Dual char-forming strategy driven MXene-based fire-proofing epoxy resin coupled with good toughness.

It is challenging that the functionalized MXene-based nanofillers are designed to modify the inherent flammability and poor toughness of epoxy polymeric materials and further to facilitate the application of EP composites. Herein, silicon-reinforced Ti3C2Tx MXene-based nanoarchitectures (MXene@SiO2) are synthesized by simple self-growth method, and its enhancement effects on epoxy resin (EP) are investigated. The as-prepared nanoarchitectures realize homogeneous dispersion in EP matrix, indicating well performance-enhancing potential. The incorporation of MXene@SiO2 achieves improved thermal stability for EP composites with higher T-5% and lower Rmax values. Moreover, EP/2 wt% MXene@SiO2 composites obtain a 30.2% and 34.0% reduction in peak heat release rate (PHRR) and peak smoke production rate (PSPR) compared to those of pure EP, respectively, also achieving a 52.5% fall in smoke factor (SF) values and increased yield and stability of chars. The dual char-forming effects of MXene@SiO2 nanoarchitectures, including the catalytic charring of MXene and the migration of SiO2 to induce charring, are accounted for the results, as well as lamellar barrier effects. Additionally, EP/MXene@SiO2 composites achieve an enhanced storage modulus of 51.5%, along with improved tensile strength and elongation at break, compared to those of pure EP.

Construction of Ti3C2 MXene based fire resistance nanocoating on flexible polyurethane foam for highly efficient photothermal conversion and solar water desalination.

In this work, a bilayer nanocoating was constructed on the surface of flexible polyurethane (FPU) foam with Ti3C2 MXene and polyethyleneimine-modified silica nanoparticles (mSiO2-NP@PEI) through layer-by-layer self-assembly technology, successfully obtaining modified flexible polyurethane composites (MFPU) with excellent flame retardancy, photothermal conversion and solar water desalination properties. The structure and morphology of MFPU foams were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Transmission electron microscope (TEM) and Scanning electron microscope (SEM). The MFPU with three coating cycles (MFPU3) had the best flame retardancy and smoke suppression performances, mainly in terms of decreased peak heat release rate (pHRR), peak smoke production rate (pSPR) and total smoke production (TSP) by 71.3 %, 62.1 % and 74.5 %, respectively, compared to those of neat FPU. In addition, MFPU foams exhibited extraordinary light-to-heat conversion and solar water desalination capabilities. MFPU3 could reach 120 °C in 138 s and its steam conversion efficiency η was as high as 89.6 %, which was 116.0 % higher than that of unmodified foam and had a 262.8 % increase over pure water. The flame retardant MFPU foams with excellent photothermal conversion efficiency will exhibit great application potential in solar water desalination and power generation.

Flame-retardant activity of ternary integrated modified boron nitride nanosheets to epoxy resin.

In order to improve the fire safety of epoxy resin, ZIF-8 nanoparticle in-situ decorated boron nitride nanosheet (BN-OH/ZIF-8) is fabricated via self-assembly method and then ternary integrated BN-OH/ZIF-8/PA hybrids are prepared through the chemical etching effect of phytic acid. FTIR, XRD, XPS, TEM and TGA measurements are used to characterize the structure and morphology of the nanohybrids. The researches show that BN-OH/ZIF-8/PA not only uniformly distributed in EP matrix, but also improve the thermal stability of EP. The peak heat release rate, peak smoke production rate, total smoke production values, the fire growth index and peak CO production rate obtained from cone test are significantly decreased, demonstrating the reduction of the fire hazards of EP composites containing BN-OH/ZIF-8/PA. The nano barrier effect and catalytic activity of BN-OH/ZIF-8/PA may be conducive to suppress the release of combustible volatile products and heat, facilitate the formation of graphitized carbon layer, and protect matrix from flame damage. The ternary integrated method developed in this study explores a new way to improve the flame retardant properties of EP, thereby promoting its application range.

Waste to resource: preparation of an efficient adsorbent and its sustainable utilization in flame retardant polyurethane composites.

In order to realize the comprehensive utilization of industrial solid waste and the treatment of water eutrophication, the flower-like magnesium hydroxide (MH) was synthesized from phosphorus tailings by sulfuric acid hydrolysis and a hydrothermal method and then was modified with a metal organic framework (MOF) to remove the phosphates enriched in water through adsorption. Both MH and MOF-modified MH (MH@MOF) presented good removal performance of phosphates. The phosphate-adsorbed composites (MH-P and MH@MOF-P) were sustainably used as effective flame retardants for thermoplastic polyurethane (TPU) at low loadings by a solution blending method. The cone calorimetry test results showed that MH@MOF-P can significantly reduce the heat release rate (HRR), smoke production rate (SPR), total smoke release (TSR), CO release rate and CO2 release rate of TPU composites, compared with those of neat TPU. The novel strategy proposed in this work is of great significance for resource recycling, environmental governance and improving fire safety of polymer materials.