Zinc Borate Research Articles

Effect of silane coupling agent on mechanical properties, flame retardancy, and ceramifiable behavior of ceramifiable flame‐retardant silicone rubber composite

AbstractIn order to improve the dispersibility of inorganic fillers and enhance its ceramifiable flame‐retardant efficiency, the ceramifiable flame‐retardant silicone rubber composites were prepared using glass powder, zinc borate, ammonium polyphosphate, mica powder, platinum catalyst as ceramifiable flame‐retardant agent, and various silane coupling agents as interfacial modifier. The micromorphology, mechanical properties, flame retardancy, thermal stability, and combustion behavior of ceramifiable flame‐retardant silicone rubber composites, as well as the flexural strength of the corresponding ceramics generated after pyrolysis of the composites were examined. The results reveal that the inclusion of silane coupling agents improves the dispersibility of ceramifiable flame‐retardant agents substantially. The mechanical properties, flame retardancy, thermal stability, and combustion behavior of ceramifiable flame‐retardant silicone rubber composites are all improved. When compared to a composite without a silane coupling agent, the tensile strength of the composite can be improved by up to 1.9 times. Only 0.5phr silane coupling agent is required to raise the vertical combustion rating from V‐1 to V‐0, and the composite with 3 phr KH570 has a LOI value of 38.6. Meanwhile, the heat release rate of the composite is reduced to a certain extent, and the time to ignition and residue are dramatically enhanced after the addition of silane coupling agent in the cone calorimetry test. Moreover, flexural strength of the corresponding ceramics generated after pyrolysis of the composites rapidly increases with increasing silane coupling agent content, which can reach to 24.7 MPa with addition of 3 phr KH570.

Boosting Flame Retardancy of Polypropylene/Calcium Carbonate Composites with Inorganic Flame Retardants.

This study investigates the effects of inorganic flame retardants, zinc borate, and magnesium hydroxide, on the thermal, morphological, flame retardancy, and mechanical properties of polypropylene (PP)/calcium carbonate composites for potential construction industry applications. Polypropylene/calcium carbonate (50 wt.%) composites containing 5 and 10 wt.% flame retardants were prepared using a batch mixer, followed by compression moulding. The results demonstrated enhanced thermal stability, with the highest char residue reaching 47.2% for polypropylene/calcium carbonate/zinc borate (10 wt.%)/magnesium hydroxide (10 wt.%) composite, a notably strong outcome. Additionally, the composite exhibited an elevated limited oxygen index (LOI) of 29.4%, indicating a synergistic effect between zinc borate and magnesium hydroxide. The proposed flame retardancy mechanism suggests that the flammability performance is driven by the interaction between the flame retardants within the polypropylene/calcium carbonate matrix. Magnesium hydroxide contributes to smoke suppression by releasing water, while zinc borate forms a protective glassy foam that covers the burning surface, promoting char formation and acting as a physical barrier to heat transmission and fire spread. Scanning electron microscopy confirmed good dispersion of the additives alongside calcium carbonate within the polymer matrix. Despite the addition of up to 10 wt.% flame retardants, the composites maintained high-notched impact strength.

High-resolution indirect detection of spin-3/2 quadrupolar nuclei in solids using multiple-quantum-filtered through-space D-HMQC experiments

Through-space heteronuclear correlation experiments under magic-angle spinning (MAS) conditions can provide unique insights into inter-atomic proximities. In particular, it has been shown that experiments based on two consecutive coherence transfers, 1H → I → 1H, like D-HMQC (dipolar-mediated heteronuclear multiple-quantum correlation), are usually more sensitive for the indirect detection via protons of spin-3/2 quadrupolar nuclei with low gyromagnetic ratio. Nevertheless, the resolution is often decreased by the second-order quadrupolar broadening along the indirect dimension. To circumvent this issue, we incorporate an MQMAS (multiple-quantum MAS) quadrupolar filter into the t1 evolution period of the D-HMQC sequence, which results in a novel pulse sequence called D-HMQC-MQ. The triple-quantum coherences evolving during this filter are excited and reconverted using cosine-modulated long-pulses synchronized with the sample rotation to avoid spinning sidebands in the indirect dimension. The desired coherence transfer pathways during this sequence are selected using two nested cogwheel phase cycles with 56 steps. This high-resolution heteronuclear correlation technique is demonstrated experimentally for the indirect detection via 1H of spin-3/2 isotopes, such as 11B, 23Na and 35Cl, in zinc borate hydrate, NaH2PO4 and l-histidine hydrochloride, respectively. We show that this experiment can be applied at high magnetic fields up to 28.2 T for protons subject to chemical shift anisotropies larger than 20 ppm, provided the MAS frequency is sufficiently stable since the D-HMQC-MQ experiment, like the parent D-HMQC, is sensitive to MAS fluctuations, which can produce t1-noise.

Dendrite-free zinc metal anode for long-life zinc-ion batteries enabled by an artificial hydrophobic-zincophilic coating

Considering the desired energy density, safety and cost-effectiveness, rechargeable zinc-ion batteries (ZIBs) are regarded as one of the most promising energy storage units in next-generation energy systems. Nonetheless, the service life of the current ZIBs is significantly limited by rampant dendrite growth and severe parasitic reactions occurring on the anode side. To overcome these issues caused by poor interfacial ionic conduction and water erosion, we have developed a facile strategy to fabricate a uniform zinc borate layer at the zinc anode/electrolyte interface (ZnBO). Such protective layer integrates superhydrophobic-zincopholic properties, which can effectively eliminate the direct contact of water molecules on the anode, and homogenize the interfacial ionic transfer, thereby enhancing the cyclic stability of the zinc plating/stripping. As a result, the as-prepared ZnBO-coated anode exhibits extended lifespan of 1200 h at 1 mA cm−2 and demonstrates remarkable durability of 570 h at 20 mA cm−2 in Zn||Zn symmetric cells. Additionally, when coupled to an NH4V4O10 (NVO) cathode, it also delivers a superior cyclability (203.5 mAh/g after 2000 cycles at 5 A/g, 89.3 % capacity retention) in coin full cells and a feasible capacity of 2.5 mAh at 1 A/g after 200 cycles in pouch full cells. This work offers a unique perspective on integrating hydrophobicity and zincophilicity at the anode/electrolyte interface through an artificial layer, thereby enhancing the cycle lifespan of ZIBs.

Spectroscopic investigation of co-formers on Dy3+ ions activated Barium comprised zinc borate glasses for enhancing the solid-state laser applications

The purpose of the existing research is to analyze the luminescence behavior on a set of different co-formers involved Dy3+ ions activated Barium comprised zinc borate glasses fabricated through the utilization of usual melt quenching technique with a glass composition of 64B2O3+20ZnF2+15BaO+1Dy2O3 & 44B2O3+20A+20ZnF2+15BaO+1Dy2O3 (where A = 0, P2O5, TeO2, Bi2O3). Their structural, optical, luminescence and decay behavior were scrutinized by several respective characterization techniques. Some of the physical properties were calculated by utilizing the corresponding formulae. Besides, the bonding parameter and oscillator strength estimation alongside Judd-Ofelt parameter are also computed to find out the radiative properties from luminescence spectra. From these analyses, ionic nature of the glass network was confirmed. The spectroscopic intensity parameter follows the tendency Ω2>Ω6>Ω4. This higher value of Ω2 is owing to the larger oscillator strength value and signalizing that Dy3+ ions are completely doped into the glass network. Among all the as- quenched samples, BZfBaT:Dy glass possesses high stimulated emission cross-section and holds high optical gain width value which implies that the glass is a perfect candidate intended for laser utilization. By utilizing its emission spectra, the colour chromaticity coordinates (x, y), colour purity, colour correlated temperature (CCT), and Y/B intensity ratio were investigated by means of CIE 1931 diagram and confirmed the light emitting capability. Decay curve displays well-fitting with the exponential fit and the efficiency (ɳ) for the BZfBaP:Dy glass is found to be 61 % and possesses high optical gain signalizing that the material is a perfect choice for optoelectronic applications.

Mechanochemistry induced mixed ionic/electronic conductive interphase enabling dendrite-free lithium metal anodes

High-energy-density lithium metal batteries have shown promising applications in drones and electrical vehicles. However, the growth of lithium dendrites and the formation of unstable solid electrolyte interphase (SEI) become the main factors restricting their development. In this study, dendrite-free lithium metal anodes (ZB@Li) were developed with ionic/electronic conductive interface layers by a solvent-free mechanochemical method. By rubbing zinc borate (ZB) powder on lithium foil, a mixed interface layer is formed with the generation of lithium borate phase and the Li–Zn alloy phase. The lithium borate phase provides a low diffusion energy barrier and high ionic conductivity for sufficient potential gradient to induce rapid deposition of ions on the interface layer. The Li–Zn alloy phase owns the lithiophilic characteristic and a high electronic conductivity. The combination of the two phases provides mixed ions/electrons paths with enhanced transport kinetics and realize uniform and planar deposition of lithium. As a result, the ZB@Li symmetrical cell exhibits a prolonged cycling performance of over 4,200 h and the ZB@Li||LFP (LFP= lithium iron phosphate [LiFePO4]) full cell shows a long cycle life for more than 500 cycles at 2 C with a high capacity retention rate of 84.6% at a high loading mass of 10 mg/cm2.

Towards the Reuse of Fire Retarded Polyamide 12 for Laser Sintering.

The control of powder aging during Selective Laser Sintering (SLS) processing is one of the challenges to be overcome for the implementation of this technique in serial production. Aging phenomena, because of the elevated temperatures and long processing times, need to be considered when a fraction of the polymer powders present in the build chamber and not used to manufacture the parts are reused at various times. The aim of this study was to investigate the influence of successive reuse of blends of pure Polyamide 12 and its blends with two types of flame retardants (FR): ammonium polyphosphate (APP) and zinc borate (ZB). The composition of the blends was 70/30 (wt/wt) PA 12/FR. Four successive processing stages have been carried out by collecting the remaining powder blend each time. The powders were re-used using the same processing parameters after sieving. DSC measurements showed that the incorporation of FRs entailed a reduction in the processing window up to 4 °C; nevertheless, no further reduction was noted after aging. The TGA curves of aged blends of powders were also similar for pure PA 12 and PA 12 with FR. In addition, initial and reused powders presented a higher degree of crystallinity than the specimens processed from the powders. The heterogeneous character of the PA 12 after LS processing or reprocessing was shown through Pyrolysis Combustion Flow Calorimetry (PCFC) and cone calorimeter (CC) tests. FTIR analysis also showed that post-condensation reactions have occurred. The mode of action of the flame retardants was clearly seen on HRR curves at both tests. The first reuses of PA 12 powders entailed a significant reduction in time to ignition at the cone calorimeter (150 for the initial material to around 90 s for the reused material), indicating the formation of short polymer chains. Only in the case of zinc borate was it noticed that re-used powder was detrimental to the fire performance because of a strong increase in the value of pHRR (between 163 and 220 kW/m2 for reused material instead of 125 kW/m2 for the initial one).

Effect of partial replacement of antimony trioxide with zinc borate and stannic oxide on the flame retardancy of flexible PVC films

AbstractReplacing antimony trioxide (Sb2O3) with an environmentally friendly alternative is of great scientific and commercial value for studying the flame retardant properties of flexible PVC (fPVC) films in automotive interior materials. This study develops flame retardant fPVC films with reduced Sb2O3 content by introducing stannic oxide (SnO2) and zinc borate (ZB). The results indicate that the fPVC film with ZB partially replacing Sb2O3 exhibits superior flame retardancy and smoke suppression compared to the product containing SnO2. The peak heat release rate (PHRR), total heat release (THR), and total smoke release (TSR) of 2ZB/2Sb2O3 fPVC film are reduced by 32.1%, 27.5%, and 22.1%, respectively, compared to that of 4Sb2O3 contained fPVC film. The increase in flame retardancy is attributed to the presence of ZB, which compensates for the deficiency of char formation ability of Sb2O3 in the condensed phase. The PHRR and THR of 2SnO2/2Sb2O3 fPVC film decrease by 27% and 12.5%, respectively, compared to that of 4Sb2O3 fPVC film, while the TSR increases by 16.5%. This study develops a straightforward approach to creating a flame retardant fPVC film that is suitable for the latest industrial application in automotive interior materials.

Recovery of boron and zinc from wastewater via electrodialytic metathesis

With the development of industrial civilization, large amounts of wastewater containing boron and zinc are being produced. Such wastewater poses a great threat to human health if discharged without treatment. In this study, an integrated technology of electrodialytic metathesis (EDM) and a hydrothermal process was utilized to recover boron and zinc from wastewater in the form of zinc borate (Zn2B6O11·3H2O). Experimental results showed that electrolyte concentration, current density, and initial boron and zinc concentration clearly affected the recovery ratios for B4O72− and Zn2+ and their corresponding specific energy consumption and current efficiencies. Under the optimal experimental conditions (an electrolyte concentration of 1.0 mol/L in the recycling compartment in the experimental setup, a current density of 15 mA/cm2, initial ZnSO4 and Na2B4O7 concentrations of 0.1 mol/L, and a flow rate of 20 mL/min), the recovery ratio, specific energy consumption, and current efficiency were 85.6 %, 6.5 kW·h/mol, and 12.3 %, respectively, for recovering B4O72− and 80.6 %, 1.7 kW·h/mol, and 45.7 %, respectively, for recovering Zn2+. When one recovery compartment was employed, the current efficiencies for recovering B4O72− and Zn2+ were 12.3 % and 45.7 %, respectively, and these values were 11.4 % and 43.8 %, respectively, when two recovery compartment were used. After B4O72− and Zn2+ concentrated by EDM were treated via a hydrothermal process, a white precipitate was produced. The results of X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analyses showed that this precipitate exhibited physicochemical properties similar to those of commercial Zn2B6O11·3H2O. Thus, the integrated technology can be regarded as an effective method for recovering boron and zinc from wastewater.

Microwave melt-quenching technique to synthesize of CuO-doped B2O3–ZnO–Na2O–Sm2O3 scintillating glasses

The new series of CuO-doped samarium sodium zinc borate (SNZB) glasses, with the composition (59.5-x)B2O3:30ZnO:10Na2O:0.5Sm2O3 (x = 0.00–0.10 mol%), were prepared using the microwave melt-quenching technique. These glasses were characterized through XRD, absorption, excitation, photoluminescence (PL), and X-ray luminescence (RL) spectral measurements. The optical absorption analysis revealed a significant increase in the visible Cu2+ absorption band at approximately 770 nm with the addition of CuO at concentrations ranging from 0.00 to 0.10 mol%. From the absorption spectra of SNZBCu-0.00, the Judd-Ofelt (J-O) intensity parameters (Ω2, Ω4, Ω6) were determined. Under 402 nm excitation, the PL spectra exhibited a bright reddish-orange emission at 600 nm. The decay spectral profiles of the 4G5/2 → 6H7/2 (600 nm) luminescence transition were used to measure experimental lifetimes (τg).

Effect of Hold Time on Electrical Properties of Lithium Zinc Borate Glass Ceramics for Energy Storage Applications

Effect of Hold Time on Electrical Properties of Lithium Zinc Borate Glass Ceramics for Energy Storage Applications

Production and characterization of flame-retardant poly (butylene terephthalate) composites containing boron compounds

ABSTRACT Within the scope of this work, flame retardant polybutylene terephthalate (PBT) was produced using boron compounds, namely, anhydrous borax (BX), colemanite (C), and zinc borate (ZnB) in three different concentrations of 40, 50, and 60 wt%. The thermal, flame retardant, and tensile properties of PBT composites were systematically investigated using thermogravimetric analysis (TGA), limiting oxygen index (LOI), vertical UL 94 test (UL-94V), mass loss calorimeter (MLC), and tensile tests. The thermal stability of PBT slightly enhanced with the use of BX, whereas the use of C and ZnB reduced the thermal stability. Improvement in LOI value, a reduction in peak heat release rate (pHRR), and total heat release (THR) values were observed with the use of all boron compounds. The improvement in UL-94V rating was observed only with the use C. The addition of all boron compounds deteriorates the tensile strength of the composites. In brief, the highest flame retardant performance with V0 rating (UL-94 V), 33.5% (LOI), and 48 Kw·m−2 (pHRR) was achieved with the use of C.

Effect of Gd3+ ion on silver zinc borate glasses

The conventional melt quenching technique approach has been used to create glasses with the composition of ZnO-B2O3-Gd2O3-Ag2O.Using the X-ray diffraction technique, the synthesized glasses have been characterized. Using the Archimedes method, the density and molar volume were calculated. To record the absorption spectra, a UV–visible spectrometer was employed, the energy band gap has been evaluated using Tauc's plots. The variation of band gap energies related to Gd2O3 concentration has been discussed. FTIR spectra are examined to determine the sample's structure and functional group. When the Gd3+ ion is added to the doped glass, the photo luminescence spectra produces a consistent orange-red emission, as evidenced by the colour coordinates obtained from the CIE diagram.

The effect of zinc substitution on the optical properties of Sm3+ doped zinc borate glasses

Zinc borate glasses are a relatively well known glass type that can be produced at comparably low temperatures. Variations in both the type and concentration of network modifier atoms induce structural alterations within the glass matrix. If doped with optically active dopants, e.g. rare earth ions, compositional changes also affect the local surrounding of the dopants and consequently their optical properties such as emission peak shape and peak ratio. To investigate the effect of different low field strength network modifier ions in zinc borate glasses two glass series were prepared using the melt quench technique; Sm3+ was used as dopant ion: 50B2O3, xK2O, (49-x)ZnO, 1Sm2O3 (x = 5,10,15, …, 30 mol%) and 50B2O3, 30MO, 19ZnO, 1Sm2O3 (M = Ca, Sr and Ba). It is found that the substitution of ZnO for K2O notably enhances the intensity of the red Sm3+emission. Based on the literature this effect is attributed to a change in symmetry at the rare earth position. Additionally, the effect of network modifier concentrations and the different network modifier types on the Sm3+ absorption spectra is examined, discussed and compared to literature data. Furthermore, the glasses are characterized according to their density, refractive index, molar volume, and oxygen packing density.

Effect of the Addition of WO3 on the Structure and Luminescent Properties of ZnO-B2O3:Eu3+ Glass.

Glasses with the compositions in mol % of 50ZnO:(50 - x)B2O3:0.5Eu2O3:xWO3, x = 0, 1, 3, 5 and 10 were obtained by applying the melt-quenching method and investigated by Raman spectroscopy, DSC analysis and photoluminescence (PL) spectroscopy. Raman spectra revealed that tungstate ions incorporate into the base zinc borate glass as tetrahedral [WO4]2- groups, and octahedral [WØ4O2]2- species with four bridging and two non-bridging oxygen atoms. There are also metaborate, [BØ2O]- and pyroborate units, [B2O5]4-, in the glass networks. The glasses are characterized by good transmission in the visible region, at about 80%. Photoluminescence (PL) spectra evidenced that WO3 is an appropriate constituent for the modification of zinc borate glass structure and for enhancing the Eu3+ luminescent intensity. The most intense luminescence peak observed, at 612 nm, suggests that the glasses are potential materials for red emission.

Effect of titanium ion doping on γ-ray shielding, structure and dielectric characteristics of glasses made of barium zinc borate

Effect of titanium ion doping on γ-ray shielding, structure and dielectric characteristics of glasses made of barium zinc borate

Improving the flame retardancy and smoke suppression of flexible PVC by incorporating zinc borate‐modified diantimony trioxide

AbstractThe properties and structure of flexible PVC by incorporating zinc borate (ZB)‐modified diantimony trioxide (Sb2O3) were investigated. The results of flame retardancy and smoke suppression testing indicate that there was an obvious maximum Limited oxygen index (LOI) value of PVC/20 wt.% ZB–Sb2O3 composites reached 37.5% and passed the UL 94 V‐0 rating. An obvious synergistic effect between ZB and Sb2O3 was observed by LOI, SDR, and TG. Moreover, remarkable decreases in the smoke density were observed when ZB–Sb2O3 was incorporated into PVC. In addition, the tensile strength and elongation at break of PVC/ZB–Sb2O3 composites was higher than PVC/Sb2O3 composites, and this ameliorative effect was mainly arising from the ZB–Sb2O3 nanoparticles, which reduced the degree of fatal defects on PVC. The addition of ZB and Sb2O3 greatly increased the amount of residual char and apparently improved the mechanical properties of PVC composites. According to scanning electron microscopy photographs of residual char, after thermal decomposition, there were many fragments linked to the condensed phase and the compact char layer. Fourier transform infrared spectroscopy shows the residues char was composed of benzene ring, the flame retardants occurred and the condensed phase with significant interactions.

The effect of bismuth oxide substitution on physio-elastic properties of new formulation zinc borate glass system

The effect of bismuth oxide substitution on physio-elastic properties of new formulation zinc borate glass system

Optical and gamma ray shielding properties of lead magnesium zinc borate (PMZB) glasses

As the concentration of PbO in PMZB glasses is increased, the result is an elevated density and a reduced molar volume. As the percentage of PbO in the sample grows, the absorption peak in the optical spectrum has moved towards longer wavelength side. Creating non-bridging oxygens leads to a reduced gap in the band energy. When the content of Pb rises, so do the dielectric and optical dielectric constant values and the refractive index, suggesting an enhanced influence of non-bridging oxygens. The non-metallic character is confirmed by the metallization values, which vary from 0.382 to 0.362. Molar refractivity decreases with PbO content. This study conducted an evaluation of the radiation shielding characteristics in the 0.122–1.46 MeV range. The linear attenuation coefficient varied between 11.073 and 15.161 cm−1 at 0.122 MeV. The PMZBX glasses have lesser absorbing capabilities for high energy photons because of their greater penetration abilities. Thus, the PMZB4 glass, which has the greatest PbO content, shows the most promise out of the tested glasses.

Effect of Sn on Physical and Optical Properties of Lithium Zinc Borate Glasses

22.5 Li2O3-(20-x) ZnO-57.5B2O3 – xSnCl2 (x = 0, 0.5. 1) glasses were synthesized using the conventional melt quench technique. Glass composition with larger concentration of lithium oxide exhibits excellent transport properties. Introducing intermediate element like zinc into the matrix will lead towards slight modification in structure by not varying much in its intrinsic properties. Thus, incorporation of Sn as dopant into the matrix has tailored the physical and optical properties of glasses. In this study, it is interesting to note that, the density of the glass has reduced for 0.5 mol % SnCl2 in the matrix and on the contrary, the density of glass was found to be increased for the SnCl2 with 1 mol % concentration. It indicates that, there could be a possibility of slight modification in the structure of glasses which eventually leads towards tuning of the optical bandgap due to existence of Sn.