Alkaline Peroxide Extrusion Pulping of Cotton Bast and Cotton Stalk

Abstract

The chemical compositions of cotton stalk and bast are similar to those of hardwood and superior to those of grass fiber. With respect to the morphological characteristics of their fibers, cotton stalk is similar to hardwood and cotton bast is similar to softwood. The average length of cotton bast fibers is nearly triple that of cotton stalk fibers, and the length-to-width ratio is almost quadruple. Traditionally, cotton stalk and cotton bast are pulped together, which affects the quality and homogeneity of the pulp and complicates bleaching, limiting its use to low-grade paper. In this study, cotton bast and cotton stalk were separated and pulped individually by alkaline peroxide extrusion pulping (APEP). The orthogonal analytical method was used to determine the optimal pulping parameters. Compared to those obtained via the kraft pulp (KP) of cotton stalk as a whole, far superior yield and whiteness were obtained in APEP. Further, with APEP, lower amounts of chemicals and less energy were consumed and there was little pollution. The physical performance of APEP was slightly lower than that of KP. With respect to bast alone, the physical performance of APEP was almost as good as that of KP.

Investigation of mechanical properties of cotton stalk based on multi-component analyses

“…Cotton stalk is the primary by-product of cotton production, and is rich in cellulose, lignin, and crude protein (Li et al, 2018), it is an important supplement to resource utilization in the form of biochar (Chen X. et al, 2015;Hou et al, 2014;Hu et al, 2014). According to the China Statistical Yearbook, in 2019, the sown area of cotton in China was 3.3392 × 10 6 ha, and the total yield was 5.889 × 10 6 t, of which Xinjiang accounted for 76.08% of the total and is therefore the main cotton plantation area in China.…”