Dissolving pulp from eucalyptus sawdust for regenerated cellulose products

Abstract

This study assesses the possibility of obtaining regenerated cellulose products (beads and lms) from eucalyptus sawdust dissolving pulps produced by non-conventional processes, compared with a commercial dissolving pulp as a reference. Eucalyptus sawdust dissolving pulps were obtained by soda pulping followed by two different TCF sequential bleaching processes OOpZ and OOp (where O is oxygen, Op is oxygen reinforced with hydrogen peroxide, and Z is ozone), followed by a cold soda extraction. The characterization of dissolving pulps involved alpha-, beta-and gamma-cellulose content, alkali solubility with 10 wt% (S 10 ), and 18 wt% NaOH (S 18 ) aqueous solutions, and degree of polymerization. Fock´s method was used to measure cellulose reactivity and the alkali solubility in a 9 wt% NaOH aqueous solution at -5 °C to evaluate the pulps dissolving capacity. Dissolving pulps presented high cellulose content (> 93 %, expressed as a-cellulose) and good reactivity (almost 84 %). The dissolving pulps were adequate raw materials for regenerated cellulose products (beads and lms) from two cellulose dissolution methods: direct dissolution in NaOH/urea and cellulose carbamate solution. The sequence OOpE (where E is an alkaline extraction) was determined to be a more economically feasible and straightforward process to produce dissolving pulp than OOpZE. The experimental pulps showed the expected characteristics of the dissolving pulp to obtain regenerated cellulose products. However, it is necessary to deepen the study of producing regenerated cellulose lms with enhanced mechanical properties from experimental dissolving pulps, solvents, coagulation, and regeneration conditions.

Dissolving-grade pulp: a sustainable source for fiber production

“…In most situations, pulps with lower degree of polymerization values exhibit higher cellulose dissolution (Wang et al 2006;Evangelina Vallejos et al 2022). A uniform MWD of the dissolving pulp is desirable in order to ensure homogenous reactions during the viscose process and provides improved mechanical properties of the final viscose fibers (Yang et al 2019).…”

“…They obtained filaments very similar in textile physical properties to viscose filaments with a decreased carbon disulfide (CS 2 ) input. Vallejos et al (2022) assessed the possibility of obtaining regenerated cellulose products such as beads and films by cellulose carbamate solution, using eucalyptus sawdust as a raw material. The sawdust was processed by soda pulping and TCF bleaching sequence with the purpose to achieve the characteristics of dissolving pulps.…”

Processes and Challenges for the Manufacturing of Lyocell Fibres with Alternative Agricultural Feedstocks

“…L-MMCF are manufactured from high alpha-cellulose feedstock, typically from eucalyptus or beech trees, bamboo, or cotton linters [6,24]. Researchers have also explored alternative feedstock sources such as industrial hemp (bast and hurd), sugarcane bagasse, kudzu, and corn cobs [7,[23][24][25][26]32,50]. Details on the L-MMCF process from traditional L-MMCF feedstocks (e.g., wood, bamboo, cotton linters) are provided here in addition to alternative agriculture feedstocks, specifically industrial hemp stalks, so that the utilisation of the traditional sources, specifically wood, can be contrasted to that of industrial hemp stalks.…”