene was studied via linear rheology thermal-mechanical spectroscopy, small-angle neutron scattering and microscopy. A novel method to determine the state of aggregation based on the analysis of the flow activation energy was developed. Furthermore, it was found that a better dispersion is obtained by grafting polyethylene molecules onto the silica surface. However the local percolation of individual silica paricles was noit affected by grafting.