Synthesis and Properties of a Photopolymerizable Carbene-Mediated Poly Phosphinate Flame Retardant by Carbene Polymerization

A novel photopolymerizable poly phosphinate (poly ethyl (4-acrylamidebenzyl)­phosphinate, P-NH-AC) flame retardant was synthesized by a carbene polymerization and characterized using Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), and gel permeation chromatography (GPC). The effect of P-NH-AC on the kinetics of photopolymerization, thermal stability, combustion behaviors, and physical and mechanical properties of the UV-cured materials were investigated by real-time infrared spectroscopy (RT-IR), thermogravimetric analysis (TGA), thermogravimetric analysis/infrared spectrometry (TGA-IR), the limiting oxygen index (LOI), and the cone calorimetric test (CCT). For the systems with P-NH-AC, the thermal stability was improved with the increase of the P-NH-AC; however, the final residue of all systems was low. The addition of 5% P-NH-AC increased the LOI from 29.0 to 32.0. The addition of P-NH-AC significantly decreased the heat release rate (HRR), total heat release (THR), and total smoke production (TSP) of the resin. Moreover, P-NH-AC can also improve physical and mechanical properties of the materials

Self-Template Etching Synthesis of Urchin-Like Fe₃O₄ Microspheres for Enhanced Heavy Metal Ions Removal

Hierachical Fe₃O₄ microspheres with superparamagnetic properties are attractive for their superior structural, water-dispersible, and magnetic separation merits. Here self-template etching route was developed to create optimal porous structure in superparamagnetic Fe₃O₄ microspheres by using the oxalic acid (H₂C₂O₄) as etching agent. A plausible formation mechanism of the urchin-like Fe₃O₄ microspheres was proposed based on systematic investigation of the etching process, which involved two stages including pore-forming step based on size-selective etching and pore-expanding step based on further etching. The as-synthesized Fe₃O₄ microspheres exhibited urchin-like structure with specific surface area and pore-size tunable, water-dispersible, and superparamagnetic properties. The optimal urchin-like Fe₃O₄ microspheres demonstrated superior performance including fast magnetic separation and high removal capabilities for the heavy metals ions like Pb²⁺ (112.8 mg g^–1) and Cr­(VI) (68.7 mg g^–1). This work will shed new light on the synthesis of urchin-like microspheres for superior performance

Observation of Cluster Size Growth in CO-Directed Synthesis of Au₂₅(SR)₁₈ Nanoclusters

The design of an efficient synthesis for large-scale production of atomically precise nanoclusters (NCs) is pivotal in realizing the size-dependent properties of the NCs. A simple and versatile method for producing atomically precise thiolated gold NCs (Au₂₅(SR)₁₈ NCs) in large quantities (∼200 mg) is demonstrated in this study. It uses a gaseous reducing agent, carbon monoxide (CO), to support a slow and size-controlled growth of Au₂₅(SR)₁₈ NCs. Absorption measurements of the reaction solution, which underwent distinct color changes (colorless → yellow → orange → brown → red-brown), allowed the formation of thiolated Au₂₅ NCs to be reconstructed from several key intermediates. The unique reaction environment provided by gaseous CO presents a new synthetic route to fabricate atomically precise metal NCs in quantities large enough for application explorations

Synthesis and characterization of photosensitive-fluorosilicone–urethane acrylate prepolymers

<div><p>Two kinds of novel photosensitive-fluorosilicone–urethane acrylate prepolymers (Si-F15-IPDI-HEA/Si-F6-IPDI-HEA) were synthesized and characterized. Si-F15-IPDI-HEA and Si-F6-IPDI-HEA were able to form homogeneous mixtures with a number of acrylate monomers. Formulations with these prepolymers with common acrylic monomers exhibited high-polymerization rates and final double-bond conversion over 90% after irradiation for 60 s. It was found the final conversion decreased with the increase of the functionality of the monomer. The influence of the monomer and prepolymers on the properties of the UV-cured films was systematically studied. Thermostability property along with mechanical performance was improved with the increase of the functionality of monomers and prepolymers. A decrease of water absorption was also observed through water contact angle measurements. The UV-cured films of Si-F15-IPDI-HEA and Si-F6-IPDI-HEA possessed an excellent adhesion on the PU and PVC leather, providing a potential application in leather industry as a finishing and coating agent.</p></div

Gadolinium-Doped Ceria–NaCoO₂ Heterogeneous Semiconductor Ionic Materials for Solid Oxide Fuel Cell Application

Solid oxide fuel cells (SOFCs) possess the merits of high power density, high energy conversion efficiency, and low emissions with diverse fuels and have attracted wide attention in the energy fields. However, the excessively high operating temperature limits its commercialization from aspects of cost and durability. It is urgent to find other ceramic membrane materials with superionic conductivity at low and intermediate temperatures to reduce the temperature of SOFCs. Semiconductor ionic composites based on oxide semiconductors can be used as heterogeneous functional membrane materials to develop low-temperature SOFCs. Herein we report a heterostructure material formed by gadolinium-doped ceria (GDC) and NaCoO2 (NCO) as a functional membrane. The fuel cell with the optimized functional composite membrane achieved a peak power density of 1097 mW·cm–2 at 550 °C, in which an ionic conductivity of 0.33 S·cm–1 at 550 °C was obtained for the heterostructure composite. Proton conduction in the heterostructure composite was confirmed by X-ray photoelectron spectroscopy, Raman spectroscopy, and electrochemical impedance spectroscopy. Interfacial proton-transport and bulk oxygen-ion conduction mechanisms are proposed and discussed

Synthetic Strategy and Performances of a UV-Curable Poly Acryloyl Phosphinate Flame Retardant by Carbene Polymerization

<div><p>GRAPHICAL ABSTRACT</p><p></p></div

A 68 years old male patient with cancer in the right lung.

<p>(A) Axial image with region-of-interest indications for measuring CT number and standard deviation: bronchial artery blood vessels (blue), adjacent tissues in mediastinum (green), and subcutaneous fat on chest wall (purple). (B) Plot of contrast-to-noise ratio(CNR) as function of photon energy showing the optimal energy level of 63keV to obtain the highest CNR for the bronchial artery. (C) Volume-rendering (VR) 140kVp image with image quality score of 3. (D) VR image at 70 keV with image quality score of 4. (E) VR image at the optimal 63 keV with image quality score of 5.</p

Scoring criteria for bronchial artery.

<p>Scoring criteria for bronchial artery.</p

Fast Synthesis of Thiolated Au₂₅ Nanoclusters via Protection–Deprotection Method

This letter reports a new synthesis strategy for atomically precise Au nanoclusters (NCs) by using a protection–deprotection method. The key in our synthesis strategy is to introduce a surfactant molecule to protect thiolate-Au^I complexes during their reduction. The protecting layer provides a good steric hindrance and controls the formation rate of thiolated Au NCs, which leads to the direct formation of atomically precise Au NCs inside the protecting layer. The protecting layer was then removed from the surface of thiolated Au NCs to bring back the original functional groups on the NCs. The protection–deprotection method is simple and facile and can synthesize high-purity thiolated Au₂₅ NCs <i>within</i> 10 min. Our synthesis protocol is fairly generic and can be easily extended to prepare Au₂₅ NCs protected by other thiolate ligands

Comparison of signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and Subjective image quality score for bronchial artery among images of three energy levels.

<p>Comparison of signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and Subjective image quality score for bronchial artery among images of three energy levels.</p