Optimizing cellulose microfibrillation with NaOH pretreatments for unbleached Eucalyptus pulp

Abstract

This study aimed to assess the effect of drying unbleached Eucalyptus cellulose fibers after the application of pretreatments in order to optimize the microfibrillation process, as well as to evaluate the efficiency of NaOH pretreatments in reducing energy consumption for production of microfibrillated cellulose (MFC). Pretreatments with 0 wt% (untreated), 5 wt% and 10 wt% NaOH were evaluated. The length and width of the fibers pretreated with NaOH decreased significantly, mainly with hasher pretreatments.The removal of hemicellulose from the fiber cell wall was an important factor concerning the degree of fibrillation of the fibers. Pretreating fibers with 5 wt% NaOH for 2 h increased the water retention value (WRV), in addition to presenting the lowest energy consumption for fibrillation, promoting energy savings of up to 48%. Pulps that were not dried after the NaOH pretreatments incurred in easier microfibrillation and lower energy consumption when comparing to the dried pulp, which shows the negative impact of drying on the fibers to obtain the MFC.

Jute textiles with enhanced interfacial bonding as reinforcement for cementitious composites

“…Additionally, the alkaline treatment of the fiber surface contributes to its roughness or fibrillation, higher flexibility, and enhanced chemical homogeneity, promoting better compatibility between the fiber and the matrix. 67,68 Overall, adding micro silica powder coating has a minimal effect on the uncracked modulus of elasticity since this property is mainly governed by the stiffness of the inorganic matrix. 30 Similarly, the jute reinforcement itself, despite any modifications, has limited influence on the modulus of elasticity.…”

Effects of Lipase and Xylanase Pretreatment on the Structure and Pulping Properties of Wheat Straw

“…After lipase pretreatment, the fat and wax on the surface of the wheat straw were removed, making it easy for chemical reagents to penetrate into the inside of the pulp fibers, promoting the removal of lignin and improving the softness of the fibers. Therefore, the cutting of the fibers was reduced during beating and the fiberization, water absorption and swelling of the fibers were improved [ 43 ]. Additionally, the specific surface area of the fibers increased and more hydroxyl groups were exposed on the fiber surface, thus increasing the binding strength between the fibers.…”