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Crystalline silica nanoparticles exhibit superior physical properties to amorphous phase when incorporated in nanocomposites. In this paper, we introduce the crystalline silica nanoparticles–embedded nanocomposites (CSN–nanocomposite) as a high-performance insulation material, and discuss their improved macro/microscopic properties according to the CSN contents. Monodisperse CSN particles (50 nm in size) are produced via facile and cost-effective top-down grinding methods, and their surfaces are modified with organic ligands to endure homogeneous dispersion and chemical crosslinking with epoxy matrix. With the aid of optimal hybridization of the CSN and the matrix, the CSN–nanocomposite exhibits high optical transparency, enhanced mechanical strength, increased thermal conductivity, and improved electrical insulating property.

We report the development of a class-II-type hybrid coating (NS-EP hybrid) composed of surface-modified nanosilica (NS) as the filler and a thermo-curable epoxy polymer (EP) as the matrix. NS is synthesized using a hydrolytic sol-gel process; its hydroxyl surface is rendered cross-linkable using glycidyl ligands to ensure homogeneous dispersion and optimal hybridization with the EP matrix. The NS-EP hybrid shows high optical transparency, enhanced mechanical properties, and improved moisture barrier performance. Further, we discuss the physical properties of the hybrid with respect to the NS content. To study the applicability of the hybrid as a high-performance barrier material in practical applications, an actual OLED device is encapsulated using the hybrid.

We report the facile fabrication of transparent and high-performance moisture barrier material (SC nanocomposite) using surface-modified bentonite clay (SC) as nanofiller and glycidyl silane as a surface-modifier/binder via simple, cost-effective and mass-producible process. SC is synthesised using a base-catalysed sol-gel process; their hydroxyl surfaces are decorated with glycidyl ligands to endure the densely stacked structure and high clay content in the final nanocomposite. The SC nanocomposite barrier exhibits high optical transparency (>90), dense multi-stacked clay structure, and considerably enhanced moisture barrier performance. We discuss the fabrication and physical properties of the SC nanocomposite. To assess the applicability of the nanocomposite as a high-performance barrier material in practical applications, typical organic light-emitting devices are encapsulated, and their lifetime is evaluated.

Here, we report on the synthesis of a silica nanoparticle (NP)-reinforced oligosiloxane nanohybrid material (SM-nanocomposite) and demonstrate its properties as a robust transparent hard coating material for various applications. The oligosiloxane (MMO) resin as a matrix was synthesized using methyl and methacryl silanes via a hydrolytic sol-gel condensation. The silica NPs with various sizes (12, 20 and 60 nm) as nanofillers were also synthesized through a hydrolytic sol-gel condensation, and the surface of NPs was organically modified with methyl and methacryl functions, which allowed stable dispersion and chemical cross-linking of the NPs with MMO matrix. In this work, we introduce synthetic steps of the nanocomposite and discuss the optical, morphological, thermal and mechanical properties of the composite.

Here, we report on the synthesis of a silica nanoparticle (SNP)-embedded urethane acrylate (UA) nanohybrid material (SNP-UA) and demonstrate its performance as photo-patternable transparent hard coating for optical applications. The SNP (10–20 nm) were synthesized via a base-catalyzed sol-gel condensation and the surface of SNP was chemically modified with methyl and methacryl organic functions by simple and mild solution processes, which not only enabled complete dispersion of SNP in the UA matrix but also rendered chemically cross-linked hybrid network of the SNP-UA. As an UV-curable optical hard coating, the SNP-UA exhibited excellent optical transparency coupled with a tunability of refractive index, good anti-scratch performance, and photo-patternability.

Iron sulphate roasting and water leaching were investigated to extract lithium from lepidolite in this study. HSC modelling was used to simulate the process of roasting lepidolite with FeSO 4 ·7H 2 O and CaO. Based on HSC, three-dimensional models were derived to predict the effect of temperature, SO 4 /Li and Ca/F molar ratios on the production of S- and F-containing gases (SO 2 , SO 3 , HF) and Li species (Li 2 SO 4 , LiKSO 4 ) during roasting. It is believed that temperature and SO 2 /SO 3 gases controlled the extraction of lithium from lepidolite during roasting while more soluble Li sulphate species determined the recovery of lithium during leaching. Using optimum parameters selected from HSC, roasting tests were conducted to produce calcines for leaching. Optimum roasting conditions were experimentally determined as 850 °C, 1.5 h, and SO 4 /Li and Ca/F molar ratios of 3:1 and 1:1, respectively. Roasting in a closed environment led to more Li extracted than with an open system. Leaching the calcines obtained from the open and closed systems with a water/calcine mass ratio of 1:1 at room temperature for 1 h yielded leach liquors containing ~ 7.9 g/L Li and ~ 8.7 g/L Li, corresponding to ~ 85% and ~ 93% extractions of Li from lepidolite, respectively.

Nanostructures of single crystallites of spinel LiMn2O4 (LMO) were prepared by the simple pyrolysis of aqueous solution of LiNO3 and Mn(NO3)2 in a confined space such as either droplets or mesopores. When the mixed nitrate solution was spray pyrolyzed at temperatures below 700 °C, 1-μm LMO spheres were obtained consisting of ~20-nm single crystallites randomly packed. Such LMO phase, once obtained, would sustain for further heat-treatment. Next, new spraying solution was prepared by adding the precursor for mesoporous silica (MPS) to the nitrates solution. By spray pyrolyzing such solution, LMO was impregnated inside pores of the MPS being structured. The silica could be removed by subsequent NaOH treatment to leave spherical LMO mesophase. The nitrates was also able to soak into the existing MPS having cylindrical pores and form short isolated LMO chains in the mesopores by the subsequent heating. After the same NaOH treatment, the LMO phase turned into bundles of very ‘long’, and often straight, chains, consisting of 8-nm LMO nanoparticles. This will be elucidated through further study.

Containing 10.2 Mt Li, Salar de Uyuni is known to be the richest resource of Li in the world. A high Mg/Li mass ratio of 21.2:1 of the Uyuni salar brine used in this study is a significant factor hindering the effective lithium recovery. Stabcal modelling was first conducted to study the conditions and chemical speciation of various species involved in the selective precipitation of Mg and Ca oxalate. Along with the addition of oxalic acid, the effect of pH was then studied in order to determine optimal conditions to selectively remove Ca and achieve high Mg yield subsequently. At an Oxalate/Ca molar ratio of 6.82:1 and pH 95% Mg was obtained (precipitate containing mostly Mg oxalate) together with the K and Li losses of up to 35% from the original brine. Washing would remove Li, K contaminants and the co-precipitated sodium sulphate and oxalate . Their absence from the final precipitate was confirmed by XRD analysis. The high purity (99.5% grade) Mg precipitate obtained could be used as a precursor for MgO production.

Key factors controlling the extraction of lithium from a lepidolite concentrate (2.55% Li) using a two-stage process based on roasting with Na2SO4 and water leaching were determined in this study. HSC software was used to predict lepidolite decomposition characteristics and products yielded from roasting. From this simulation roasting was conducted at 850–1000 °C with different sodium sulphate additions (set at sodium sulphate-lithium molar ratios of 1:1 to 3:1) in 0.5–2 h to yield several calcines for leaching. Stabcal modelling was applied to investigate the stability of various Li species formed during water leaching. From the simulation it was identified that LiKSO4, as one of the main Li-containing products formed in the calcine, has a low solubility and therefore controls the release of Li into water during leaching. The low solubility of LiKSO4 at 25 °C indicated by Stabcal was confirmed during leaching at different water–calcine mass ratios from 5:1 to 15:1. Leaching under these conditions only yields liquors containing

A hydrometallurgical process was developed to recover lithium from a brine collected from Salar de Uyuni, Bolivia, which contains saturated levels of Na, Cl and sulphate, low Li (0.7–0.9 g/L Li) and high Mg (15–18 g/L Mg). Unlike other commercial salar brines currently being processed, the high levels of magnesium and sulphate in Uyuni brine would create difficulties during processing if conventional techniques were used. A two-stage precipitation was therefore first adopted in the process using lime to remove Mg and sulphate as Mg(OH) 2 and gypsum (CaSO 4 .2H 2 O). Boron (at 0.8 g/L in the raw brine), a valuable metal yet deleterious impurity in lithium products, could also be mostly recovered from the brine by adsorption at a pH lower than pH11.3 in this first stage. The residual Mg and Ca (including that added from lime) which were subsequently precipitated as Ca–Mg oxalate could be roasted to make dolime (CaO ∙ MgO) for re-use in the first stage of precipitation. Evaporation of the treated brine up to 30 folds would produce 20 g/L Li liquors. The salt produced during evaporation was a mixture of NaCl and KCl, containing acceptable levels of sulphate, Mg, Ca, etc. The final precipitation of lithium at 80–90 °C produced a high purity (99.55%) and well crystalline lithium carbonate.

Photocurable inorganic–organic hybrid materials were prepared from colloidal-silica nanoparticles synthesized through the sol–gel process and using acryl resin. The synthesized colloidal-silica nanoparticles had uniform diameters of around 20 nm and were organically modified, using methyl and methacryl functional silanes, for efficient hybridization with acryl resin. The organically modified and stabilized colloidal-silica nanoparticles could be homogeneously hybridized with acryl resin without phase separation. The successfully fabricated hybrid materials exhibit efficient photocurability and simple film formation due to the photopolymerization of the organically modified colloidal-silica nanoparticles and acryl resin upon UV exposure as well as an excellent optical transmission of above 90% in the visible region and an enhanced surface smoothness of around 1 nm RMS roughness. They likewise exhibit improved thermal and mechanical characteristics, much better than those of acryl resin. Lastly and most importantly, these photocurable hybrid materials fabricated through the synergistic combination of colloidal-silica nanoparticles with acryl resin are candidates for optical and electrical applications.

The electrical insulation properties and the tracking and erosion resistances of high-temperature vulcanized silicone rubber were investigated as to the concentration of alumina trihydrate (ATH) therein for the fabrication of silicone rubber with optimum ATH content. Controlling the ATH concentration has been found to be an important factor in the enhancement of the tracking and erosion resistances of silicone rubber. In addition, the silicone rubber showed constant electrical resistivity and dielectric breakdown voltage without any decrease due to the interfacial problems with the addition of ATH to the silicone rubber. Therefore, this fabricated silicone rubber that contains an optimum ATH concentration can be applied to outdoor high-voltage insulators.

Fluorinated inorganic-organic hybrid materials (HYBRIMER) were successfully prepared from fluoroalkylsilanes (FASs) containing fluoro-alkyl functions and methacryloxypropyltrimethoxysilane (MPTMS) through a sol-gel process. The influence of concentration and fluoro-alkyl chain lengths of FASs on the physical characteristics of the fluorinated HYBRIMER films was examined. Larger fluorine contents lowered the refractive index within a range, which was closely dependent on the fluoro-alkyl chain lengths of FASs. Thermo-optic coefficients (TOC) were negative values, and the values grew with increasing fluorine contents and fluoro-alkyl chain lengths. Also, the thermal stability is enhanced by addition of fluorine in the HYBRIMER.

Organically modified germanosilicate (ORMOGSIL) glasses prepared by a sol-gel method showed a large refractive index change on ultraviolet exposure. The large photoinduced refractive index change in the ORMOGSIL glasses is mainly due to the structural densification caused by ultraviolet irradiation. The shifts in frequency of the Raman bands measured at room temperature reveal structural densification by reduction of the average intertetrahedral bonding angle θ in the ORMOGSIL glasses. Surface relief patterns by photoinduced densification were directly inscribed on the ORMOGSIL glasses.