Characterization and control of oxidized cellulose in ramie fibers during oxidative degumming

Oxidative degumming with hydrogen peroxide provides an efficient pathway and new alternative for natural fiber extraction. In this work, the oxidized cellulose introduced into ramie fibers during the oxidative degumming process was systematically characterized in terms of x-ray photoemission spectroscopy, nuclear magnetic resonance, Fourier transform infrared spectroscopy and scanning electron microscopy. The differences of chemical components, chemical shift, surface structure and surface morphology were analyzed and compared within oxidized cellulose fibers with different oxidation degrees. In addition, the relationship between oxidized cellulose contents and mechanical properties of degummed fibers were further discussed. The results show that the number of oxidized groups increases with increasing oxidation. In addition, the greater presence of oxidized cellulose contributes to a larger loss of tenacity, breaking elongation, flexibility and degree of polymerization in degummed fibers. This study could offer useful information in better understanding the reaction characteristics of oxidative degumming and better control of degummed fiber quality. The contents of oxidized cellulose in ramie fibers could be an effective indicating factor to demonstrate oxidative degumming efficiency and fiber properties.