A knowledge of filament, matrix, and void content is generally required in order to characterize and study composite materials. It is difficult to obtain such data for Kevlar 49/epoxy composites due to chemical attack of the Kevlar filaments when techniques developed for other composite systems are used. This paper presents a chemical dissolution technique for Kevlar 49/epoxy composites by which less than one percent loss of the filament weight occurs. The procedure involves swelling the epoxide matrix in hot dimethylsulfoxide and then rapidly dissolving the degraded epoxide in a nitric aciddimethylsulfoxide solution. This technique allows the determination of filament, matrix, and void volume fractions of Kevlar 49/epoxy composites with a single procedure and has been successfully applied to fabric and filament‐wound composites and to a variety of epoxides. Results obtained with this dissolution technique show excellent agreement with those from optical and weight‐difference methods. Copyright © 1979 Society of Plastics Engineers, Inc.
