Quantifying Nanoparticle Dispersion using Rheological Techniques in Epoxy Resin

Summary

In nanodielectric technology the ability to uniformly disperse nanoparticles in the host matrix is critical to the quality of the nanodielectric. Due to the nanometre size of the filler particles, their tendency to agglomerate or flocculate is high. Currently many flaws in nanodielectrics have been attributed to the presence of agglomerations. The current state of the art techniques used in determining the uniformity of nanoparticle dispersion is largely based on the use of electron microscopy, such as Transmission Electron Microscopy and Scanning Electron Microscopy. A limitation with these imaging techniques is that the assessment is largely qualitative rather than quantitative. Additionally these techniques rely on the ability to manufacture a nanodielectric before the degree of dispersion can be evaluated. The present paper investigates the use of rheological techniques to assess the uniformity of dispersion within the host matrix. Rheology is based on the principle of correlating viscosity with varying rotational speed of the fluid. Agglomerations significantly alter the output plot of the rheometer in comparison with that of uniformly dispersed nanoparticles. The rheological methodology was tested for 2 wt%, 4 wt% and 8 wt% of Boron Nitride in Epoxy (Araldite CY 231-1). The viscosity characteristics of Araldite showed that 4 wt% was better dispersed than 2 wt% and 8 wt% and was validated through Scanning Electron Microscopy. Future improvements discuss that assessments of rheology for different mixing and dispersing techniques and at different stages of the manufacturing procedure are needed.

Additional informations

Authors

Faria da Silva Filipe, Endahl Brian, Alzatari Mazen, Hirsch Holger