Papers by Keyword: Borax

Abstract: Epoxidized natural rubber (ENR) has attracted significant attention due to its outstanding properties, such as mechanical properties and oil resistance. In particular, the development of self-healing properties without external stimuli in ENR has been an important challenge. In this study, the self-healing ENR composites were successfully developed by incorporating microcrystalline cellulose (MCC) as a reinforcing agent and borax as a dynamic cross-linker. The addition of borax resulted in the formation of dynamic borate-ester bonding and hydrogen bonding, enhancing the mechanical properties and self-healing ability of the composites. Structural analysis confirmed good compatibility between borax and MCC. The borax-grafted MCC reinforced ENR composite with 5 wt% borax achieved significant improvements, with self-healing efficiencies reaching 99% in Young’s modulus, 96% in tensile strength, 84% in elongation at break, and 76% in tensile energy after self-healing time 24 h at room temperature, without external stimuli. These results demonstrated the potential of ENR-based composites for sustainable and self-healing rubber applications.

Abstract: This study focused on the preparation of hydrogels of poly (vinyl alcohol) and cellulose extracted from hemp fibers with the aid of borax as a cross-linking agent. Cellulose extracted from hemp fibers was initially dissolved in a mixed solution of urea and NaOH to obtain a cellulose solution. In the meantime, PVA was also dissolved in the urea and NaOH. These two solutions were mixed, and various loadings of borax were introduced. Moreover, the effect of borax loadings on equilibrium water content (EWC) and compression properties of the cross-linked hydrogels was investigated. The cross-linked hydrogels showed an EWC of 95.76% and a compression set of 9.71%, compared to those of the physical cross-linked hydrogels which had an EWC of 92.40% and a compression set of 29.96%. It was found that the chemically crosslinked hydrogels exhibited greater stability compared with physical ones owing to the stronger interaction induced by borax. Therefore, The PVA/cellulose hydrogels cross-linked with borax hold potential in various applications such as wound dressing, wastewater treatment, and agricultural fields.

Abstract: Hydrogels are polymers with soft and high-water absorption characteristics similar to biological tissues, leading to several potential applications, such as artificial organs, drug delivery, tissue engineering, and strain sensor. Interestingly, hydrogels can be designed to heal themselves after being damaged. In this research, hydrogels with self-healing ability from pectin and polyvinyl alcohol were prepared by simple physical mixing. Borax was used as a crosslinking agent to obtain crosslinked hydrogel structure by the formation of dynamic boron ester bonds. Glycerol was also added to the hydrogels as an anti-freezing agent and a stabilizer. The microstructures, mechanical properties, self-healing ability and swelling properties of the pectin/PVA-borax hydrogels were characterized. The results indicate that the size of microporous structure, modulus, tensile strength, self-healing time, swelling, and equilibrium water content of the pectin/PVA hydrogels increases with the increasing borax contents.

Abstract: Raw pumice samples were modified with nano carbon black, borax, and nano carbon-borax using the sol-gel method by applying surface modification processes, and the changes in the thermal behavior of the surface modification of the raw pumice were studied by characterizing them with FE-SEM, EDX, FT-IR, XRD, BET and TGA-DTA. In the analyses made with FE-SEM, it was observed that the surface and pore structure of the raw pumice changed after the modified process, and in the EDX analysis, it was determined that nano carbon black and borax adhered to the surface of the raw pumice. In the XRD results, no change in the crystal structure of the raw pumice was observed after the modified treatment. TGA-DTA analysis showed that the mass loss of raw pumice (P) was greater than pumice-nano carbon black (PC), pumice-borax (PB), and pumice-borax-nano carbon black (PBC). Accordingly, raw pumice showed a mass loss of approximately 25%, pumice-borax (PB) and pumice-nano carbon black (PC) 0.45%, and pumice-borax-nano carbon black (PBC) nearly 3%. According to the BET analysis results, it was determined that the raw pumice has a surface area of 28.126 m²/g. After the surface modification process, the surface area of the raw pumice was determined as 52.127 m²/g in the pumice-nano carbon black sample, 49.125 m²/g in the pumice-borax sample, and 32.523 m²/g in the pumice-borax-carbon black sample. Considering the data obtained, the best surface properties were showed in pumice-nano carbon black (PC). Research results showed that; the modification process with nano carbon black and borax changed the thermal behavior of raw pumice.

Abstract: The effects of borax on the setting time, compressive strength, bond strength, drying shrinkage and pH value were investigated for potassium magnesium phosphate cement (MKPC). The results show that with the increase of borax dosage, the setting time is gradually extended, both compressive strength and bond strength are greatly decreased, the drying shrinkage rate is increased. Especially high dosage of borax, the extension of setting time is more obvious. Compared with that without borax, when the dosage of borax is 12.5%, setting time can be prolonged by 214.8%.The influence of borax dosage on the time-dependent effect of compressive strength shows that when the dosage of borax is 2.5%~5.0%, compressive strength increases rapidly from 4h to 1d, and increases relatively slowly from 1d to 3d. When borax dosage is less than 2.5% or higher than 5%, the law of time-dependent effect of compressive strength is the opposite. Compared to borax prior to magnesia addition, the pH value of the system is larger and the time of inflection point is advanced when borax and magnesia are mixed together at the same time. The increase of borax dosage can reduce the pH value of the system, and decrease the rising rate of pH value, at the same time the required time when the final pH value is relatively stable is longer.

Abstract: Geopolymer that was made with high CaO content fly ash was found to have higher compressive strength than the low CaO fly ash, using the same mixture composition. This effect could be due to the physico-chemical properties of the fly ash, in respect to its particle size or the chemical composition. Although it was not widely published, the occurrence of flash setting of geopolymer was known to occur when using high CaO content fly ash as the precursor. Geopolymer paste may solidify within minutes after the addition of alkali activators, making it very difficult to cast in big volume. This paper investigate the effect of borax addition to the high calcium fly ash-based geopolymer mixture to reduce the occurrence of flash setting. It was found that the setting time can be extended significantly, with the addition of 5% borax, by mass, of fly ash. The addition of borax also have positive effect on increasing the compressive strength of geopolymer.

Abstract: This work investigated the recycling of fly ash waste and cullet as the raw materials for lightweight bodies produced by heat treatment and using sodium silicate as the binder. Borax was mixed with fly ash and cullet, and put into the block in dimension 10x10x2 cm³. The lightweight materials thus produced were then sintered at temperature of 800 °C. Density, compressive strength and thermal conductivity were determined. Borax showed a positive sintering effect on the porosity of lightweight material during the heat process. The compressive strength of lightweight material diminished with the reduction of density and thermal conductivity. Lightweight material manufactured with borax showed the lower density and thermal conductivity accompanied by the higher compressive strength. The test results indicated that using fly ash and cullet as the raw material with borax could obtain the lightweight material, thus enhancing the possibility of its reuse in a sustainable way.

Abstract: Due to rapid growing of nanotechnology, it is currently being used in many areas including biotechnology, electronics, drug delivery systems, cosmetics, material science and biosensors. Oxidative stress is considered as main cause behind the toxicity of nanoparticles (NPs). Recent reports indicate that boron is effective in protecting cells or organisms against oxidative damages by enhancing antioxidant defense mechanisms. However, protective role of boron compounds in nanotoxicity is not investigated yet. Therefore we assessed the potential protective role of boric acid (BA) and borax (BX) against the toxic responses of nano-Fe₃O₄ particles (IO NPs) in cultured human whole blood cells. Our results showed that IO NPs induced genotoxicity in human lymphocytes demonstrated by sister chromatid exchange (SCE) and 8-hydroxy-2′-deoxyguanosine (8-OH-dG) assays. Again, IO NPs caused decreases of total antioxidant capacity (TAC) and decreases of total oxidative stress (TOS) levels in vitro. Co-application of boric acid and borax (2.5 to 10 ppm) into the cell cultures significantly ameliorated genotoxicity and oxidative stress caused by IO NPs. In a conclusion, this study is the first report revealing that BA and BX significantly protected human blood cells from the toxicity of IO NPs, which is mediated through the generation of oxidative stress and depletion of antioxidant capacity.

Abstract: The influence of magnesium to phosphate weight ratios (M/P ratio), borax content, water to cement ratio (w/c ratio), fly ash, slag on magnesium phosphate cement of drying shrinkage is examined.The results show that the drying shrinkage of magnesium phosphate cementcan be affected at some extent by M/P ratio, w/c ratio,boraxcontent. Both the former two factors and the effects are significant.It was found that the drying shrinkage of magnesium phosphate cement decrease with the increase of M/P ratio,borax content, w/c ratio. If the 10%, 15% offly ashinstead of magnesium phosphate cement was added, drying shrinkage rate decreases with increases of dosage fly ash. When the 15% of magnesium phosphate cement is replaced by fly ash, the shrinkage rate of hydration 20d reachs11.2×10^-5. When the 10% of magnesium phosphate cementis replaced by slag, the drying shrinkage rate reducedto 87.6%.comparing to the bench mark ,the drying shrinkage rate of 20d is only 2.78×10^-5.

Abstract: According to analyze service condition and extent of damage of cordierite bricks used in coke oven, the experiment was prepared by using spodumene powder, cordierite powder and fused silica as main starting materials, borax as the flux. The effect of borax on melting properties and thermal shock resistance of low-temperature glaze used in coke oven cordierite brick was investigated. The results showed that the melting temperature of glaze is close to the theoretical calculation, Seger formula can be equally applied to metallurgical industry. With the amount of borax increasing, the melting temperature of the glaze reduced. When the amount increased to 22%, borax dissolved in the mullite phase, which increased the content of glass phase in glaze. When the temperature is 1000°C, glaze layer formed and spreaded evenly on the surface of cordierite lining bricks and didn’t flowing. After five thermal shock, glazed surface didn’t appear crack, the requirements were achieved that glaze can be generated in the carbonization chamber temperature of coke oven without pre-firing. When the amount of borax continues to increase, the viscosity of glaze decreases, which results in flowing.