Preparation and characterization of dissolving pulp and lyocell fibers from corncob

In this study, dissolving pulp was prepared from corncob via alkali extraction, kraft cooking, metal ion removal, and H2O2 bleaching. Two cooking schemes were used to prepare unbleached corncob pulp samples with degrees of polymerization of 735 and 565. Employing an acid treatment with sodium ethylenediamine tetraacetate (EDTA) and sodium hexametaphosphate (SHMP) effectively reduced the ash and iron contents of the pulp; the optimal treatment conditions were pH 1.5, 0.4 wt% EDTA, and 0.4 wt% SHMP, which afforded pulp with iron and ash contents of 8.5 ppm and 0.02 wt%, respectively. A single-factor experiment was used to study the effects of H2O2 dosage and bleaching time on the brightness of the obtained pulp. The optimal bleaching parameters were determined as an H2O2 dosage of 3 wt% and a bleaching time of 70 min, which led to a brightness value greater than 82%. Fourier transform infrared spectroscopy and scanning electron microscopy results confirmed that the main component of corncob pulp was cellulose, and the fiber adopted twine-like morphologies with numerous spiral folds on the surface. The wet corncob pulp was used directly as the raw material for spinning lyocell fibers, and the results indicated that the corncob pulp had good spinnability.