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Transmission and backscattering for the system: MnO 2 /0.1 M NaCl/ 100 ppm GG/0.0001 M TX100, pH = 7
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Stability of the manganese dioxide (MnO2) suspensions by non-ionic guar gum (GG) in the absence or presence of the surfactants: anionic sodium dodecyl sulphate (SDS), cationic hexadecyltrimethylammonium bromide (CTAB) and non-ionic Triton X-100 (t-octylphenoxypolyethoxyethanol) and their equimolar mixtures (SDS/TX-100; CTAB/TX-100) was measured usi...
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This paper researched the influence of the polysaccharide polymer sodium alginate (SAG) on the depression of talc at a fixed room temperature about 25 °C through micro flotation and batch flotation experiments, zeta potential and contact angle measurements as well as infrared spectroscopy analysis. The flotation results displayed that the SAG had a...
Citations
... Borax cross-linked guar gel has three-dimensional network structures, a multi-stimulus response, and high self-healing properties, which can be used in many fields [16][17][18]. It has been reported that guar gum can be combined with surfactant or polymer [19] to prepare colloidal systems as emulsifierstabilized emulsions [20], but there are few reports on the preparation of emulsions with borax cross-linking guar gum. Theoretically, the good film-forming property of guar gel is conducive to the coverage of the emulsion droplets, and the three-dimensional network structure is beneficial for improving the stability of the emulsion. ...
The aim of the present study was to investigate highly efficient alkyl ketene dimer (AKD) emulsions to improve the hydrophobicity of cellulose paper. AKD emulsions stabilized by guar gel were obtained; the guar gel was prepared by hydrogen bond cross-linking sodium tetraborate and guar gum. The cross-linking was confirmed by combining FTIR and SEM. The effect of guar gel on the performance of the AKD emulsions was also studied by testing AKD emulsions stabilized by different guar gel concentrations. The results showed that with increasing guar gel concentration, the stability of the AKD emulsions improved, the droplet diameter decreased, and the hydrophobicity and water resistance of the sized packaging paper were gradually enhanced. Through SEM, the guar gel film covering the AKD emulsion droplet surface and the three-dimensional structure in the aqueous dispersion phase were assessed. This study constructed a scientific and efficient preparation method for AKD emulsions and provided a new method for the application of carbohydrate polymer gels which may avoid the adverse effect of surfactant on paper sizing and environmental problems caused by surfactant bioaccumulation.
... The stability of MnO 2 suspensions under various conditions has been studied intensively in previous works. 15 In this study, the 5 mg MnO 2 /0.1 M NaCl/100 ppm Guar gum/0.0001 M SDS + Triton X-100 mixture composition afforded the highest stability. ...
... In agreement with previous studies, only 5 mg of MnO 2 was used to achieve the best dispersion stability. 15 ...
Microfluidically synthesized anisotropically-shaped micromotors with concave dimple, embedded with MnO 2 and graphene oxide, exploit their autonomous motion to successfully capture and remove organic dye molecules from an aqueous environment.
... Borax cross-linked guar gel has threedimensional network structures, multi-stimulus response, and high self-healing properties, which can be used in many elds ; Thombare et al. 2017;Deng et al. 2015). It has been reported that guar gum can be combined with surfactant or polymer (Grządka 2014) to prepare colloidal systems as emulsi er-stabilized emulsions (Sokhal et al. 2019), but there are few reports on the preparation of emulsions with borax cross-linking guar gum. Theoretically, the good lm-forming property of guar gel is conducive to the coverage of the emulsion droplets, and the three-dimensional network structure is bene cial for improving the stability of the emulsion. ...
To improve the sizing efficiency of alkyl ketene dimer (AKD), we obtained AKD emulsions (AKDEs) stabilized by guar gel prepared by hydrogen bond cross-linking sodium tetraborate and guar gum in this work. The cross-linking was confirmed by combining FTIR and SEM. The effect of guar gel on the performance of the AKDEs were also studied by testing AKDEs stabilized by different guar gel concentrations. The results showed that with increasing guar gel concentration, the stability of the AKDEs improved, the droplet diameter decreased, and the hydrophobicity and water resistance of the sized cellulose paper were gradually enhanced. Through SEM, the guar gel film covering the AKDE droplet surface and the three-dimensional structure in the aqueous dispersion phase were assessed. This study constructed a scientific and efficient preparation method for AKDEs and provided a new method for the application of carbohydrate polymer gels.
... Conductometric analysis of GG and SLS mixtures has not demonstrated the formation of aggregates between both molecules [12]. However, the addition of GG to the MnO 2 suspensions, in presence of SLS, increased the adsorption of GG in the particle surface, promoting an increase of stability, due to multilayer complex formation, as speculated by the authors [22]. ...
... Therefore, this result confirms that EO groups from SLES could improve the surfactant interaction with GG in solution. Grzadka [22] observed that in the mixtures of SLS, GG and MnO 2 suspensions could form a multilayer complex at solid interface, suggesting that at specific conditions SLS and GG could interact. ...
... The interaction of GG with SLES non-ethoxylated form (SLS) was also analyze in other studies [12]. Grazadka [22] suggested some interaction between SLS and GG in presence of MnO 2 , however, in our experiments the aggregation was observed only between GG and SLES in according to Mukherjee et al. [12]. Apparently, the presence of EO groups favored the interaction. ...
The interaction between galactomannans, guar gum(GG)with sodiumlauryl ether sulphate (SLES)was demonstrated using conductometric, tensiometric, pyrene probe and 1H NMR analyses. SLES and GG formed aggregates and reduced the surface tension at a critical aggregation concentration. The interaction was attributed to the presence of surfactant ethoxyl (EO) groups, since in conductometric, tensiometry and pyrene probe analyses
using the non-ethoxylated form, sodium lauryl sulphate – SLS, no aggregation was observed. The aggregates formed between SLES and GG presented a negative zeta potential indicating that the polymer is surrounded by SLES and according to the dynamic light scattering analysis (DLS), presented a size of approximately 26 nm. The determination of the thermodynamic parameters showed that the aggregation occurs spontaneously and
is a driven-enthalpy and entropy process. SLES and GG interaction could be explored to produce formulations with lower concentrations of surfactants, using commonly used thickeners as GG.
... PVP in the synthesis of Au-Ag nanoalloys functions as a capping agent to make nanoparticles are stable. Nanoparticles are unstable and tend to agglomerate because at short interparticle distances, and they are attracted to each other by van der Waals attraction forces [20]. Aggregation can be avoided with a capping agent. ...
Au-Ag nanoalloys have been synthesized using the photochemical reduction method by femtosecond laser from dissolving of potassium gold (III) chloride (KAuCl 4 ) and silver nitrate (AgNO 3 ) added into a quartz cuvette in various volume ratios with a total volume of 3 ml. The samples were then called Au x Ag y , where x and y were the volume fraction for Au and Ag ions, respectively. The samples were irradiated for 15 minutes of irradiation time and characterized by UV-Vis spectrophotometry to observe the absorption spectra in 300-800 nm range and determine the wavelength at which the Localized Surface Plasmon Resonance (LSPR) peak was observed. The process occurred in a water-only medium, in water medium added with 0.01 wt% polyvinylpyrrolidone (PVP) and in water medium added with 0.1 wt% polyvinylpyrrolidone (PVP). The result showed that LSPR of Au-Ag nanoalloys could be tuned between ∼525 nm for Au and ∼403 nm for Ag in a water-only medium, ∼521 nm for Au and ∼412 for Ag in water medium added with 0.01 wt% PVP and ∼522 nm for Au and ∼419 nm for Ag in water medium added with 0.1 wt% PVP.
... In general, nanoparticles are unstable and tend to agglomerate because they are attracted to each other under the influence of van der Waals attractive forces at short inter-particle distances. Thus, there must be a stabilization mechanism in which the nanoparticles cannot attract each other, hence the increase in the stability [11]. Aggregation in nanoparticles is described by Derjaguin-Landau-Verwey-Overbeak (DLVO) theory. ...
Van der Waals attraction between nanoparticles will create aggregation, therefore, adding a capping agent is needed to stabilize the nanoparticles. We have synthesized Au50Ag50 nanoalloys from a mixture of silver and gold metal ions using a femtosecond laser irradiated for 5, 10, and 15 minutes. The process occurred in a water-only medium and in a water medium added with 0.01 wt% polyvinylpyrrolidone (PVP). Only Au50Ag50 with 5 minutes irradiation times that was characterized by TEM. From TEM result, PVP was proven to generate stabilization of the nanoparticles. It was confirmed that the nanoparticles in Au-Ag nanoalloys with PVP are more disperse than the Au-Ag nanoalloys without PVP. From the result, the particle size of Au-Ag nanoalloys without PVP is 10.72 nm, and 7.94 nm with PVP. This indicates that not only reducing the van der Waals attractive forces and stabilizing the nanoparticles, PVP can also reduce the particle size.
... zeta potential measurements, of the studied system provide additional information about its stability [39]. Moreover, at the current state of knowledge the most specialized method in the determination of the colloidal stability is the turbidimetric method [40]. ...
The aim of this paper was to analyze stability, adsorption and the electrokinetic properties of suspensions containing chitosan and silica. Chitosan (Ch), the second most abundant natural polysaccharide, biodegradable and relatively cheap can be very good alternative for artificial polymers used in the stabilization of metal oxide suspensions. The results obtained from spectrophotometric and turbidimetric stability measurements proved that the higher concentrations of chitosan the more stabile the silica suspensions. The mechanism of the stabilization is the electrosteric one because the studied polymer not only adsorb on the silica surface but also possesses amino groups creating additional charge barrier preventing from flocculation. The adsorption of chitosan increases also with the increase of pH of the solution. However, the protonation of this polymer is the highest in pH = 5–6.3 and as the consequence in the above mentioned pH stabilization of the silica suspensions is the best. There is no significant influence of chitosan molecular weight on stability of studied suspensions when concentration of the polymer is relatively low (60 ppm–120 ppm). However, for higher concentrations of chitosan (200 ppm–800 ppm) stability increases with the increase of its molecular weight as well as the adsorption of this polymer on the silica surface. The additional information about stability and the structure of the adsorption layer was obtained from the zeta potential measurements. The presented results can find practical applications connected with functionalized materials especially in medicine, pharmacy, cosmetics and agriculture.
... The electrostatic stabilization is the consequence of the electrostatic repulsion forces. If the particles suspended in the liquid medium possess the same electrostatic charge on its surface they do not attract each other which results in the stability increase [8]. However, this type of stability applies only to the systems in which the range of the electrostatic repulsion is higher than that of the attractive forces and to those containing small particles. ...
... Regarding the situation in which the solid particles covered by the polymer or surfactant attract each other, aggregation and flocculation is observed. To sum up, the addition of surface active agents or macromolecules can cause either stabilization or flocculation of the described systems [8][9]. This is why methods that allow to study the stability of colloidal systems are very important. ...
... Although the addition of the macromolecule to the system might induce the stabilization increase, it might cause destabilization as well. The opposite of the stabilization process is the flocculation, which occurs when the sum of attraction forces are stronger than the repulsion ones [8]. Two main types of the flocculation caused by the polymer can be described. ...
p>The stability of colloidal systems is very important in numerous already existing and new formulations. In most cases if such systems are not characterized by an appropriate stability they can not find any useful applications. The opposite process to the stabilization is the flocculation. Generally, it is undesirable. However, in a few cases the flocculation is very useful, for example in the wastewater treatment. That is why the methods used to determine stabilizing-flocculating properties of the colloidal systems are of significant importance.
The paper describes types of stability and flocculation as well as the factors influencing those processes, e.g. the addition of polymers or surfactants. The methods presented in this paper are UV-VIS spectrophotometry, turbidimetry, zeta potential and density measurements.</p
... Notwithstanding, the addition of polymer can cause not only steric or depletion stabilization of the system but also bridging or depletion flocculation depending on the polymer concentration, its molecular weight and its charge. Recently it has been observed that mixtures of polymers and surfactants can be much more effective than pure solutions of high molecular weight substances (Grządka, 2014;Grządka, Wiśniewska, Gun'ko, & Zarko, 2015;Grządka, 2015). It was proved that in the systems where the presence of surfactant increases, the amount of polysaccharide adsorption, the addition of the surface active agent also increases stability of the polysaccharide/metal oxide dispersed suspensions. ...
The influence of ionic (CTAB; SDS) and non-ionic (TX-100; TX-165 and TX-405) surfactants as well as pH of the solution on the stability, adsorption and electrokinetic properties of the alginic acid (AA)/alumina (Al2O3) suspensions was studied. The results obtained using the spectrophotometric method show that the addition of ionic surfactants is an effective way to obtain stable AA/Al2O3 suspensions whereas the changes in pH are not sufficient. Surface tension measurements together with the adsorption data show that the macromolecules of alginic acid are able to form complexes with CTAB, however, they compete for the adsorption centers on the metal oxide surface with SDS. Non-ionic surfactants do not affect alginic acid adsorption. The electrokinetic measurements (surface charge density and zeta potential measurements) prove that adsorption of alginic acid on Al2O3 with or without surfactants changes the structure or the compact and diffused parts of the electric double layer. It should be emphasized that the alginic acid/surfactant/alumina system has not been studied before which confines its possible applications in the fields of functionalized materials.
... Guar gum, a natural biodegradable polysaccharide consisting of polymannan backbone with galactose side groups, has wide applications in different industrial sectors (Grzadka 2013(Grzadka , 2014. Previous study indicated that guar could effectively trap and retain water molecules within the matrix (Rosiaux et al. 2013). ...
The gas barrier and mechanical properties are crucial parameters for packaging materials, and they are highly correlated to the molecular interactions in the polymer matrix. To improve these properties of TEMPO-oxidized cellulose nanofibers (TOCNs) composite films, we studied the effect using hydroxypropyl guar (HPG) or carboxymethyl guar (CMG) in the preparation of TOCN composite films, which were made by following the solution-casting method. The subsequent film characterizations were carried out by UV–Vis spectra, scanning electron microscopy, oxygen and water vapor permeability measurements, tensile and thermogravimetric analyses. SEM results showed that CMG-based films had denser structures than their HPG counterparts. Moreover, the improved hydrogen bonding of the CMG-based films was partially responsible for the improved gas barrier performance, tensile strength and thermal stability. These results support the conclusion that CMG had advantages over HPG when used in the preparation of TOCNs packaging composite films.
