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Abstract: A novel phosphate acrylate monomer (TGMAP) has been synthesized by allowing phosphoric acid to react with glycidyl methacrylate. Its structure was characterized by Fourier transformed infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance spectroscopy (1H NMR). The thermal degradation mechanism was characterized using thermogravimetric analysis/infrared spectrometry (TG-IR). The char yield was 36.3% at 600 °C. TG data indicate that the material undergoes degradation in three characteristic temperature stages, which can be attributed to the decomposition of the phosphate, thermal pyrolysis of aliphatic chains, and degradation of an unstable structure in char, respectively. The volatilized products formed on thermal degradation of TGMAP indicated that the volatilized products are CO, CO2, carboxylic acid, acid anhydride, water, alkane, and aromatic compounds according to the temperature of onset formation. [Copyright &y& Elsevier]

This article mainly studies synergistic flame retardant effects and smoke suppression properties of iron-graphene (IG) and aluminum hypophosphite (AHP) on thermoplastic polyurethane (TPU), AHP used as main flame retardants and IG used as synergistic agents. A high concentration of TPU/IG masterbatch was prepared by solution-blending method, and then TPU/AHP/IG composites were prepared by melt-blending method. Then, the flame retardant effects of all TPU composites were tested using limiting oxygen index (LOI), UL 94 test, cone calorimeter test (CCT), scanning electron microscopy (SEM), thermogravimetric analysis (TG) and thermogravimetric/fourier transform infrared spectroscopy (TG-IR). Remarkably, with 0.25 wt% content of IG and 9.75 wt% content of AHP, sample reached UL 94 V-0 rating, and the LOI value increased by 31.5 vol%, pHRR value decreased by 90% and pSPR value decreased by 72%, etc. SEM images show that char residues become more complete and present lamellar structure. TG-IR data reveal that the incorporation of AHP and IG promoted the release of H 2 O and CO 2 , meanwhile reduced harmful gases release. [ABSTRACT FROM AUTHOR]

• A nanohybrid with core-shell 3D cross-heterostructure, ZIF-67H@PBA, was synthesized. • Adding just 0.5wt% of ZIF-67H@PBA can effectively enhance flame retardant of TPU. • Cone calorimeter-Smoke sampling device-GCMS was constructed to show smoke release. • ZIF-67H@PBA showed high fire safe performance by catalyzing the carbonization of TPU. Thermoplastic polyurethane (TPU) has an extensive application in many different industries. However, serious fire hazards and smoke toxicity have been the main reason limiting its wide application. Therefore, it is necessary and urgent to perform flame retardant and smoke suppression treatment for TPU. In recent years, metal-organic framework compounds (MOFs) have very promising application prospects in the fields of flame-retardant polymer composites. However, there is a problem of low flame-retardant efficiency for the original MOFs alone in polymer composites. It is reported the multi-level and multi-structured flame-retardant system has better flame-retardant efficiency than the traditional structures. So, the dual MOF core-shell heterostructure may have more effective heat reduction and smoke suppression than any single component. In this paper, a core-shell 3D cross-heterostructures nanohybrid (ZIF-67H@PBA) was prepared using ZIF-67H as the host MOF and Prussian blue nanocubes (PBA) as the guest MOF. It has been found that TPU/ZIF-67H@PBA composites with ultra-low additions have excellent fire safety. Compared with those of pure TPU, the peak heat release rate (PHRR), total smoke release (TSP), and smoke factor (SF) of the samples with 0.5wt% ZIF-67H@PBA were reduced by 33.6 %, 47 %, and 61 %, respectively. At the same time, a cone calorimeter (CCT), a homemade soot sampling device and a gas chromatography-mass spectrometry (GC–MS) coupling with each other were constructed and used to demonstrate the most realistic effects of flame retardants in terms of smoke suppression and toxicity reduction. This work provides a new strategy to design TPU flame retardants. [Display omitted] [ABSTRACT FROM AUTHOR]

• A novel 3D cross-shaped ZIF-67 (ZIF-67 H) was designed. • ZIF-67 H provides TPUs with great flame retardancy and smoke suppression properties. • The catalytic flame retardancy mechanism of ZIF-67 H was summarized and speculated. Zeolite imidazolium frameworks (ZIFs), as a subcategory of metal-organic frameworks (MOFs), are widely used in many fields. And, the physical morphology, particle size, and shape of ZIFs have an important influence on their application performance, such as flame retardancy for polymer. Here, three types of ZIF-67 were prepared with different physical morphology structures including dodecahedron (ZIF-67), cube (ZIF-67 NC), and cross-shaped (ZIF-67 H), by adjusting the proportion between 2-methylimidazole and cobalt (Ⅱ) nitrate hexahydrate together with the suitable amount of surfactant (CTAB), and they were used to enhance the flame retardancy and smoke suppressing properties of thermoplastic polyurethane (TPU). It has been found the novel ZIF-67 H with 3D cross-shaped superior catalytic and flame-retardant capabilities than the other two during the burning process of TPU composites. Compared with those of pure TPU, the peak heat release rate (pHRR), total smoke production (TSP), and smoke factor (SF) of TPU/2 wt%ZIF-67 H were decreased by 45.4 %, 50.2 %, and 72.9 %, respectively. At the same time, both TPU/1 wt%ZIF-67 H and TPU/2 wt%ZIF-67 H samples showed stronger tensile properties than pure TPU at the same elongation. This work further enriches the study of multi-structured ZIFs for flame retardant TPU. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Flame retardant polylactide (PLA) composites were prepared using PLA and a hyperbranched polyphosphate ester (HPE). The flammability and thermal stability of flame retardant PLA composites were investigated by limiting oxygen index (LOI), UL-94 vertical burning, microscale combustion calorimetry (MCC), and thermogravimetric analysis/infrared spectrometry (TG-IR). The results showed that HPE had excellent flame retardant abilities for PLA. The TGA curves suggested that HPE has good ability of char formation, hence improved the flame retardant property. The volatilized products formed on thermal degradation of flame retardant PLA indicated that the volatilized products are mainly aldehyde containing compounds, CO, aliphatic esters, and CO2. [Copyright &y& Elsevier]

Abstract: A novel silicone and phosphate modified acrylate (DGTH) was synthesized and characterized by 1H NMR and FTIR. It was found that DGTH could be cured both by UV radiation and moisture mode with FTIR. The flammability and thermal behavior of the cured film were studied by the limited oxygen index (LOI), thermogravimetric analysis (TG) and real time Fourier transform infrared (RT-FTIR). The LOI value of the cured film is 48 and the TG data shows that the cured film has three characteristic degradation temperature regions, attributing to the decomposition of phosphate and polyurethane to alcohols and isocyanates, thermal pyrolysis of alkyl chains, and decomposition of unstable structures in char, respectively. The RT-FTIR data implies that the degraded products of phosphate form poly(phosphoric acid) further catalyse the breakage of carbonyl groups to form an intumescent char, preventing the samples from further burning. [Copyright &y& Elsevier]

• A green organic-inorganic PAbz@ZIF hybrid has been prepared. • 5.0 wt% of PAbz@ZIF allows EP to easily achieve a UL-94 rating of v0. • PAbz@ZIF hybrids endow EP with efficient flame retardancy and smoke suppression. • PAbz@ZIF hybrids improve the heat insulation performance and mechanical performance of EP. Developing sustainable bio-based flame retardants for flammable polymers has been a research trend. However, applying bio-based flame retardants to confer excellent flame retardancy, smoke suppression, and mechanical properties to polymers remains a formidable challenge. Herein, a green organic-inorganic hybrid (PAbz@ZIF) was readily prepared through a simple neutralization reaction and in-situ generation method and applied to fabricate high-performance flame-retardant epoxy coatings (EP-PAbz@ZIF). It has been shown that PAbz@ZIF hybrids can enhance the curing activity of epoxy coatings in addition to their excellent dispersibility and interfacial compatibility. In addition, the epoxy coating containing 5.0 wt% PAbz@ZIF (EP-5%PAbz@ZIF) exhibits a higher char yield (from 25.1 wt% to 31.5 wt%) in comparison to pristine epoxy resin (EP). More importantly, the PAbz@ZIF-based epoxy coatings show more efficient flame retardancy and smoke suppression compared to pristine EP. For instance, the 5.0 wt% PAbz@ZIF enables EP-5%PAbz@ZIF to obtain a satisfactory UL-94 rating of V0. Meanwhile, the peak heat release rate, total smoke production, peak CO production rate, and peak CO 2 production rate of EP-5%PAbz@ZIF are remarkably decreased by 48.6%, 20.5%, 38.6%, and 56.7%, respectively. Furthermore, EP-5%PAbz@ZIF exhibits enhanced heat insulation performance, flexural strength, and impact strength. This work offers a feasible idea for designing green organic-inorganic PAbz@ZIF hybrids and fabricating high-performance flame-retardant epoxy coatings. [Display omitted] [ABSTRACT FROM AUTHOR]

• A hierarchical MXene@PDA@CoFeOx has been constructed by a biomimetic strategy. • MXene@PDA@CoFeOx allows EP to easily achieve a UL-94 V0 rating. • MXene@PDA@CoFeOx endows EP with efficient flame retardancy and smoke suppression. • MXene@PDA@CoFeOx improves the thermal conductivity and mechanical performance of EP. Developing high-performance MXene-based polymer nanocomposites through a biomimetic method has been a research hotspot. However, it is still an intractable challenge to achieve MXene-based polymer nanocomposites with efficient fire safety, excellent thermal conductivity, and enhanced mechanical properties. Here, inspired by the adhesion of mussels, the hierarchical MXene@PDA@CoFeOx nanohybrid was fabricated by a self-assembly strategy and then employed to prepare epoxy resin (EP) nanocomposites. It has been found that MXene@PDA@CoFeOx can display excellent dispersion and interfacial compatibility in EP matrix. Thermogravimetric analysis shows that only 2.0 wt% MXene@PDA@CoFeOx results in excellent thermal stability and char yield (31.29 wt%) of EP under a nitrogen atmosphere. Combustion tests show that the 2.0 wt% MXene@PDA@CoFeOx confers efficient fire safety to EP. Remarkably, the EP-2.0%MXene@PDA@CoFeOx can obtain an attractive UL-94 rating of V0. Meanwhile, the peak heat release rate (pHRR), smoke factor (SF), and peak CO production rate (pCO) of EP-2.0%MXene@PDA@CoFeOx are dramatically decreased by 33.38%, 55.41%, and 36.84% in comparison to those of virgin EP, respectively. The efficient fire safety of EP nanocomposites is mainly attributed to the barrier effect, dilution effect, and catalytic carbonization effect of hierarchical MXene@PDA@CoFeOx. Furthermore, the MXene@PDA@CoFeOx enables EP to boast enhanced thermal conductivity (improved by 69.14%), impact strength (improved by 13.38%), and flexural strength (improved by 17.60%). This work offers a feasible biomimetic method for fabricating hierarchical MXene@PDA@CoFeOx nanohybrids and preparing efficient fire-safe EP nanocomposites with excellent thermal conductivity and mechanical performance. [Display omitted] [ABSTRACT FROM AUTHOR]

• A novel flame retardant was coated on the surface of cotton fabric via a straightforward step-by-step dip-coating method. • The introduction of AEP/IL/Cu significantly solves the problem of a large number of toxic smoke gasses released from Cot/AEP/IL. • Cot/AEP/IL/Cu significantly inhibited the production of toxic smoke gasses and improved the flame-retardant and antibacterial properties of the cotton fabric greatly. To meet the demands of reducing the serious illness caused by the growth of bacteria and the severe life-threatening due to interior fabric fire, the attention to antibacterial flame-retardant cotton fabrics has reached an unprecedented height. In this work, a simple step-by-step dip-coating method was applied for the multifunctional cotton based on epichlorohydrin-modified aramid nanofibers (AEP), ionic liquid (IL), and CuSO 4. Cot/AEP/IL/Cu exhibited low flammability with a limiting oxygen index (LOI) improving from 18.5% to 28.5% and high flame retardancy (e.g., ∼43.7% and 41.7% decline in peak heat release rate (pHRR) and total heat release rate (THR)). Noticeably, the Cot/AEP/IL/Cu revealed conspicuous smoke suppression and toxic reduction property compared with Cot/AEP/IL (e.g., ∼77.0% decline in peak smoke release rate (pSPR) and 40.5% in total CO production (TCOP)). In addition, the antibacterial property of treated cotton was investigated by the agar diffusion plate method. Due to the presence of Cu ion, Cot/AEP/IL/Cu remarkably restrains the activity of E. coli and S. aureus. This work prepared a multifunctional cotton fabric integrated with flame-retardant, smoke suppression, toxicity reduction, and antibacterial in a straightforward way, which endows promising applications in many fields. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: A series of flame retardant ethylene-vinyl acetate (EVA) composites, with different content of magnesium hydroxide (MH) and hollow glass microspheres (HGM), have been prepared. The synergistic flame retardant effects of HGM with MH in EVA/MH blends have been studied by limiting oxygen index (LOI), UL-94 tests, cone calorimeter test (CCT), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM), respectively. The LOI and UL-94 results show that when 2.00 wt% magnesium hydroxide (MH) is substituted with HGM, the LOI value can be raised to the maximum value of 42.1 among all samples. The data obtained from the CCT test indicate the heat release rate (HRR) of EVA/MH/HGM sample with 1.00 wt% HGM reduced by 37% when compared with EVA/MH sample without HGM. The digital photo graphs and scanning electron microscope (SEM) of char residues after CCT give positive evidence that the synergistic flame retardant effects between HGM and MH can be described that HGM mixed with MH can decrease the melt viscosity of EVA/MH/HGM, and promote the homogeneous dispersion of MH. HGM also can promote the formation of compact charred layers and prevent the charred layers from cracking, which effectively protects the underlying materials from burning. The TGA results reveal that EVA/MH/HGM samples show higher thermal stability at high temperature than EVA/MH sample. [Copyright &y& Elsevier]

• KH-560 acts as a bridge to connect boron nitride and ionic liquid, thus obtaining ionic liquid modified boron nitride nanosheets (BNO@IL). • Ionic liquid significantly enhances the interface interaction between boron nitride and epoxy resin. • After adding 2 wt% of BNO@IL nanosheets, the fire safety performance of epoxy resin composites is significantly enhanced compared with pure EP. Hexagonal boron nitride (h-BN) is more challenging to exfoliate into fewer layers than graphene due to the ionic bond between B and N atoms (lip-lip interaction) from adjacent layers. In this paper, boron nitride was exfoliated and hydroxylated by thermal oxidation in air. Hydroxylated boron nitride nanosheets (BNO) were modified by ionic liquids and added to epoxy resin to prepare epoxy matrix nanocomposites (EP/BNO@IL). The SEM results of EP/BNO@IL nanocomposites suggested that the introduction of ionic liquids enhanced the interfacial interaction between boron nitride nanosheets and epoxy resin (EP). Thermogravimetric (TG) results showed that introducing 2 wt% BNO@IL nanosheets improved the thermal stability of EP. In addition, cone calorimeter test (CCT) results showed that BNO@IL nanosheets enormously improved the fire safety performance of the epoxy resin. The peak heat release rate, total heat release, peak smoke release rate, and total smoke release of epoxy resin nanocomposites with 2 wt% BNO@IL nanosheets decreased significantly. In this work, the realization of ionic liquid modified boron nitride nanosheets (BNO@IL) provides new possibilities for improving the fire safety performance of EP. [ABSTRACT FROM AUTHOR]

• Phytic acid doped polyaniline-coupled g-C 3 N 4 (CP@PA) was synthesized as flame retardant for epoxy resin (EP). • CP@PA can improve the flame retardant efficiency and waterproof property of EP composites based on APP. • CP@PA could promote EP/APP to form a highly cross-linked network and char residue layer. In this study, polyaniline-coupled graphitic carbon nitride (g-C 3 N 4) doped with phytic acid (CP@PA) hybrids are prepared by an in-situ chemical oxidative method. The CP@PA and APP (Ammonium Polyphosphate) are added into epoxy resin (EP) for EP composites. The characteristic test results show that CP@PA can react with epoxy resin (EP) to promote the curing of EP. And CP@PA disperses in EP uniformly. The cone calorimetry test (CCT) results show that the pHRR, THR, and TSP of EP-8A4CP@PA (the EP sample with 8.0 wt% APP and 4.0 wt% CP@PA) reduce 85%, 76.8%, and 78.9%, respectively than EP-0 (pure EP), which are lower than any other samples. The results of the back temperature test show that EP-8A4CP@PA has better thermal insulation and flame-retardant properties than EP-12APP (the EP sample with 12.0 wt% APP). Moreover, CP@PA promotes the waterproof properties of EP with APP composites by synergizing with APP to form a labyrinth effect. After a comprehensive analysis, the fire protection mechanisms of EP-8A4CP@PA are proposed as follows. CP@PA promote EP charring and make more aromatic structure remain in the char. And CP@PA has a synergistic effect with APP to promote EP to form porous intumescent char layer with a higher graphitic degree, which protects the composites from the flame. As a result, the combination of CP@PA and APP in EP achieved a lower addition of flame retardant and better waterproof and fire safety performance, which provides a specific experimental and theoretical basis for the further application of CP@PA in epoxy resin. [ABSTRACT FROM AUTHOR]