In this work, improved electro-mechanical properties of silicone-based dielectric elastomers are achieved by means of adding so-called "voltage-stabilisers" prepared from phenyl-functional copolymers prepared using oxyanionic ring-opening polymerisation of octamethylcyclotetrasiloxane (D4) and either tetramethyltetraphenylcyclotetrasiloxane (T4) or octaphenylcyclotetrasiloxane (O4). The concentration of the voltage stabiliser was varied both by changing the molar ratio between methyl and phenyl groups in the copolymer and also by varying the amount of copolymer mixed into a PDMS-based elastomer. The phenyl-functional copolymers were generally found to disperse homogeneously in the PDMS matrix and this resulted in networks with improved mechanical and electrical properties. The developed elastomers were inherently extensible with enhanced tensile and tear strengths, due to phenyl-rich microphases acting as reinforcing domains. Furthermore, addition of phenyl-functional copolymers resulted in elastomers with increased relative permittivity and electrical breakdown strength compared to control elastomers while retaining a low dielectric loss. This demonstrates their efficiency as voltage stabilisers.a Phenyl content based on the added phenyl copolymer. b Residual mass fraction of the lm aer extraction and drying. c Mass fraction of the added phenyl copolymer. d Mass fraction of the phenyl copolymer in the extract, calculated from 1 H NMR. e Peak molecular weight of the early eluting peak. f Peak molecular weight relative to the late eluting peak.
Downsizing medium or high voltage equipment requires the optimization of electric field distributions in the device and in the surrounding environment in order to master local high electric field strengths leading to partial discharges along the surface of the dielectric materials, prompting accelerated material ageing or in worse case dramatic failure. The purpose of this paper aims to compare for a cable termination both strategies namely resistive and capacitive (or dielectric refractive) field grading material where electrical passive or active fillers of same permittivity are respectively added to an insulation host matrix. Under both AC and transient regime, nonlinear resistive field grading shows a better effectiveness as far as electric stress control is of concern.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.