Search

The good mechanical performances and caries inhibition of resin composites (RCs) are of great importance in dental restoration. Generally, the addition of SiO2 can improve the mechanical properties of RCs, while the introduction of fluoride (F) ions is capable of preventing caries. In this work, we first report the use of CaF2/SiO2 core–shell nanoparticles (CaF2/SiO2 NPs) as novel fillers for developing RCs with excellent mechanical properties and sustained F release. The results show that the superior performances of RCs can be obtained by filling 50 wt.% CaF2/50%SiO2 NPs, where the flexural strength, flexural modulus, compressive strength, and hardness were, respectively, increased by 111.5%, 41.4%, 61.7% and 66.8%, compared with the RCs filled with CaF2 nanoparticles. In addition, the initial F-release rate of RCs containing 50 wt.% CaF2/50%SiO2 NPs was 2.5 ± 0.4 μg/(h cm2), while the sustained release rate and the F release ratio were 0.96 ± 0.15 μg/h·cm2 and 5.22‰ after 1632 h (68 days), respectively. It was much more stable and sustained compared with the counterpart filled with CaF2 NPs. Therefore, it could be envisioned that CaF2/SiO2 NPs have a great potential as inorganic fillers in dental RCs. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide/graphene (MoS2/rGO) nanocomposites are a promising candidate for energy storage materials. However, it is still a challenge to uniformly disperse MoS2 on rGO nanosheets, which the performance mainly depends on. In this work, we demonstrate a novel method to synthesize the three-dimensional (3D) MoS2/rGO nanocomposites by the high-gravity reactive precipitation in a rotating packed bed (RPB) reactor combined with the hydrothermal method. The prepared nanocomposites have higher purity and larger specific surface area than that prepared in the traditional stirred tank reactor (STR). More importantly, MoS2 is uniformly and densely dispersed on rGO nanosheets, resulting in the formation of an even 3D network structure and contributing to the achievement of excellent energy storage performance. The specific capacitance of the nanocomposites reaches 294 F g−1 at a scan rate of 20 mV s−1, which is obviously higher than that of pure MoS2 (122 F g−1) and rGO (23 F g−1). The calculated energy density and power density are 57 Wh kg−1 and 50 W kg−1, respectively. Moreover, the preparation process is environmentally friendly, controllable and suitable for a large-scale production, which is significantly important for the development of the electrode materials applied in the supercapacitors. [ABSTRACT FROM AUTHOR]

Transparent ZnO/polymer nanocomposites with good UV shielding performance have shown great potential applications. Due to the photocatalytic activity of ZnO, core-shell structure nanoparticles (NPs) have been used to fabricate the transparent polymer-based nanocomposites. However, it is still a challenge to synthesize core-shell structure NPs with small particle size and good dispersity, and difficult to maintain the transparency of the nanocomposites because of Rayleigh scattering caused by the big size or the aggregation of NPs. This article reports a novel reverse microemulsion combined with surface modification method for the synthesis of monodispersed silica-coated ZnO (ZnO@SiO2) NPs, which are introduced into ethocel (EC) matrix to fabricate the transparent nanocomposites by the solution-mixing method. The ZnO@SiO2 NPs with an average size of 12 nm have an obvious core-shell structure and show excellent monodispersity in toluene. The as-prepared EC/ZnO@SiO2 nanocomposites shield all the UV light completely under 350 nm and maintain the transparency of pure EC even the solid content reaches 60 parts per hundred of EC resin by weight (phr). Importantly, the photocatalytic activity of ZnO NPs is eliminated thoroughly by the silica shell, which apparently improves the UV aging resistance of polymer (EC), enabling the applications of ZnO as durable and environmental friendly UV blocker in transparent plastics and coatings to extend the lifetime of the products. [ABSTRACT FROM AUTHOR]

A facile high-gravity strategy is proposed for preparation of Mg(OH)/graphene oxide (MGO) composite using a rotating packed bed reactor at room temperature for 1 min. Lamellar Mg(OH) nanocrystals of about 60 nm in diameter with a narrow size distribution are distributed homogeneously on the graphene oxide sheets without aggregation. The specific surface area of MGO with mesoporous structure reaches 590 m g, which is the highest among those reported in the literatures. The as-prepared MGO nanocomposite exhibits excellent adsorption capacity for methylene blue (MB). The removal rate of MB reaches 98% in 1 min. The preparation process of MGO nanocomposite is rapid, simple, and suitable for a large-scale production, and the product has great potential in the field of environmental protection as a promising absorbent. [ABSTRACT FROM AUTHOR]