Surface Analyses of Carbon Fibers Produced from Polyacrylonitrile Fibers at Low Carbonization Temperatures

Abstract

A process for producing carbon fibers from polyacrylonitrile at low carbonization temperatures was studied. The bulk and surface properties of fibers obtained after reaction with benzoic acid, air, and carbonizing in nitrogen or a dilute acetylene atmosphere are discussed. All fiber products had different surface and internal com positions. Samples produced at temperatures up to 950°C and carbonized in nitrogen contained substantial quantities of nitrogen and oxygen at the surface. During car bonization, the surface nitrogen converted into two new forms, possibly nitrile and an azo or a new carbon-nitrogen bond. Samples carbonized in acetylene contained a carbon-rich surface stable to oxidation.