Acid and alkali chemical treatments on synthetic and natural cellulosic, fibroin and keratin-based fabrics: study of structural changes

Abstract

The characterization of fabrics under after applying different degradation conditions appears to be a key factor to understand their behaviour for different applications. Depending on the treatment, morphologic and polymorphic changes can happen may arise in the polymeric chain structure of the that composes textile fibers made of polymeric chains. In this paper, a systematic and comparative study between different types of natural and synthetic textile fabrics has been carried out in order to clear up some shed light on the structural changes occurring under acid and basic alkali treatments. The natural fabric polymers studied have a cellulose-based composition from plants (cotton, linen and jute), or and a protein-based one from animals (silk and wool). The synthetic fabric was polyester. Different treatment times were assessed: 15 min, 1h, 2h, 4h, 8h and 24h and compared to the initial condition of the fabrics (standard). In the cellulosic fabrics, the alkali provoked the polymorphic transformation of the amorphous CI into CII. However, the acid treatment did not cause any remarkable alterations in the structures. In protein fabrics, the acid treatment increased the amorphicity of the structures, leading them to further higher degradation but not affecting the conformation of proteins, and the basic alkali dissolved the fabrics. Polyester was not affected by the chemical solutions (neither acid nor basis alkali).