Aqueous Self-Assembly of Bio-Based Flame Retardants for Fire-Retardant, Smoke-Suppressive, and Toughened Polylactic Acid

In this study, the heat-resistant hydrogen-bonded organic framework (HOF) material HOF-FJU-1 was synthesized via in situ generation and then used as flame retardants (FRs) to improve the flame retardancy of epoxy resin (EP). HOF-FJU-1 can maintain high crystallinity at 450 °C and thus function as a flame retardant in EP. The study found that HOF-FJU-1 facilitates the improvement of char formation in EP, thus inhibiting heat transfer and smoke release during combustion. For EP/HOF-FJU-1 composites, the in situ-generated HOF-FJU-1 can remarkably improve both the mechanical properties and the flame retardancy of EP. Furthermore, the in situ-generated HOF-FJU-1 has better fire safety than the ex situ-generated HOF-FJU-1 at the same filling content. Thermal degradation products and flame retardation mechanisms in the gas and condensed phases were further investigated. This work demonstrates that the in situ-generated HOF-FJU-1 is promising to be an excellent flame-retardant candidate.

Section: Resultsmentioning

confidence: 96%

Section: Char Residue Analysis Of Ep Compositesmentioning

confidence: 99%

In Situ-Generated Heat-Resistant Hydrogen-Bonded Organic Framework for Remarkably Improving Both Flame Retardancy and Mechanical Properties of Epoxy Composites

Zou,

Cui,

Chen

et al. 2023

“…The main pyrolysis product in the first stage is water, and the products in the second stage are water and ammonia. Combined with the XPS analysis of the char residue after TGA (Figure d), the peaks around 134, 133, and 132 eV are attributed to C–O–P, P 2 O 7 4– , and P–N, respectively. − …”

Section: Resultsmentioning

confidence: 99%

Influence of the Crystal Structure of Melamine Trimetaphosphate 2D Supramolecules on the Properties of Polyamide 6

Feng

et al. 2023

To explore the influence of the crystal structure difference of melamine trimetaphosphate (MAP) on the application performance of its polymer composites, an intumescent flame retardant with the optimal crystal type was designed and synthesized to improve the mechanical properties and flame retardancy of polyamide 6 (PA6). I-MAP and II-MAP were obtained using different concentrations of MA and sodium trimetaphosphate (STMP) in an acidic aqueous solution. The morphology, chemical composition, and thermal stability were comprehensively characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The dispersion, mechanical properties, and flame retardancy of PA6/I-MAP and PA6/II-MAP were evaluated by SEM, stress and strain, limiting oxygen index test (LOI), vertical burning test (UL-94), cone calorimetry (CONE) test, and char residue analysis. The conclusion is as follows: I-MAP and II-MAP have a greater influence on the physical properties of PA6 but less influence on the chemical properties. Compared with PA6/I-MAP, the tensile strength of PA6/II-MAP is 104.7% higher, the flame rating reaches V-0, and PHRR is reduced by 11.2%.

“…The TPP@ PVDF/SiO 2 /GO separator after combustion exhibited high graphitized carbon content, which also indicated that combustion promoted the formation of graphitized carbon and thus effectively improved thermal resistance and heat transfer. 59 Hence, TPP mainly played the role of fire extinguishing to prevent the temperature around the separator from further rising and heat transfer, which was like a "sword of fire extinguishing". GO and SiO 2 enhanced the thermal stability of the separator, and at the same time, GO provided a protective layer to isolate heat, acting as a "shield"; thus, the two factors finally made the TPP@PVDF/SiO 2 /GO separator exhibit an excellent fire prevention effect, as shown in Figure 3d.…”

Section: Flame-retardant Property and Thermal Stabilitymentioning

confidence: 99%

Coaxial Electrospun Tai Chi-Inspired Lithium-Ion Battery Separator with High Performance and Fireproofing Capacity

Zeng,

Shao,

Shen

et al. 2023

Organic flame-retardant-loaded battery separator offers a new opportunity for battery safety. However, its poor thermal stability still poses serious safety issues. Inspired by Tai Chi, an "internal-cultivating and external-practicing" core−shell nanofibrous membrane was prepared by coaxial electrospinning, wherein the shell layer was a mixture of polyvinylidene fluoride, silicon dioxide (SiO 2 ), and graphene oxide (GO) and the core layer contained triphenyl phosphate (TPP). SiO 2 and GO enhanced the thermal stability and electrochemical performance. The encapsulated TPP prevented heat transfer and the degradation of electrochemical performance caused by its direct dissolution. This separator exhibited outstanding thermal stability and flame retardancy: it did not burn and remained relatively intact (91.2%) in an open flame for 15 s. The battery assembled with a composite separator showed excellent performance: the initial capacity reached 164 mA h/g and maintained 95% after 100 charge− discharge cycles. This novel strategy endows high-performance lithium batteries with relatively higher safety.