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Hydrogels with porous networks have received considerable attention in smart pesticide delivery due to their inherent versatility. In this study, acaricide cyetpyrafen (CPF)-loaded borax (BO) cross-linked hydroxypropyl guar gum (HPG) (CPF@BO- co -HPG, CBG) hydrogels were prepared by cross-linking and pesticide loading simultaneously. The flowable CBG hydrogels with 3D porous network structures had better wetting and spreading ability on Citrus reticulata Blanco leaves and a hydrophobic interface. The nonflowable CBG hydrogels had pH- and temperature-responsive release properties. Meanwhile, the acaricidal efficacy of CBG against Panonychus citri (McGregor) at both 24 and 48 h was significantly higher than those of CPF-loaded BO-free HPG hydrogels. Furthermore, CBG had a nutritional function for cotton growth and environmental safety for zebrafish. This research developed a BO cross-linked HPG hydrogel as a smart pesticide delivery vehicle and crop nutrient replenishment, which can be widely applied in sustainable agriculture.

The solubility and nucleation ofborax decahydrate in the presenceof Cl–and SO42–ionshave been studied by two different methods: polythermal crystallizationand isothermal crystallization. The results revealed that both anionshad a salt-in effect on the solubility. A noticeable widening of themetastable zone was observed after the addition of the two anion impurities.For the isothermal crystallization, two different nucleation mechanismswere obtained. When the supersaturation ratio S>1.3, the nucleation appears to be homogeneous, whereas at the supersaturationratio S< 1.25, heterogeneous nucleation predominates.From the prolonged induction period in the presence of the two anions,we conclude that the nucleation of borax decahydrate was suppressedafter the addition of impurities. The values of the interfacial energyγ calculated by isothermal method are lower than those obtainedby polythermal method due to the underestimated values of ln S. [ABSTRACT FROM AUTHOR]

Thesolubility and the metastable zone width of sodium tetraboratedecahydrate in solutions containing lithium chloride have been measuredat temperature a range of (20 to 35) °C. It is found that thelithium impurity has a salt-in effect on the solubility of sodiumtetraborate decahydrate. The metastable zone width broadens with anincrease of the impurity concentrations. This increase can be attributedto the absorption mechanism on the crystal surface. The apparent nucleationorder of sodium tetraborate decahydrate with and without impuritywas calculated by a modified regression method. The results show thatthe addition of lithium impurity has no great effect on the apparentnucleation order of sodium tetraborate decahydrate. [ABSTRACT FROM AUTHOR]

The solubility and ultra solubility of borax decahydrateboth inpure and impure solutions have been determined in the temperaturerange from (0 to 30) °C by means of the conventional polythermalmethod using the laser technique. The metastable zone width and theapparent nucleation order of borax were calculated. The effects andthe action mechanism of KCl on metastable zone property of borax werestudied. It was found that the presence of KCl made an increase inthe solubility and a decrease in the metastable zones of borax. However,the trends in the changes of metastable zone width at low impurityconcentrations were different from high concentrations because ofthe adsorption equilibria on the crystals. [ABSTRACT FROM AUTHOR]

A gel-like, high-viscosity polymeric dispersion (HVPD) based on cross-linked borate, partially hydrolyzed poly(vinyl acetate) (xPVAc, where xis the percent hydrolysis) is described. Unlike hydro-HVPDs prepared from poly(vinyl alcohol) (PVA) and borate, the liquid portion of these materials can be composed of up to 75% of an organic cosolvent because of the influence of residual acetate groups on the polymer backbone. The effects of the degree of hydrolysis, molecular weight, polymer and cross-linker concentrations, and type and amount of organic cosolvent on the rheological and structural properties of the materials are investigated. The stability of the systems is explored through rheological and melting-range studies. 11B NMR and small-angle neutron scattering (SANS) are used to probe the structure of the dispersions. The addition of an organic liquid to the xPVAc-borate HVPDs results in a drastic increase in the number of cross-linked borate species as well as the agglomeration of the polymer into bundles. These effects result in an increase in the relaxation time and thermal stability of the networks. The ability to make xPVAc-borate HVPDs with very large amounts of and rather different organic liquids, with very different rheological properties that can be controlled easily, opens new possibilities for applications of PVAc-based dispersions. [ABSTRACT FROM AUTHOR]

Guar gum is a galactomannan that assumes a very flexible conformation in solution, while Scleroglucan is a very rigid polysaccharide that dissolves in water as triple helices. Both polymers can form gels in the presence of borax. Despite their structural differences, the freeze-dried gel systems of both polymers, when compressed to form tablets, show a peculiar anisotropic swelling in water that reflects an amazing similarity in terms of their molecular properies. In this paper the behavior of the Guar/borax gel is compared with that of Scleroglucan/borax. The macroscopic properties of the two systems were characterized in terms of rheological measurements. Atomic force microscopy images and molecular dynamics simulation allowed to evaluate, at molecular level, the effect of borax addition to the Guar polymer. Both experiments show that an increasing of the polymer rigidity is produced by borax. The role played by galactose in the side chain was also discussed. [ABSTRACT FROM AUTHOR]

The overall growth kinetics of ammonium pentaborate, borax decahydrate, and boric acid crystals in pure solutions were analyzed using a two-step mass transfer model. Four different linear expressions of the two-step mass transfer model (TSM), which include the widely used expressions of Sobczak and Karpinski, were discussed. The influence of linearization for an assumed second-order reaction kinetics on the mass transfer and reaction steps was studied for various crystallization systems with overall growth kinetic order ranging from 1 to ≥2. The overall growth kinetics of ammonium pentaborate and borax decahydrate were used to study the effect of linearization as a function of temperature and seed size. The complexities in using the linearized TSM expression to predict the mechanism of the crystal growth process in pure solutions were discussed. A Type 3 expression of Karpinski that successfully represents the overall crystal growth kinetics was determined to be successful in representing two-step growth of borax decahydrate and ammonium pentaborate crystals. Type 1 and Type 4 expressions were determined to be inappropriate for the studied crystallization systems, because they either poorly fit the growth kinetics or produce kinetic parameters without physical meaning. The Sobczak expression well-represents the overall crystal growth kinetics of second order or more, and the Karpinski expression was determined to be successful in representing the overall crystal growth kinetics of order near or equal to unity. [ABSTRACT FROM AUTHOR]

Oxidized alginate (ADA) and oxidized alginate blended with chitosan (ADA-Chit) were prepared in the presence of borax and CaCl 2, and their interactions with an antifolate drug, pyrimethamine (PYR), have been investigated. Tablets with a mean diameter of 1.2 ± 0.06 cm were produced and drug interactions were performed in dimethyl sulfoxide (DMSO) using isothermal titration calorimetry (ITC). From ITC responses, the enthalpy changes of interaction PYR/materials, Δ intH, have been determined and were found to be −11.73 ± 0.517 kJ mol −1for ADA and −4.86 ± 0.156 kJ mol −1for ADA-Chit. The PYR encapsulation of approximately 75% was achieved for both materials, as measured by UV spectrometer. [ABSTRACT FROM AUTHOR]

An additive is not exclusively retardant or promoter for a crystallization system. The kinetic studies of calcium sulfate dihydrate (CSD) crystal growth demonstrated that borax played dual roles in the reaction, which accelerated CSD formations at the low concentration levels but inhibited the crystal growth at the high ones. In situ atomic force microscopy studies revealed that borax modulated the CSD crystallization via two different pathways:  promoted the secondary nucleation to increase the step density on the growing crystal faces but simultaneously retarded the spread of these growth steps by the Langmuir adsorption. These two contradictory factors were incorporated in the crystallization, and their balance was regulated by the borax concentration. Both the macroscopic and microscopic experimental data nicely displayed the crystallization model of birth and spread that was able to account for the behaviors of borax in CSD formations. [ABSTRACT FROM AUTHOR]

Investigates the effect of adding borax and boric acids on the nucleobase orientation and recognition behavior of novel mono- and oligomeric peptide ribonucleic acids (PRNA). Base orientation of 5'-amino-5'-deoxyuridine and 5'-amino-5'-deoxycytidine; Ability of gamma-PRNA 8-mer to form a tight complex with DNA.

In this work, we prepare guar gum-based supramolecular hydrogel through the formation of borate/didiol bonds. This dynamic and reversible noncovalent borate/didiol interaction is critical for the multifunctional properties of supramolecular hydrogel. The FT-IR and XRD analysis verified the existence of boronate ester interactions between borax and guar gum. Moreover, the viscoelastic and mechanical behaviors of the hydrogels with different guar gum concentrations showed that the storage modulus and compressive stress were highest at guar gum concentration of 2 wt %. Besides, due to the dynamic and reservable properties of boronate ester, these guar gum-based hydrogels had excellent self-healing property, outstanding reformable and injectable capability. In addition, hydrogels also exhibited reversible gel-sol transformations by the application of physicochemical stimuli such as thermal and pH value. The coupling of these multifunctional properties made from low-cost, environment friendly, and readily available materials could have potential applications in many biomedical areas in the future. We expect that this simple strategy of fabricating the self-healing guar gum hydrogels with multistimuli responsive properties may enrich the avenue in the exploration of multifunctional guar gum based hydrogels to expand their potential applications in various fields.

Presents a laboratory information profile of borax. Physical properties; Hazardous characteristics; Symptoms of acute exposure; Storage requirements; Effect of ingestion and prolonged skin contact.