Effects of concentration and temperature on the rheological behavior of concentrated sodium lignosulfonate (NaLS) solutions

Abstract

Concentrated sodium lignosulfonate (NaLS) solutions have wide industrial applications. Therefore, the viscoelastic properties of NaLS in concentrations of 55%-63% have been investigated between 5°C and 55°C by means of a dynamic rheological technique, namely, the oscillatory rheological experiments were conducted in a rheometer in the small amplitude oscillatory mode. All solutions showed "shear-thinning" behavior over frequency. The complex viscosity (η*) increased and the loss tangent (tanδ) decreased with increasing concentrations. Both the storage modulus (G′) and the loss modulus (G″) increased with increasing frequencies and concentrations. The change in viscoelastic behavior was probably caused by stronger aggregation effects. However, the effects of temperature on the viscoelastic properties are more complex. For 60% NaLS, G′, G″, and η* decreased, but tanδ increased with increasing temperatures. When the temperature exceeded 20°C, G′, G″, and η* increased, but tanδ decreased, and the relaxation times were increased as a function of temperature. The change in viscoelasticity as a function of temperature may also be related to intermolecular aggregation and the swelling of aggregates. The conductivity experiments indicated that the formation of a greater strength of network structures at higher levels of concentrations between 55% and 63% and temperatures between 20°C and 55°C was probably responsible for elasticity enhancement.

Formation of Uniform Colloidal Spheres Based on Lignosulfonate, a Renewable Biomass Resource Recovered from Pulping Spent Liquor

“…The commercial NaLS, separated from the sulfite pulping spent liquor of poplar wood, was supplied by Shixian Papermaking Co. Ltd. (Jilin, China). The raw NaLS samples were processed by filtration and ultrafiltration to remove the low-molecular-weight impurities, and the detailed pretreatment process has been described in our previous work . Deionized water (resistivity ≥18 MΩ·cm) was obtained from a Millipore water purification system and used for the experiments conducted in this work.…”

“…The raw NaLS samples were processed by filtration and ultrafiltration to remove the low-molecularweight impurities, and the detailed pretreatment process has been described in our previous work. 7 Deionized water (resistivity ≥18 MΩ• cm) was obtained from a Millipore water purification system and used for the experiments conducted in this work. CTAB, EtOH and other chemical reagents were all purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China) and used as received without any further purification.…”

“…Lignosulfonate (LS) is a typical derivative of lignin obtained through the sulfite pulping process. , It is often recognized as an anionic surfactant, which contains both hydrophilic and hydrophobic groups, such as sulfonic, carboxyl, phenolic hydroxyl, aromatic, and aliphatic groups . Due to the favorable solubility and strong polyelectrolytic behavior, , LS has been widely used in various adsorption and dispersion fields, such as dispersants of dye, concrete, − pesticide, coal-water slurry, , oil well, and graphene, as well as cleaning agents, auxiliary substances for paper coating, corrosion and scale inhibitors for recirculating cooling water, and dopants for conductive polymers . Overall, these uses of LS are relatively ordinary and low value-added applications, and their market demand only accounts for a negligible fraction of the current worldwide LS production.…”

Effects of Cationic Cetyltrimethylammonium Bromide on the Aggregation Behavior of Sodium Lignosulfonate (NaLS) in Concentrated Solutions and Preparation of Uniform Lignosulfonate-Based Colloidal Spheres

“…The raw NaLS samples were purified and fractionated through filtration and ultrafiltration to remove the low-molecularweight impurities, and the detailed pretreatment process has been described in our previous work. 36 The sulfonic group content of the purified NaLS sample was measured to be 1.29 mmol g −1 , which was conducted on an automatic potentiometer titrator (809 Titrando; Metrohm Corp., Switzerland) according to the conductometric titration method. 37 Deionized water (resistivity ⩾ 18 MΩ•cm) was obtained from a Millipore water purification system and used for the following experiments.…”

Very Strong, Super‐Tough, Antibacterial, and Biodegradable Polymeric Materials with Excellent UV‐Blocking Performance

“…LS is rich in hydrophilic hydroxy and sulfonic acid groups and also contains the hydrophobic phenylpropane structure, which has been widely used as a dispersing agent . The polar functional groups in TA and LS can promote the adsorption of Ag ions . Introducing TA as a natural reducing agent and LS as a green carrier to prepare silver‐containing antibacterial agent not only ensures good interfacial compatibility with PVA but also realizes the high‐value utilization of biomass resources.…”