Effect of particle shape at finite concentration on thermal expansion of filled polymers

Abstract

AbstractRelations are derived for the linear and volumetric thermal expansion coefficients of a filled polymer containing aligned ellipsoidal inclusions at finite concentrations. The analysis follows a procedure recently developed for elastic moduli by application of a generalized approach of Eshelby. The well‐known Kerner equation is shown to be a limiting case of the present finding. From data on glass in epoxy resin, we conclude that the volumetric expansion varies only slightly with the aspect ratio of an ellipsoid; however, the longitudinal and transverse, linear, expansions show a strong dependence on the particle shape.