Rheological study of interactions between non-ionic surfactants and polysaccharide thickeners used in textile printing

Regioselective palladium-catalysed aerobic oxidation of dextran and its use as a bio-based binder in paperboard coatings

The coatings industry is aiming to replace petrochemical-based binders in products such as paints and lacquers with bio-based alternatives. Native polysaccharide additives are already used, especially as adhesives, and here we show the use of oxidised dextran as a bio-based binder additive. Linear dextran with a molecular weight of 6 kDa was aerobically oxidised in water at the C3-position of its glucose units, catalysed by [(neocuproine)PdOAc]2(OTf)2. The resulting keto-dextran with different oxidation degrees was studied using adipic dihydrazide as a crosslinker in combination with the commercial petrochemical-based binder Joncryl®. Coating experiments show that part of the Joncryl® can be replaced by keto-dextran while maintaining the desired performance.

Properties of galactomannans and their textile-related applications-A concise review

Galactomannans are reserve carbohydrates in legume plants and are primarily extracted from their seeds. They contain galactose side chains throughout the mannose backbone and have unique features such as emulsifying, thickening, and gelling together with biodegradability, biocompatibility, and non-toxicity, which make them an appealing material. Guar gum and locust bean gum mainly are used in all galactomannan needed applications. Nonetheless, tara gum and fenugreek gum have also attracted considerable attention in recent decades. Despite the increased usage of galactomannans in the textile-related fields in recent years, there is no review article published yet. To fill this gap and to demonstrate the striking and increasing importance of galactomannans, a concise summary of the properties of common galactomannans and their comparisons is given first, followed by an account of recent developments and applications of galactomannans in the textile-related fields. The associated potential opportunities are also provided at the end of this review.

Extraction of Natural Gum from Cold-Pressed Chia Seed, Flaxseed, and Rocket Seed Oil By-Product and Application in Low Fat Vegan Mayonnaise

This study involves the modeling of rheological behavior of the gum solution obtained from cold-pressed chia seed (CSG), flaxseed (FSG), and rocket seed (RSG) oil by-products and the application of these gums in a low-fat vegan mayonnaise formulation as fat replacers and emulsifier. CSG, FSG, and RSG solutions showed shear-thinning flow behavior at all concentrations. The K values ranged between 0.209 and 49.028 Pa·sⁿ for CSG, FSG, and RSG solutions and significantly increased with increased gum concentration. The percentage recovery for the G′ was significantly affected by gum type and concentrations. CSG, FSG, and RSG showed a solid-like structure, and the storage modulus (G′) was higher than the loss modulus (G″) in all frequency ranges. The rheological characterization indicated that CSG, FSG, and RSG could be evaluated as thickeners and gelling agents in the food industry. In addition, the rheological properties, zeta potential, and particle size and oxidative stability (at 90 °C) of low-fat vegan mayonnaise samples prepared with CSG, FSG, and RSG were compared to samples prepared with guar gum (GG), Arabic gum (AG), and xanthan gum (XG). As a result, CSG, FSG, and RSG could be utilized for low-fat vegan mayonnaise as fat and egg replacers, stabilizers, and oxidative agents. The results of this study indicated that this study could offer a new perspective in adding value to flaxseed, chia seed, and rocket seed cold-press oil by-product.

Enhancing Lignin Dissolution and Extraction: The Effect of Surfactants

The dissolution and extraction of lignin from biomass represents a great challenge due to the complex structure of this natural phenolic biopolymer. In this work, several surfactants (i.e., non-ionic, anionic, and cationic) were used as additives to enhance the dissolution efficiency of model lignin (kraft) and to boost lignin extraction from pine sawdust residues. To the best of our knowledge, cationic surfactants have never been systematically used for lignin dissolution. It was found that ca. 20 wt.% of kraft lignin is completely solubilized using 1 mol L-1 octyltrimethylammonium bromide aqueous solution. A remarkable dissolution efficiency was also obtained using 0.5 mol L-1 polysorbate 20. Furthermore, all surfactants used increased the lignin extraction with formic acid, even at low concentrations, such as 0.01 and 0.1 mol L-1. Higher concentrations of cationic surfactants improve the extraction yield but the purity of extracted lignin decreases.

Rheological properties of a β-1,3-polyglucuronic acid derivative from 4-acetamido-TEMPO-mediated oxidation of curdlan

The rheological properties of a carboxylic curdlan bearing a β-1,3-polyglucuronic acid structure were investigated as a function of concentration and temperature.

Effect of carboxymethylation on rheological and drug release characteristics of locust bean gum matrix tablets

This study was undertaken to investigate correlation between the carboxymethylation-induced rheological changes and drug release characteristics of locust bean gum (LBG) matrix tablets. LBG was derivatized to carboxymethyl LBG (CMLBG) and characterized by (13)C NMR, FTIR and elemental analyses. Rheological studies revealed that LBG, in contact with water, produced a strong elastic gel which swelled less due to lower penetration of water resulting in slower drug release. On the other hand, CMLBG formed a viscous polymer solution through which higher influx of water resulted in rapid swelling of the matrix and faster drug release. Although the release from a particular matrix was dependent on drugs' solubilities, CMLBG matrix tablet produced faster release of all the drugs than LBG matrix tablets. In conclusion, rheological study appeared to be an useful tool to predict release of drugs from polysaccharide matrix tablets.

A novel alkali and cosolvent thickening mechanism for latex

In this study, alkali-swellable acrylic latex (resin) and coalescent ethylene glycol butyl ether were combined to thicken the coating without the use of any thickeners.

The rheological properties of tara gum (Caesalpinia spinosa)

The rheological properties of tara gum, as affected by concentration, temperature, pH and the presence of salts and sucrose, were investigated by using steady and dynamic shear measurements and atomic force microscope observation. Tara gum exhibited non-Newtonian, pseudoplastic behaviour without thixotropy at tested concentrations (0.2-1.0%, w/v). Salts (CaCl2 and NaCl) led to a viscosity reduction, which was more sensitive to Ca(2+) than to Na(+). The gum had stable viscosity over a wide pH range (pH 3-11), and the influence of sucrose was concentration dependent. Increasing temperature from 20°C to 80°C decreased the gum viscosity. Frequency sweeps indicated that tara gum (1.0% w/v) behaved as a liquid at low frequency, and acted more like a gel at high frequency. With the decrease of concentration, tara gum may show a viscous property rather than an elastic one. These results are potentially useful for the application of tara gum in food processing.

The Fractional derivative rheological model and the linear viscoelastic behavior of hydrocolloids

This study was aimed at evaluating the possibility to use the Friedrich-Braun fractional derivative rheological model to assess the viscoelastic properties of xanthan gum with rice starch and sweet potato starch. The Friedrich-Braun fractional derivative rheological model allows to describe viscoelastic properties comprehensively, starting from the behaviour characteristic of purely viscous fluids to the behaviour corresponding to elastic solids. The Friedrich-Braun fractional derivative rheological model has one more virtue which distinguishes it from other models, it allows to determine the relationship between stress and strain and the impact of each of them on viscoelastic properties on the tested material. An analysis of the data described using the Friedrich-Braun fractional derivative rheological model allows to state that all the tested mixtures of starch with xanthan gum form macromolecular gels exhibiting behaviour typical of viscoelastic quasi-solid bodies. The Friedrich-Braun fractional derivative rheological model and 8 rheological parameters of this model allow to determine changes in the structure of the examined starch - xanthan gum mixtures. Similarly important is the possibility to find out the trend and changes going on in this structure as well as their causes.

Interaction of gums (guar, carboxymethylhydroxypropyl guar, diutan, and xanthan) with surfactants (DTAB, CTAB, and TX-100) in aqueous medium

The interaction of surfactants dodecyltrimethylammonium bromide (DTAB), cetyltrimethylammonium bromide (CTAB), and p-tert-octylphenoxypolyoxyethylene (9.5) ether (TX-100) with guar (Gr), carboxymethylhydroxypropyl guar (CMHPG), diutan (Dn), and xanthan (Xn) gums has been studied employing conductometry, tensiometry, microcalorimetry, viscometry, and atomic force microscopy (AFM) techniques. Both weak and strong interactions were observed. CTAB interacted stronger than DTAB with the gums. The surfactant-gum interaction process was enhanced by the presence of borate ions in the solution; the borate ion itself also manifested interaction with the surfactants comparable with that of water-soluble polymers polyvinyl alcohol, polyoxyethylene, and so forth. Viscometric results supported configurational changes of the gum molecules by interaction with surfactants. The geometry of the pure gums and their CTAB interacted products in the dried states was ascertained from AFM measurements; spherical and prolate shapes were observed for pure gums, and distorted states were observed for their surfactant complexed species. Detailed topological features of these entities were ascertained.

Not all anionic polyelectrolytes complex with DTAB

The influence of hydroxypropyl guar (HPG), with and without boric acid, on dodecyltrimethyl ammonium bromide (DTAB) micellization was characterized by surface tension measurements, isothermal titration calorimetry, and small-angle neutron scattering. Although HPG is a nonionic water-soluble polymer, borate ions form weak bonds with HPG, transforming it into an anionic polyelectrolyte, HPG-borate. Surprisingly, the three independent measurements showed that HPG-borate does not promote DTAB micellization or phase separation normally seen when mixing oppositely charged polyelectrolytes and surfactants. However, the neutron scattering results suggested that HPG-borate binds to and flocculates existing DTAB micelles. The unusual behavior of HPG-borate with DTAB was underscored by showing that carboxymethyl guar (CMG) formed precipitates with DTAB.