Preparation of DOPO-KH550 modified hollow glass microspheres/PVA composite aerogel for thermal insulation and flame retardancy

The creation of high-performance thermal insulation and flame-retardant materials is of great importance for minimizing energy consumption and reducing fire risk for modern buildings. Herein, we report the creation of a new composite aerogel, which was prepared by incorporation of 9,10-Dihydro-9-oxa-10-phosphaphenanthrene 10-Oxide-3-Aminopropyl triethoxysilane (DOPO-KH550) modified hollow glass microspheres (HGM) into polyvinyl alcohol (PVA) using citric acid as a cross-linker, as a kind of thermal insulation and flame retardant materials (abbreviated as PVA-DKHGM). The as-synthesized PVA-DKHGM composite exhibits superior thermal conductivity of 0.0187 W m-1 K-1, owing to the hollow structure of the hollow glass microspheres and rich porosity. Besides, it reaches V-0 level at the UL-94 test and the peak heat release rate (pHRR) was measured to be 114.93 (kW/m2) which is lower than most composites now. These results are attributed to the synergy effect of the hollow glass microsphere and DOPO-KH550 which offers the composites aerogel excellent flame retardancy. Owing to its advantages such as lightweight, highly porous, thermally stable, simple to prepare, high mechanical strength, and can be further scaled up, our PVA-DKHGM aerogel may hold great potential for practical applications in construction of energy-saving modern buildings.

Review and prospects of mining chemical dust suppressant: classification and mechanisms

Coal mine pollution is a serious threat to the mine safe production and occupational health of miners. Chemical dust suppression can effectively reduce the concentration of coal dust and suppress the re-entrainment of dust. This paper discusses the research progress of three kinds of traditional dust suppressants: the wetting-type, cohesive type, and condensed type. In order to meet dust suppression and environmental protection requirements, 7 kinds of new type dust suppressants, such as compound, ecological environmental protection, polymer, functional, microbes, and enzymes, have been developed by the predecessors. And all kinds of dust suppressant mechanism and main performance index have been summarized. Through the analysis of the research results from 1985 to 2021, it is found that the compound and environment-friendly dust suppressants have gradually become the research focus in this field, accounting for 17.93% and 26.21% of the total number of achievements. In the recent 5 years, new materials, such as microbe suppressant, urease suppressant, and nanomaterials, have gradually emerged. Because of their natural and environmental protection characteristics, it could be predicted that they will become the future development trend in this field. However, there are still some problems to be improved, such as expensive price and complex preparation technology.

Synthesis and Characterization of Thermosensitive P(NIPAAm-co-AAc)-Grafted Silica Nanocomposites for Smart Architectural Coatings

In this study, a new class of thermosensitive poly(N-isopropylacrylamide)-co-poly(acrylic acid) (P(NIPAAm-co-AAc))-grafted modified silica (m-silica) nanocomposites was prepared using a sol-gel technique. The addition of silica to P(NIPAAm-co-AAc) copolymer hydrogel has the potential to open up new applications in the development of thermosensitive building materials by leveraging the favorable thermal characteristics of P(NIPAAm-co-AAc). The silica was prepared using 3-aminopropyltriethoxysilane and 4,4'-azobis(4-cyanovaleric acid) to form the m-silica powder, which increased the adhesion between the organic and inorganic hybrid materials. The P(NIPAAm-co-AAc) copolymer hydrogel was mixed with the m-silica to form the P(NIPAAm-co-AAc)-grafted m-silica nanocomposites. Scanning electron microscopy, X-ray diffraction analysis, thermogravimetric analysis, Fourier-transform infrared spectroscopy, and thermosensitive measurement were conducted to evaluate the structure and water-holding capacity of the nanocomposites. The results indicated that the P(NIPAAm-co-AAc)-grafted m-silica nanocomposites could retain water for more than 300 min at temperatures higher than the lower critical solution temperature. The P(NIPAAm-co-AAc)-grafted m-silica nanocomposites exhibited favorable thermosensitive properties and may therefore be applied in smart architectural coatings.