Papers by Keyword: Lignosulfonate

Abstract: The high difference in surface tension between the filler and the polymer often constrains membrane compatibility. To reduce the surface tension, organosilane such as GPTMS is usually used to improve miscibility. In this study, GPTMS was introduced to produce lignin-GPTMS (LG) and lignosulfonate-GPTMS (LsG). The modification was done by reacting lignin and lignosulfonate with GPTMS using ethanol as the media. The product was characterized using Fourier Transform InfraRed (FTIR), X-ray Diffraction (XRD), Particle Size Analyzer (PSA), Scanning Electron Microscope-Energy Dispersive X-ray (SEM-EDX) and microscope. The success of functionalization was shown in FTIR spectra with the vibration of Si-O at 1034 cm^-1 and 528 cm^-1. The XRD analysis presents that the filler material has an amorph and crystalline structure. The functionalization using a 2:1 ratio increases zeta potential absolute and particle size due to the silane being a bridge and making a larger macromolecule. For a ratio of 1:1, a higher organosilane compound results in breaking siloxane linkages and making smaller molecules. Mixed LG and LsG into PVDF membrane conducted to analyze filler compatibility. The sulfonation and functionalization of GPTMS increase the compatibility of lignin in PVDF membrane with the best homogeneity achieved by a membrane with the addition of LsG 1:1.

Abstract: Alkali-activated materials are a low carbon alternative for Ordinary Portland cement in the building industry. However, the effectiveness of commercially available cementitious plasticizers is often an issue. The present study deals with the workability, setting time, and mechanical properties of alkali-activated blast furnace slag (AAS) systems with different addition of lignosulfonate plasticizer (0; 0.5 and 1.0%) and various concentrations of alkaline activator (sodium hydroxide with concentration of Na⁺ ranging from zero to 12 mol∙dm⁻³ was used for these purposes). The workability of AAS was determined using the slump test according to EN 1015-3. Then the Vicat apparatus as described in EN 196-3 was used for measurement of the setting time. The effect of activator dose and plasticizer addition on the mechanical properties was determined using the determination of compressive and tensile strength in bending. A positive effect of the addition of a plasticizer in a certain concentration range on the workability was observed, but at the same time, the setting time is prolonged. The optimal concentration of NaOH seems to be of 2–4 mol∙dm⁻³ regarding the development of mechanical properties and workability.

Abstract: The study of lime-based systems is vital to the design of new sustainable building materials. Air lime (calcium hydroxide, Ca (OH)₂) is a binder that has attracted considerable attention for its ability to capture CO₂ from the atmosphere, its low-cost and low-energy production process. Furthermore, Ca (OH)₂ is an important phase of hydrated Portland cements, and lime-based mortars have shown high elasticity and the ability of self-healing. The performance of lime-based building materials can be enhanced by the addition of organic compounds that can modify the mineralogy and microstructure of Ca (OH)₂. In this study, the effects of four biopolymers including starch, inulin, pectin, and calcium lignosulfonate, on the microstructure and mineralogy of lime have been investigated. Hydrated lime was produced by slaking quicklime in water. Two sets of hydrated lime batches were produced for each polymer: (i) the polymer was previously dissolved in water and subsequently mixed with lime, and (ii) the polymer was added as a dry powder to the already hydrated lime at the end of the slaking process. Characterisation of the batches was performed using scanning electron microscopy, X-ray diffraction and laser diffraction. Results indicate that biopolymers affect the nucleation and growth of Ca (OH)₂ crystals. This influences the microstructure and crystal aggregation of hydrated lime in colloidal suspension, which will have important implications on the use of biopolymers in Portland cement applications and in the use of lime as a binder for mortars.

Abstract: Sand erosion is a serious problem in the relatively arid and semiarid areas. A novel chemical sand fixing agent (LSUF) synthesized by lignosulfonate graft urea-formaldehyde was introduced in this study. It was made by polymerization of lignin sulfonate, urea and formaldehyde. The newly synthesized product had good water solubility, potentially good biodegradation, and produced no additional pollution. The results showed that the strength test, water-retaining test and wind erosion test of LSUF was better than the sand fixing agent composition by urea-formaldehyde (UF). The LSUF is an environment-friendly products and, it can be considered as an ideal sand fixing agents to control sand erosion in the relatively arid and semiarid areas.

Abstract: One of the most important problem of concrete durability is increasing of waterproofing. Researches are devoted studying of cement mortars modified by carbon nanotubes, dispersed in plasticizers solutions. Were investigated physico-mechanical properties of cement paste, cement-sand mortar into which structure entered untreated carbon nanotubes (production of plant TM "Spetsmash" Kyiv, Ukraine) in various quantity. Were used as plasticizers in cement compositions additives substances of the various chemical nature – naphtaleneformaldehyde, melamineformaldehyde and polycarboxylate. Quantity of untreated nanotubes varied from 0,5%; 1,0% and to 1,5%. Concentration of additives was accepted taking into account recommendations of producers and made about 1% from the weight of cement. Were studied some technological processes of introduction untreated carbon nanotubes in cement system and is shown that the way of introduction of nanomodifiers has essential impact on strength characteristics of cementitious materials. Optimum decision introduction of untreated carbon nanotubes is using its in dispersion plasticizer of the working concentration prepared in an ultrasonic dispergator is established. Results of physico-mechanical tests of cement paste and cement-sand mortar showed positive influence at introduction of untreated carbon nanotubes as cement modifiers on strength characteristics of samples. Resalts is shown that the nanomodifier, used quantity about 1% in solution of lignosulfonate with polycarboxylate and melamineformaldehyde plasticizer has great impact on strength characteristics.

Abstract: Rosin-modified lignosulfonates were prepared according to the following procedure: firstly, sulfomethylation of kraft lignin; secondly, preparation of 2,3-epoxypropyl ester of rosin; thirdly, preparation of modified-rosin lignosulfonates via etherification of sulfomethylated lignin with 2,3-epoxy propyl ester of rosin. Experimental results show that the optimum conditions for synthesis of 2,3-epoxy propyl ester of rosin are as follows: molar ratio for n(rosin): n (epichlorohydrin): n (NaOH) is1:6:1, reaction temperature is 100 °C(for rosin ester) and 75 °C(for 2,3-epoxypropyl ester of rosin, the same below), reaction time is 5.5 h and 3 h respectively. When molar ratio of lignosulfonate to 2,3-epoxypropylester of rosin is 1/5, rosin-modified lignosulfonates were prepared at 55 °Cfor 4.5 h with pH 11.5. Hydrophilic sulfonic group and the lipophilic adbietic group were incorporated into the molecular structure of kraft lignin via corresponding reactions. The surface tension of 10 g/L aqueous solution of rosin-modified lignosulfonate is 49.3 mN/m.

Abstract: Brake pads are composite materials which have been constantly improved by new materials that increase the quality and reduce the non-renewable raw materials. The goal of this work is to study the behavior of brake pads produced with replacement of phenol-formaldehyde resin by lignin up to 40% weight ratio. The Krauss method of characterization and SEM analysis were employed. The results showed an average friction coefficient approximately to μ_m=0.4 and a heterogeneous surface morphology. The satisfactory results are compatible with the current friction materials.

Abstract: High molecular weight lignosulfonate was oxidatively degrdadated into lower molecular weight fractions, the resulting components were conducted to formulate resol resin with phenol and formaldehyde in an alkaline condition, in which 50% phenol was substituted. The modified resol resin was successfully applied to prepare phenolic foam using appropriate combinations of flowing agents. N-pentane was found to be suitable as the foaming agent. Sulphuric acid (50% aqueous solution, w/w) and Tween-80 were used as catalyst and surfactant, respectively. The obtained foams showed satisfactory mechanical properties and excellent uniform cells, which can comply with the required specifications for its practical utilization.

Abstract: The characteristics of structural and properties of four sodium lignosulfonate (LS) fractions with narrow molecular weight (Mw) distribution isolated by gel column chromatography were investigated with infrared spectroscopy, elemental analysis, 13C NMR analysis, fluorescence spectroscopy and thermogravimetric analysis. LS with higher Mw possesses more aryl ring structural units and the side-chain of the structural unit is mostly composed of propanol rather than propane. With the increase of Mw of LS, the contents of sulfonic group and methoxy group decrease. The critical aggregation concentration (CAC) of LS aqueous solution was determined by fluorescence spectroscopy, which shows that the CAC of LS with higher Mw is lower, indicating that the LS molecule with low Mw is easier to aggregate. TGA results indicate that the weight loss of LS tends to be slow and the thermal stability enhances with the increase in Mw. The dispersive effect of LS with different Mw to dimethomorph suspension shows that the sediment layer thickness and index of dispersity and stability both decease with increasing Mw of LS, which indicates that LS with higher Mw has a better dispersion performance.

Abstract: The dispersive effect of four lignosulfonates (Kinsperse126, sodium lignosulfonate, magnesium lignosulfonate and a modified lignosulfonate GCL4-1) on the stability of Dimethomorph (DMM) water based suspension with different particle sizes was investigated. DMM suspension without dispersant was unstable owing to the strong aggregation of particles, while the stability was increased after the addition of lignosulfonate (LS), which can be adsorbed on the particle surface and weaken the aggregation of particles. Moreover, the higher sulfonated degree of LS, the better the dispersible ability was. Compared with LS of high sulfonated degree which could improve the zeta potential of DMM, LS with high molecular weight had larger adsorption capacity and steric effect on the pesticide particles. Associated with the dispersive behavior of DMM suspension, the electrostatic repulsion was found to be the more important factor impacting the stability of DMM suspension by comparison with the steric effect.