Materials World Network: US/UK Collaboration on Nanocomposites for Electrical Insulation

Completed

Other Power and Storage Technologies(Electric power conversion)
Other Power and Storage Technologies(Electricity transmission and distribution)

Basic and strategic applied research

PHYSICAL SCIENCES AND MATHEMATICS (Chemistry)
PHYSICAL SCIENCES AND MATHEMATICS (Metallurgy and Materials)

Not Cross-cutting

Professor J C Fothergill
Department of Engineering
University of Leicester

Standard

EPSRC

15 August 2009

14 August 2012

36 months

£1

No relevance to Underpinning Sectors

East Midlands

Physical Sciences

Professor J C Fothergill, Department of Engineering, University of Leicester

SummaryWe propose an integrated experimental and analytical program to investigate the fundamental mechanisms leading to the significantly higher breakdown strength and voltage endurance (i.e. tme-to-breakdown) observed in polymer nanocomposites. Recent results by this team and others have shown that the addition of nanoscale spherical fillers to traditional insulation materials (epoxy, crosslinked polyethylene) can lead to significant improvements in these properties while maintaining desirable loss properties. These results are exciting and leading to focused commercial interest.However, our ability to tailor the response in these materials is limited by a lack of fundamental understanding of the role of the fillers and the surrounding interfacial region in improving the dielectric response. Our goal, therefore, is to understand the role of the extremely large surface area created by "nanofillers", and, by gaining this fundamental understanding be able to design nanofilled polymers with optimized properties in an informed way. From prior work, we hypothesize a qualitative mechanism leading to the improved properties. It remains, however, to quantify this behaviour and to conduct systematic studies of the role of interface chemistry, polarity and geometry on these mechanisms. As such, the experimental portion of this proposal will address the effect of silica nanofillers (with interfaces modified to control the enthalpic interaction with the matrix, the polarity, and the conductivity of the interface) on the dielectric behaviour. The role of surface curvature (particle size) and geometry (equiaxial vs. elongated) will also be investigated. We will systematically probe the dielectric response as a function of the interface condition using dielectric spectroscopy, electroluminescence, thermally stimulated current, pulsed electro-acoustic (space charge) measurements, and conductivity. We will augment the dielectric studies with careful microstructural, thermal and chemical characterization.To understand the experimental results and provide an analytical framework for future design, models are required that include size effects as well as the properties of the interfacial region. Based on our hypothesized mechanism, we propose to develop quantitative models for permittivity, conductivity, and breakdown. This coupled approach will provide the necessary quantitative information to begin informed design of these extremely interesting materials, which will maximize the opportunity for significant commercial impact. The international collaboration is critical to the success of the proposed work because of the combination of modelling expertise (UK), experimental expertise (UK and US) and both electrical and materials perspectives (US and UK) that is necessary to gain the critical fundamental understanding required to optimize these materials.This work will not only impact the development of nanoparticle filled polymer composites for a sector oftechnology that is critically important (power production and transmission), but will guide the design and development of nanocomposites in general, particularly applications where the role of the interface behaviour is critical. The commercial viability of these materials is already under investigation and thus the propensity for technological and commercial impact is high.Students on this project will not only be trained in nanomaterials for power applications, but will have had an international experience spending at least 6 months in the UK or US

11/11/11