Effects of Heat on Cotton, Polyester, and Wool Fibers in Blended Fabrics - A Scanning Electron Microscopy Study

Abstract

Treating cotton textile fabrics with phosphorus-containing flame retardant finishes reduces the flammability of the fabrics. The presence of fibers other than cotton in blended fabrics changes the burning rates and char lengths of the fabrics, as well as the nature of the resultant chars. To better understand the relationship of blended fibers during burning, and the response of each fiber to heat, scanning electron microscopy was used to study structures of blended cotton/polyester and cotton/ wool fabrics, and of individual fibers, both before and after exposure to flames. In blended fabrics, changes in physical structures of polyester and wool were observed before those in cotton. Chars of blended fabrics were more stable than those from either fiber alone, because the charred cotton formed a network onto which the melted polyester and wool could flow. These melts in turn protected and strengthened the cotton residue.