Using H2O2 to selectively oxidize recyclable cellulose yarn with high carboxyl content

Abstract

A novel and green approach was developed for the fabrication of oxidized recyclable cellulose (ORC) yarns by hydrogen peroxide with high carboxyl content (CC). Herein, recyclable cellulose (RC) yarn was pretreated by NaOH solution, then oxidized by H2O2/CuSO4 system to achieve ORC with CC ranging from 17.9 to 37.1%, depending on the H2O2/RC molar ratios used. The structure and morphology of ORC were carefully characterized by titration, intrinsic viscosity, XRD, FTIR, 13C-NMR, XPS, SEM and GC–MS, respectively. The degree of polymerization, yield and crystallinity of ORC were dependent on CC and varied in different directions. FTIR, 13C-NMR and XPS showed that the selective oxidation for the primary alcohol groups of cellulose was achieved. The results of XRD and SEM showed that oxidation would penetrate the yarn thoroughly and destroy its uniformity and length but not the crystal structure. GC–MS analysis revealed that some proportion of RC suffered hydrolysis and converted into soluble organic compounds. This study provided a green and facile approach to fabricate ORC with high CC by H2O2. A mechanism was proposed for the synchronous selective oxidation of the RC primary alcohol groups by H2O2.