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Lightweight wood‐plastic composites (WPC) are made from expandable polystyrene and wood particle using a mold foaming technique, and their fire resistance is improved with the addition of melamine phosphate (MPP) and aluminum hypophosphite (AHP). Flame retardancy is characterized and shown to be significantly enhanced on limiting oxygen index (LOI), vertical burning test (UL‐94), and cone calorimetry tests. The fire behavior investigation indicates that the LOI value of WPC/12MPP/3AHP sample can reach 33.5% and UL‐94 rating was V‐0. The total heat release, total smoke production, peak of smoke production rate and peak of heat release rate of WPC/15MPP are reduced by 23.2%, 47.5%, 28.6% and 17.3%, respectively, compare with the pure one. Mechanical properties characterization of composites also reveals that MPP/AHP has a positive influence on the impact strength, modulus of elasticity and modulus of rupture. [ABSTRACT FROM AUTHOR]

The preparation of wood products with mechanical reinforcement, flame retardancy, and water resistance is still a problem to be solved. In this work, carbonated apatite (CAp) was bio-mineralized in wood vessel by the method of gradient impregnation. The CAp@wood75G sample with the weight gain of 75 wt% showed the greatest bending strength and compressive strength due to the formation of organic–inorganic composites. With the high bending strength and compressive strength, the CAp@wood75G sample exhibited elevated limiting oxygen index (LOI) of 60.4% and self-extinguished immediately in the vertical burning test. In cone calorimetry test, the peak of heat release rate and total heat release for CAp@wood75G sample were lessened by 68.2 and 53.1% respectively, compared with that of natural wood sample. Furthermore, the LOI of CAp@wood75G with self-extinguishment was still as high as 38.4% even after immersed in water for 24 h. Furthermore, the flame retardant mechanism was explored and generalized. The CAp was decomposed to produced CO2 and H2O to dilute the combustible gases in the air, and catalyzed wood to form the barrier of heat and oxygen during burning. Moreover, CAp produced inorganic salts which played the protective layer role. To conclude, this efficient processing method by bioinspired mineralization was eco-friendly and effective. [ABSTRACT FROM AUTHOR]

Nylon-cotton (NYCO) blend fabrics have been widely used recently; however, they are susceptible to ignition when exposed to flame. Herein, 3-glycidyloxypropyl trimethoxy silane (GPTMS) associated with polyethyleneimine (PEI) and phytic acid (PA) was incorporated on NYCO fabrics through the facile sol–gel and dip-nip-dry method to prepare flame retardant NYCO fabrics with enhanced washing durability. The limiting oxygen index (LOI) value of treated NYCO fabrics was increased from 18.5 to 29.8% and the damaged length was reduced from 30 to 7.5 cm. Cone calorimeter test indicated that the peak heat release rate and total heat release were decreased by 73 and 79% respectively, compared with that of the control NYCO fabrics. The flame retardancy was well maintained and showed self-extinguishing behavior after 20 laundering cycles. The char formation ability was reinforced and the possible flame retardant mechanism was proposed. Moreover, the dermal irritation test showed good biological safety of the fabrics, which were incapable to cause erythema and edema on rabbit skin. This study proposed a feasible method to produce flame retardancy, durability, and bio-safety nylon-cotton blend fabrics by textile finishing. [ABSTRACT FROM AUTHOR]

Generally, the combustion of ethylene–vinyl acetate (EVA) can be effectively suppressed by the incorporation of 50 wt% magnesium hydroxide (MH), but with limited control on matrix dripping and serious deterioration on its mechanical property. In this work, a surface decorated MH by compound silicone resin (CCSi@MH) was prepared and integrated with red phosphorus (RP) introducing into EVA. The EVA/(5%RP + 45%CCSi@MH) composite achieved V-0 rating in the UL 94 test with a limit oxygen index (LOI) of 31%. The dripping behavior was eliminated. Meanwhile, the mechanical properties were ameliorated by CCSi@MH, which was reflected in both static and dynamic mechanical test. The tensile strength and the elongation at break of EVA/(5%RP + 45%CCSi@MH) composite were improved to 3.7 MPa and 52.3%, which were increased by 48% and 41%, respectively, compared with those of EVA/(5%RP + 45%MH) composite. The prepared CCSi@MH provided an accessible method solving the dilemma brought by MH as flame retardant additives in EVA. [ABSTRACT FROM AUTHOR]

A modified kaolinite by grafting with phytic acid (PA‐g‐Kaol) is fabricated, and it was introduced into ethylene vinyl acetate (EVA) with intumescent flame retardancy (IFR) together to improve the flame retardancy of EVA composites. The results show the limiting oxygen index value of EVA/ (18.0 wt% IFR)/ (2.0 wt% PA‐g‐Kaol) is 30.8%. Meanwhile, there is only one dripping produced in the vertical burning test. What's more, the flame‐retardant mechanism is demonstrated by TG‐IR, real‐time‐IR and GC–MS analysis. The results indicate that some pyrolytic products of IFR and PA‐g‐Kaol, like ammonia and phosphoric acid, catalyze the crosslinking of EVA and flame retardant, the resultant compact char protects the substrate from further burning. [ABSTRACT FROM AUTHOR]

For the sake of direct use on the previously constructed wooden buildings, a green flame resistant coating comprising sodium polysilicate (SPS) and boric acid was prepared. With weight gain of only 10 wt%, the treated wood sample (SPS/B-wood) had an improved limiting oxygen index value of 40.3% and passed the V-0 rating in UL-94 test. Additionally, the total heat release, total smoke production and peak carbon monoxide production of SPS/B-wood sample were decreased by 24.5%, 36.0% and 59.4% respectively, compared with that of control wood sample. The residue of SPS/B-wood sample was increased to 54.0% from 18.4% of control wood sample at 800 °C in the thermogravimetric analysis. The flame retardant mechanism suggested that SPS and boric acid formed Si–O–B and Si–O–Si contained structures, isolating the heat and smoke transfer during wood combustion. Notably, NaOH introduced by the SPS/B coating, catalyzed the lignin to form compact and high-quality char. To conclude, this low-cost and easily-applied coating has a promising future in villages where wooden buildings are densely arranged. [ABSTRACT FROM AUTHOR]

Polyethylene terephthalate (PET) fabric has been widely used in textile industry for decades. However, it faces poor flame retardant performance and dripping problem during burning. In our study, a novel intumescent flame retardant coating containing bio‐materials ammonium phytate (APA) and cyclodextrin (CD) had been constructed on PET fabrics surface via pad‐dry‐cure method. The fire performance, mechanical properties and bio‐safety of APA/CD coated fabric were evaluated. PET fabric coated with 19%APA/6%CD showed a limiting oxygen index value of 29.5% with self‐extinguish from fire and no melt dripping during the vertical burning test. Cone calorimetry test revealed that treated PET fabric significantly suppressed heat release and mass loss. The peak heat release rate was decreased from 277.1 KW/m2 of PET fabric to 158.3 KW/m2 of PET‐19%APA/6%CD sample. Furthermore, the residue of treated fabric after combustion was also increased significantly. Tensile strength test showed that the maximum force of fabric was improved by 109.5% in warp direction and 24.2% in weft direction after treatment. Skin irritation test indicated that APA/CD coated PET fabric did not cause erythema and edema to rabbit skin and exhibited satisfactory bio‐safety. All these results suggest that this study proposes a viable way to produce bio‐safety flame retardant PET fabrics. [ABSTRACT FROM AUTHOR]

As a bio‐based and biodegradable textile, poly (lactic acid) (PLA) nonwovens are an important supplement for nature cotton, flax, and silk. This work concentrated on improving the flame retardancy of PLA nonwovens by introducing a novel eco‐friendly flame retardant (TPA), which was synthesized from phytic acid and tris(hydroxymethyl)methyl aminomethane. The structure, composition, and properties of TPA were fully characterized, and the results showed that TPA owned excellent thermal expansion performance. The flame retardancy of PLA nonwovens was efficiently improved by the presence of TPA. For PLA/23%TPA sample, the molten droplet was inhibited and the damaged area was decreased by 71.8%. The LOI value was increased from 18.0% of control PLA to 26.5%, and the peak heat release rate (pHRR) and total heat release rate (THR) were decreased by 30.2% and 29.0%, respectively. Besides, TG analysis confirmed a great char‐forming capability of the treated fabrics with the residue amount increasing from 1.8 to 11.6 wt% at 800°C. TPA released vapor, phosphorus radicals into the gas phase, and also promoted to form a compact char barrier in the condensed phase, which enhanced the carbonization and flame retardancy of PLA nonwovens. To our best knowledge, our work is one of the few studies focused on the flame retardancy of bio‐based PLA nonwovens. [ABSTRACT FROM AUTHOR]

Ammonium polyphosphate (APP) is an effective flame retardant in thermoplastic polyurethane (TPU). In order to further enhance the flame retardant efficiency of APP, it was coated with graphene oxide (GO) and melamine formaldehyde (MF) successively, by using 5 wt% end product of MF‐GO@APP in TPU, the sample produced little dripping during burning and reached UL‐94V‐0 grade, peak smoke production rate was reduced from 0.132 m2/s in TPU to 0.051 m2/s, that was 61.4% decrease. Neat TPU burned out with little residue left, but by the help of 5 wt% MF‐GO@APP, 24.4 wt% of char was left. These results were tried to be analyzed as relative higher heat conductivity of GO, in heating GO transferred more heat to APP and MF, resulting in earlier degradation of APP and MF, the decomposed product of MF and APP cross‐linked together to form more compact char above substrate. MF‐GO@APP acted as an integrated intumescent flame retardant. [ABSTRACT FROM AUTHOR]

Bamboo fibers (BF) were used as charring agent in thermoplastic polyurethane (TPU), together with ammonium polyphosphate (APP) to prepare intumescent flame retardant composites. In order to improve the dispersibility and flame retardant efficiency, BF was grafted with diammonium phosphate (DAP), named as modified bamboo fibers (M‐BF). By the presence of 8 wt% APP and 2 wt% M‐BF, the sample could achieve the maximal limiting oxygen index (LOI) value of 30.5% and V‐0 rating in UL‐94 test. The peak heat release rate for TPU/8APP/2 M‐BF is 190 kW/m2, which is 86.0% lower than that of neat TPU. Besides, TPU/8APP/2 M‐BF sample presented a tensile strength of 23.0 MPa, which was slightly lower than neat TPU sample. The thermogravimetric analysis for TPU composites and the morphology observation of the char demonstrated that APP and M‐BF took effects on condensed phase through promoting the formation of intumescent char structure and free radical trapping. Meanwhile, it could release inert gases in gas phase. Therefore, M‐BF exhibited great potential in applying as renewable charring agent for alleviating the depletion of petroleum resources. [ABSTRACT FROM AUTHOR]

This work reports our recent efforts on the preparation of functionalized multi‐walled carbon nanotubes (f‐CNTs) and its application in improving the fire, conductive, and mechanical performance of epoxy resin (EP) composites in combination with graphite sheets (GSs). The addition of hybrid carbon nanomaterials can effectively improve the mechanical properties of epoxy. Consequently, when the mass fraction of f‐CNTs/GSs is 3.9 wt%, the limiting oxygen index (LOI) value is increased to 27.4%, and the tensile strength and notched impact strength of epoxy are increased by 33.5% and 44.8%, respectively. Increasing the content of carbon nanomaterials can further improve the flame retardancy and electrical conductivity of EP composites. For the sample containing 11.0 wt% f‐CNTs/GSs, the electrical conductivity is further increased to 1.7 × 10−3 S/cm, which can be regarded as conductive materials. The LOI value is reached to 28.6%, with peak heat release and total heat release reduced by 26.4% and 16.4%, respectively. [ABSTRACT FROM AUTHOR]

In order to improve the flame retardancy and antistatic properties of polyamide 6 (PA6) at as low amount of additives as possible, an integrated‐functional additive was synthesized by 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) and multiwalled carbon nanotubes (MWCNTs). The results showed 2 wt% of DOPO‐MWCNTs distributed in PA6 formed an electric network and decreased volume resistivity sharply to 3.1 × 108 Ω cm. In other words, it helped PA6 to get to the percolation threshold of semiconductor. By using of 3 wt% DOPO‐MWCNTs, the severe dripping in burning of PA6 was almost controlled. The possible reason was also ascribed to the network formed by evenly dispersed DOPO‐MWCNTs, which strengthened the char structure and held severe dripping of PA6. As a result, the heat and smoke release were also suppressed obviously. The most important is that CO release was about half cut in CONE test. [ABSTRACT FROM AUTHOR]

Expandable graphite (EG) and modified multi‐wall carbon nanotubes (ATH‐MWNT) were introduced to expandable polystyrene (EPS) foams in order to improve its fire performance. The fire performance of EPS foams was evaluated by limiting the oxygen index (LOI), vertical burning (UL‐94), and cone calorimetry tests. The results showed that the presence of 14.3% EG and 4.1% ATH‐MWNT increased the LOI value from 18.0 to 30.3%, upgraded the UL‐94 rating from no rating to V‐0, completely eliminated melt dripping, and significantly decreased the peak heat release rate from 933 to 177 kW/m2. Thermal analysis indicated that the thermal stability and char formation were improved by the presence of flame retardants. The char morphology was characterized by scanning electronic microscopy (SEM). It was suggested that the presence of EG and ATH‐MWNT could form integrated char layers during combustion, which was beneficial to the formation of an intumescent protective char structure. [ABSTRACT FROM AUTHOR]

Flame retardant expandable polystyrene (EPS) foams were prepared by coating method. Red phosphorus (RP) and expandable graphite (EG) were chosen as the flame retardants to be coated on the surface of expanded PS beads. By the presence of 33 phr RP/EG with a mass ratio of 1:1, the limiting oxygen index of EPS foam could reach up to 26.9%, with V‐0 rating obtained in UL‐94 test. The peak heat release rate could also decrease to 180.67 kW/m2, which was 72.9% lower than that of neat EPS sample. Thermogravimetric analysis revealed an obvious increase of thermal stability and residue char amount by the presence of RP and EG. From the observation and analysis of char residue, it could be proposed that there existed a significant synergistic effect between RP and EG. RP could be oxidized and further react with graphite by the presence of oxygen at high temperature, forming isolated char layer and releasing nonflammable gases. Moreover, P radicals were generated at high temperature and could capture the radicals formed during the combustion of polystyrene and eliminate the burning chain reactions. [ABSTRACT FROM AUTHOR]

Cellulose microcrystalline (CMC), a linear polysaccharide with glucosidic bond, was successfully extracted from bamboo powder and modified by 3‐aminopropyltriethoxy silane coupling agent (KH550) to prepare KH550‐CMC. The prepared KH550‐CMC, in association with ammonium polyphosphate (APP), was introduced into epoxy resin (EP) by casting process to obtain flame retardant composites. The fire performance evaluation indicated that the presence of 10‐phr APP and 5‐phr KH550‐CMC in EP achieved the maximal LOI value of 28.9%, passed the UL‐94 V‐0 rating, and significantly decreased the peak heat release rate from 1055 kW/m2 of neat EP to 286 kW/m2. The improved fire performance is due to the improvement of dispersity of CMC in EP matrix and formation of better char layer, thus protecting the matrix effectively. Moreover, the introduction of KH550‐CMC could also partly eliminate the negative influence of flame retardants on the mechanical properties of EP composites due to the strengthening effect of CMC and better interfacial compatibility after modification with KH550. [ABSTRACT FROM AUTHOR]

A novel intumescent flame retardant (IFR) combination containing ammonium polyphosphate (APP)/p- aminobenzene sulfonic acid modified melamine (AM)/Chitosan (CS) was coated on cotton fabric surfaces via layer-by-layer self-assembly. The fire performance, softness and bio-safety of the treated fabric were evaluated. Fabrics prepared with 15 self-assembly layers of AM-CS/APP had a limiting oxygen index value of 31.5%. Analysis of the cone calorimetry data revealed that the treated fabrics significantly suppressed heat release and mass loss. It was demonstrated that cotton fabrics exhibited a peak heat release rate (pHRR) value of 162.2 kW/m2 and total heat release (THR) value of 17.7 MJ/m2, while the treated fabrics showed pHRR of 98.6 kW/m2 and THR of 7.1 MJ/m2, dropped significant decrease of 40% and 60%, respectively. Furthermore, our results showed that only 8.1 wt% residue remained for the control cotton sample vs. 24.1 wt% for the treated after cone test. Cytotoxicity evaluation indicated bio-safety of the AM modified was much better than that of APP. In addition, the APP/AM/CS coating had minimal negative impact on the mechanical property of the resulting material. These result suggest cotton fabrics treatment proposed in this study provides a feasible way to produce environmentally friendly flame retardant cotton. [ABSTRACT FROM AUTHOR]

Carbon 9 (C9) resin is a major by‐product of the petrochemical industry and is rich in unsaturated hydrocarbons. By copolymerization with maleic anhydride (MAH), the product MAH‐C9 was used as a carbon foaming agent. Combining MAH‐C9 with ammonium polyphosphate (APP), which served as an acid and a gas source, an intumescent flame‐retardant system was introduced into thermoplastic polyurethane (TPU). Flammability evaluation indicated that 4.5 wt% APP and 0.5 wt% MAH‐C9 helped TPU achieve the maximal limiting oxygen index value of 25.9%, passing UL‐94 V‐0 rating. Total smoke release was decreased from 1,884.4 m2/m2 for neat TPU to 833.0 m2/m2 and char formation was promoted. The mechanical loss brought by 5 wt% APP was a little recovered by 4.5 wt% APP/0.5 wt% MAH‐C9. POLYM. ENG. SCI., 60:1029–1034, 2020. © 2020 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Hexakis (4‐aldehyde phenoxy) cyclotriphosphazene (HAPCP) was synthesized firstly and then it was grafted onto the exfoliated kaolinite (Kaol) to prepare K‐HAPCP. The structure of HAPCP and K‐HAPCP was well characterized. K‐HAPCP was used as synergistic agent in poly (butylene succinate) (PBS)/intumescent flame retardants (IFR) composites. The combustion behavior of PBS composites was reflected by limited oxygen index (LOI), vertical burning (UL‐94), and cone calorimeter test. The thermal stability was traced by thermogravimetric analysis. PBS is highly flammable with the LOI value of only 21.9% and cannot pass any UL‐94 grade during vertical burning test. By the presence of 22 wt% IFR and 3 wt% K‐HAPCP, the LOI of PBS composite is sharply increased to 40.3% and the sample can pass UL‐94 V‐0 rating with excellent anti‐dripping properties. Moreover, the degradation behavior is investigated and the probable flame retardant mechanism is also proposed. [ABSTRACT FROM AUTHOR]

Nitrate intercalated hydrotalcite (NO3−‐HTC) was first prepared as precursor; a schiff base derivative containing N, P, and S was synthesized and its structure was characterized. Later the schiff base derivative was used as intercalation to replace NO3− in hydrotalcite. The final product was schiff base derivative intercalated hydrotalcite, which was named as benzaldehyde–taurine–hypophosphorous (BTP)‐HTC. The results showed both NO3−‐HTC and BTP‐HTC can effectively improve the flame retardant and thermostability of ethylene vinyl acetate (EVA). In cone calorimeter test, the peak heat release rate of EVA was 1421.2 kW/m2 and reduced sharply to 746.1/584.5 kW/m2 for 20 wt% NO3−‐HTC/BTP‐HTC adding, respectively. At same time, the total heat release was also decreased from 120.6 MJ/m2 for EVA to 81.0/70.0 MJ/m2, respectively. Morphology observation and composition analysis by scanning electron microscopy (SEM)/X‐ray spectroscopy (EDS) documented the residue left after combustion of EVA/NO3−‐HTC was just ash containing Mg and Al; but for EVA/BTP‐HTC, coherent char layer containing Mg, Al, and P was left. Thermogravimetric analysis indicated that the thermal degradation of EVA was prolonged by either NO3−‐HTC or BTP‐HTC; and char content was kept to 8.6% and 11.0%, respectively. The whole results documented either NO3−‐HTC or BTP‐HTC improved the combustion behavior and thermostability of EVA, and BTP‐HTC showed excellent effect. J. VINYL ADDIT. TECHNOL., 25:255–261, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

In this work, a novel sulfur‐based flame retardant (SA‐M) was synthesized by the self‐assembly of melamine and sulfamic acid. The chemical structure of SA‐M was fully characterized. SA‐M, in company with Al2O3, was then introduced into polyamide 11 (PA 11) by melt compounding in order to improve the fire resistance of the polymer substrate. The observation by scanning electron microscopy (SEM) and electron probe microanalysis (EPMA) indicated the well dispersion of SA‐M in PA 11 matrix. The fire performance of PA 11 composites was evaluated by limiting oxygen index (LOI), vertical burning (UL‐94), and cone calorimeter tests, respectively. The results showed that the presence of 17.5% SA‐M and 2.5% Al2O3 increased the LOI value from 22.4% to 30.9%, upgraded the UL‐94 rating from no rating to V‐0, significantly eliminated the melt dripping, and decreased the peak heat release rate from 1024 to 603 kW/m2. The thermal behaviors were investigated by thermogravimeric analysis (TGA) and TGA‐Fourier transform infrared spectroscopy (FTIR). It was suggested that SA‐M took effects mainly in gas phase by diluting the combustible fuel, leading to the improvement of the fire resistance of PA 11. [ABSTRACT FROM AUTHOR]

Nowadays, numerous works have been undertaken to improve the fire resistance of polylactic acid (PLA). However, the presence of flame retardant usually shows a great destruction on the mechanical properties of PLA matrix, especially the toughness. This paper presents a new approach to simultaneously enhance both the flame retardancy and toughness of PLA by incorporating polyurethane‐microencapsulated ammonium polyphosphate (MCAPP). The prepared MCAPP was blended with PLA by melt compounding to prepare PLA/MCAPP composites. The results indicated that the introduction of 15% MCAPP increased the limiting oxygen index of PLA composites from 19.3% to 28.3%, upgraded the UL‐94 rating from no rating to V‐0, and decreased the peak heat release rate from 464.2 to 332.2 kW/m2. Even though the tensile strength of PLA composites was decreased to 53.8 MPa, the toughness was significantly improved, with elongation at break lengthened to 40.8% and notched impact strength increased to 2.95 kJ/m2. The possible mechanisms for both flame retardancy and toughness were also discussed. POLYM. COMPOS., 40:932–941, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Kaolinite has often been intercalated before being introduced into polymers to improve its dispersibility; however, the conventional intercalation usually reduces the flame retardancy of the composite. This work reports our recent efforts on improving both the flame retardant efficiency and dispersibility of kaolinite in polypropylene (PP) by intercalating with ammonium sulfamate (AS). The intercalation had been performed through three steps: dimethyl sulfoxide was firstly introduced into kaolinite layers under supersonic wave, then it was replaced by potassium acetate-aqueous (KAc), and finally the intercalated KAc was replaced by AS to obtain AS-intercalated kaolinite. The structure of intercalated kaolinite was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy, and thermogravimetric analysis (TGA). The flammability evaluation by limit oxygen index, vertical burning test (UL-94), cone calorimeters test (CONE), and TGA indicated that the fire resistance, thermal stability, and physical properties of PP can be effectively enhanced by the introduction of AS-intercalated kaolinite. The peak heat release rate (pHRR) value of PP composite containing only 1.5 wt% intercalated kaolinite (1169 kW m−2) had been reduced 13.2% compared with that of the sample containing 1.5 wt% raw kaolinite (1346 kW m−2). The morphology analysis from scanning electron microscope images and XRD patterns demonstrated that the compatibility and dispersibility of kaolinite in PP had been significantly improved by intercalation. The flame retardant mechanism of AS-intercalated kaolinite in PP was proposed. [ABSTRACT FROM AUTHOR]

ABSTRACT: In this work, a bio‐based flame retardant, casein, was incorporated into poly(lactic acid) (PLA) matrix by melt compounding in order to improve the fire resistance and sustain the biodegradable character of PLA simultaneously. The fire performance of PLA composites was evaluated by limiting oxygen index, UL‐94 vertical burning, and cone calorimeter tests, respectively. The results indicated that the introduction of 20% casein increased the limiting oxygen index value of PLA composites from 20.0% to 32.2%, upgraded the UL‐94 rating from no rating to V‐0, and decreased the peak heat release rate from 779 to 639 kW/m2. The decomposition products of PLA composites were analyzed by Fourier transform infrared, and the morphology of the char after combustion was observed by scanning electron microscopy. It was suggested that casein took effects in both gas phase by releasing non‐flammable gases (such as NH3 and H2O) and condensed phase by the formation of protective char layers. However, the presence of casein in PLA induced an unavoidable deterioration in the mechanical performance. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46599. [ABSTRACT FROM AUTHOR]

ABSTRACT: Kaolinite (Kaol) and halloysite nanotubes (HNT) are both aluminosilicate clays with similar chemical formulation and different microshapes. In this article, nanotubular HNT and nanoplate Kaol together were introduced into polypropylene (PP) containing intumescent flame retardant (IFR). The flammability of the PP composites was characterized by limiting oxygen index (LOI), vertical burning (UL‐94), and cone calorimeter tests (CCT). The results showed that for the composite with 75 wt % PP and 25 wt % IFR, its LOI was 31.0% and it obtained a UL‐94 grade of V‐2. For the composite of 75 wt % PP, 23.5 wt % IFR, and 1.5 wt % (Kaol/HNT = 9/1), its LOI increased to 36.9 and it obtained a UL‐94 grade of V‐0; at the same time, its peak heat release rate value in CCT decreased by 82.2% compared to neat PP. The thermostability analysis indicated that the mixture of Kaol/HNT could improve the thermostability and final char yield. The char residues were comprehensively analyzed by scanning electron microscopy and Fourier transform infrared spectroscopy. The results illustrated that the Kaol/HNT combination was beneficial to forming a crosslinked network and promoting formation of a compact char with higher strength. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46507. [ABSTRACT FROM AUTHOR]

In this work, a novel single macromolecular intumescent flame retardant (DT-M) was prepared by self-assembly of diethylenetriamine penta-(methylenephosphonic) acid with melamine, and modified layered double hydroxides (LDH) were also prepared by intercalating phytic acid into LDHs. The chemical structures of DT-M and phytic acid intercalated LDHs (PA-LDH) were fully characterized by different analytical instruments, and then were introduced into PLA by melt compounding to prepare a flame retardant biodegradable PLA composite. The fire performance evaluation of PLA composites by limiting oxygen index (LOI), vertical burning (UL-94) and cone calorimeter tests indicated that the introduction of 14% DT-M and 1% PA-LDH increased the LOI value from 19.4 to 38.9%, upgraded the UL-94 rating from no rating to V-0, and decreased the peak heat release rate from 812 to 301 kW m. The analysis for decomposition products of PLA composite and the observation of morphology of the char suggested that DT-M and PA-LDH took effects in both condensed phase through promoting char formation and gas phase through releasing inert gases. [ABSTRACT FROM AUTHOR]

Magnesium hydroxide (MH) was surface modified by bis [3-(triethoxysilyl) propyl] tetrasulfide (Si-69) in order to improve its compatibility with ethylene-vinyl acetate (EVA) copolymer substrate. The modified MH (SMH) was then introduced to EVA through melt blending. The flammability was evaluated by limiting oxygen index (LOI), vertical burning test and cone calorimeter; 40 wt% MH/SMH will lift LOI from 17.9 in EVA to 22.3/23.3, respectively. In cone test, the peak heat release rate (PHRR) of EVA is 1382 kW/m2 and reduced sharply to 601/489 kW/m2 for 40 wt% MH/SMH adding, respectively. The mechanical properties were tested by a drawing machine. The elongation at break dropped almost 7 times by the addition of 40 wt% MH, from 825% in EVA dived to 124%, whereas up to 745% by the addition of 40 wt% SMH. The morphology observation by scanning electron microscopy (SEM) indicated the dispersion of surface modified MH in EVA was remarkably improved than that of MH. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Rutile-type TiO 2 (r-TiO 2 ) or anatase-type TiO 2 (a-TiO 2 ) in association with a conventional intumescent flame retardant system which contains ammonium polyphosphate/pentaerythritol/melamine (APP–PER–MEL) was introduced to silicone-acrylate coatings to improve the fire resistance. The effect of TiO 2 on the fire-resistance and thermal properties of APP–PER–MEL coating has been investigated by using big panel method and thermogravimetry (TG). The limit of fire-resistance of the sample containing 30 phr rutile-type TiO 2 (73 min) is much longer than that of the sample containing 30 phr anatase-type TiO 2 (34 min). The morphology and structure of charring layers were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The relationship between charring process and melt flow rate (MFR) of silicone-acrylate was also discussed. It is suggested that MFR value can significantly affect the formation of char, and a moderate silicone-acrylate MFR is required to form good quality char. [ABSTRACT FROM AUTHOR]

[Display omitted] Despite the advantages of easy moulding and excellent mechanical properties, there are still some shortcomings with polypropylene (PP) such as high flammability and poor ultra-violet (UV) resistance. In this work, modified zinc oxide (mZnO) was prepared by reacting zinc oxide nanoparticles (ZnO) with polysiloxanes, and the effect of mZnO on the effectiveness of intumescent flame-retardant and on the UV aging resistance of polypropylene were investigated. By introducing 16 wt% (intumescent flame-retardant /mZnO) and 0.3 wt% maleic anhydride-grafted PP (MAH-g-PP), the limiting oxygen index increased to 32.7 %, and passed UL-94V-0 rating. In comparison to the controls, the peak heat release rate and the peak smoke release rate were 88.5 % and 80 % lower, respectively. In addition, PP samples showed improved mechanical properties, with a 5 % increase in tensile properties compared to the pure PP sample. After 100 h of UV irradiation, the surface of the samples was relatively flat and smooth, and the carbonyl index decreased from 81.1 of neat PP to 26.7. PP composites with 100 h aging treatment still had excellent flame retardancy and mechanical properties. The results showed that mZnO was effective in improving the flame retardancy, mechanical properties and light aging tolerance of PP. This study provides a novel approach to fabricate long-life flame-retardant PP composites with low additive content. [ABSTRACT FROM AUTHOR]

[Display omitted] Lithium-sulfur batteries (LSBs) have become highly promising next-generation secondary lithium batteries owing to their high theoretical energy density and abundance of sulfur. Nevertheless, the large-scale application of LSBs is still restricted by the shuttle effect of lithium polysulfide (LiPSs) and the potential fire hazard caused by flammable electrolytes. Herein, three electrolyte-insoluble brominated flame retardants (BFRs) are selected and coated on both sides of commercial polypropylene separators by a facile slurry coating method. The effects of the three BFRs on the safety and electrochemical properties of LSBs are characterized and compared. The coating modification separators greatly improves the flame retardancy of LSBs through radical elimination mechanism. The self-extinguishing time of the electrolyte is reduced from 0.66 s/mg to 0.20 s/mg. Moreover, it is demonstrated that the oxygen (O)-containing BFRs exert a significant adsorption capacity and are more advantageous than O-free BFRs in LSBs. In addition, octabromoether (BDDP) coated separator is more effective in trapping LiPSs than decabromodiphenyl ether (DBDPO) due to higher O content, which can mitigate the shuttle effect and enhance the cycle and rate performance of LSBs. This simple coating strategy for separators with BFRs offers a strongly competitive option for the large-scale production of high-safety LSBs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesized a multifunctional reactive additive MX-SP-NH 2 and used it to prepare micro-crosslinked polyurea (PUA) elastomers. • It exhibited superior mechanical properties, compared with reported work. • The fire safety of the PUA was improved, showing significantly reduced heat release, smoke production, and CO production. • We prepared flexible strain sensors based on micro-crosslinked PUA, showing stable electrical signal responsiveness. The widespread application of polyurea (PUA) in protective coatings typically requires excellent flame retardancy due to real-world usage scenarios. However, the addition of flame retardant additives often compromises the material's mechanical properties. In this study, a multifunctional reactive additive, MX-SP-NH 2 , was creatively prepared by covalently grafting spirocyclic pentaerythritol bisphosphorate disphosphoryl chloride (SPDPC) onto MXene (Ti 3 C 2 T x) surfaces, followed by the introduction of 1,3-propanediamine (PDA) by the reaction with SPDPC. MX-SP-NH 2 was then incorporated into PUA, participating in its crosslinking process and significantly enhancing both its mechanical strength and flame retardancy. Compared to the control PUA sample, the micro-crosslinked PUA sample with just 1.0 wt% MX-SP-NH 2 demonstrated a 184.3% increase in tensile strength, a 126.1% increase in elongation at break, and a 436.3% increase in toughness. The flammability characterization revealed that the peak heat release rate, peak smoke production rate, and peak CO production rate were reduced by 31.7%, 28.9%, and 61.5%, respectively, indicating a substantial improvement in fire safety. Additionally, the flame retardant PUA-based flexible strain sensors demonstrated stable electrical signal responsiveness. This work has opened up new potential applications of PUA in flexible electronics. [ABSTRACT FROM AUTHOR]

[Display omitted] • A multifunctional finishing agent AAD is synthesized for PET fabric. • The AAD coating endows PET fabric with excellent flame retardancy and UV resistance. • The AAD coating is recyclable and reusable. Poly (ethylene terephthalate) (PET) fabric is widely used in our lives due to its excellent mechanical strength, high elasticity, wrinkle resistance, and anti-abrasion. However, the inflammability and droplets produced during combustion restricted its application. Herein, a novel PET fabric with fire resistance, anti-dripping, and UV resistance is proposed to resolve this problem. Firstly, the finishing agent (AAD) was synthesized using adipoyl chloride, 9-anthracenemethanol, and diethyl(hydroxymethyl)phosphonate. Then AAD was introduced to the surface of PET fabric by dip-pad-cure process. The limiting oxygen index (LOI) value of AAD-treated PET enhanced to 23.8% from 19.3%. Besides, the fabric passed the vertical burning test (VBT) with no droplets generated. The fabric could still pass the VBT and maintain an LOI value of 23.3% after washing. Meanwhile, the AAD-treated PET fabric showed outstanding UV resistance with a high UPF value of 4318.27. The breaking force of AAD-treated PET was also improved. More importantly, the AAD coating could be easily removed from the fabric using dichloromethane and recycled using a rotary evaporator with a recovery rate of 98.6%. The recycled AAD could also recoated on the PET fabric to impart similar properties. This work proposed a novel strategy to prepare durable flame retardant and UV-resistant PET fabrics with recyclability. [ABSTRACT FROM AUTHOR]

• The trinity monocomponent intumescent flame retardant (IFR) named TAPP was successfully synthesized by microencapsulating the ammonium polyphosphate (APP) with 1, 10-diamino-decane (DA) and tannic acid (TA). • The addition of microencapsulated TAPP significantly enhanced the flame retardancy of polypropylene (PP). • UV resistance of PP composites was also improved due to the introduction of TAPP. Polypropylene (PP) has the advantages of excellent mechanical properties and easy molding, but its shortcomings such as high flammability and poor ultraviolet (UV) resistance cannot be ignored. In this paper, APP was used as the core, 1, 10-diamino-decane (DA) was used as a "bridge" to connect TA to the surface of APP, obtaining TAPP through oxidation self-polymerization. The addition of TAPP greatly improved the flame retardancy and UV resistance of PP matrix. The limiting oxygen index of the PP/22.5 %TAPP sample was increased to 31.0 %, and it was able to pass the UL-94 V-0 rating without droplet produced. Compared with PP samples, the peak heat release rate and peak smoke release rate of PP/22.5 %TAPP sample were reduced by 65.0 % and 44.7 %, respectively. In addition, the tensile strength and impact strength of PP/22.5 %TAPP samples decreased by only 2.7 % and 15.0 % after 60 h UV irradiation. The results showed that the addition of TAPP effectively improved the flame retardancy and UV aging resistance of PP. This study provides a feasible method for the preparation of anti-UV aging and flame-retardant PP composites. [ABSTRACT FROM AUTHOR]

• A phosphorus nitrogen flame retardant (DPVPI) was prepared by successfully grafting flame retardant elements onto PEI using Schiff base reaction. • The addition of DPVPI significantly improves the flame retardant and mechanical properties of epoxy resin. • The dielectric constants of epoxy resin is further reduced, while the transparency performance is preserved. Epoxy resin is widely utilized but faces the drawback of flammability. However, adding flame retardants often results in the compromise of other properties, such as mechanical and optical characteristics. In this study, a phosphorus-nitrogen multifunctional flame retardant named DPVPI was successfully synthesized. The resulting epoxy resin containing DPVPI demonstrated good transparency and low dielectric constant. Furthermore, the unique structure of DPVPI led to additional enhancements in the mechanical properties of EP composite. The tensile strength of EP composite was increased by 33 %, and the impact strength was improved from 13.61 kJ/m² to 25.74 kJ/m². Remarkably, the composites with Only 4wt% DPVPI can achieve a V-0 rating in the UL-94 test and the maximum limiting oxygen index (LOI) of it reached 32.6 %. The cone calorimeter test showed that the peak heat release of the composites with a 5 wt% addition decreased by 35 %, the total smoke release decreased by 37 %, and the char yield doubled. This research presents a novel strategy for subsequent synthesis endeavors about multifunctional flame retardants. [ABSTRACT FROM AUTHOR]

Cotton fabric has extensive application due to its comfort and breathability. However, the inherent flammability limits its wide application. Durable polysaccharide-based flame retardants with a low impact on the softness of fabrics are rarely reported. In this work, a novel flame retardant ammonium phosphate of lentinan (APLNT) was synthesized and grafted on the surface of cotton fabric. The treated cotton fabric had a high limiting oxygen index (LOI) value of 43.3 % and passed the vertical burning test (VBT) with a 21.1 % weight gain of APLNT. Compared with control cotton, the peak heat release rate and total heat release values of Cotton-APLNT 2 decreased by 92.8 % and 50.9 %, respectively. In addition, the cotton fabric still passed the VBT and kept an LOI value of 27.0 % even after 50 laundering cycles, indicating that the fabric can be used for daily needs. More importantly, the treated fabric remains soft. This research provided a new strategy for preparing bio-based durable flame retardant cotton fabrics. [Display omitted] [ABSTRACT FROM AUTHOR]

• The BA-TA-MEL was directly synthesized through a one-pot method without organic solvent. • 5%BA-TA-MEL imparted a desirable UL-94 V-0 rating flame retardancy to PLA. • The incorporation of BA-TA-MEL significantly improved the UV resistance capacity of PLA. • BA-TA-MEL had a reinforcing effect on PLA and improved its mechanical properties. Polylactic acid (PLA), characterized by its biodegradability, easy processing, and environmental friendliness, is regarded as one of the ideal substitutes for petroleum-based polymers. But, the flammability and UV light sensitivity of PLA often impact the safety and service life of its products. In this study, a bio-based additive (BA-TA-MEL) is synthesized via a one-pot method and used as a flame-retardant and anti-UV agent for PLA. The results show that PLA/5%BA-TA-MEL can achieve the desired V-0 degrade in the UL-94 test and an LOI value of 27.1%. Moreover, the PLA/5%BA-TA-MEL exhibits brilliant UV resistance, which increases the UPF to 290.4 from 0.4 of pure PLA. The BA-TA-MEL acts as a rigid particle in the matrix, effectively enhancing the tensile strength of materials. The current work develops a new approach to preparing biodegradable material with excellent performance and extended life to reduce the environmental pressure and pollution caused by petroleum-based plastics. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, a novel bio-based flame retardant LC-PA is prepared by the Mannich reaction between phytic acid (PA) and L-citrulline (LC). LC-PA is combined with tannic acid (TA) and introduced into PLA to improve fire performance and accelerate biodegradability. Compared with control PLA, the PLA composite containing 10% LC-PA/TA increases the LOI value to 26.9%, reaches a V -0 rating in the UL-94 test, and reduces the peak heat release rate and total heat release by 24.5% and 21.1%, respectively. More importantly, the introduction of LC-PA/TA accelerates the degradation rate of PLA in soil, which is of significance for biodegradable materials. The addition of LC-PA/TA can attract water and provide a suitable energy source for microbial proliferation, accelerating the hydrolysis and microbial degradation of PLA. This work provides a practical approach for high flame retardancy and rapid biodegradability in the soil to the bio-based polymer. [Display omitted] • A fully bio-based multifunctional additive (LC-PA/TA) has been synthesized. • 10%LC-PA/TA imparts a desirable flame retardancy to PLA. • LC-PA/TA improves the degradation rate of PLA in the soil. [ABSTRACT FROM AUTHOR]

• Intumescent flame retardant (IFR) and zinc oxide (ZnO) were successfully microencapsulated by polysiloxane. • The addition of microencapsulated IFR and ZnO significantly enhanced the flame retardancy of polypropylene (PP). • Water resistance of PP composites was also enhanced by the presence of microencapsulated IFR and ZnO. Intumescent flame retardant (IFR) and zinc oxide (ZnO) were successfully microencapsulated by polysiloxane, resulting in the preparation of Si-IFR and Si-ZnO, respectively. These microencapsulated additives were then incorporated into polypropylene (PP), leading to a synergistic enhancement of the flame retardancy, mechanical properties, and water resistance. By means of limiting oxygen index (LOI), UL-94 vertical burning test, and cone calorimetry test, an assessment was conducted to analyze the combustion characteristics of PP composite materials containing 2% Si-ZnO and 24% Si-IFR additives. The LOI value and UL-94 of PP/24%Si-IFR/2%Si-ZnO achieved to 39.8% and V-0 rating respectively, with significant decreases in both the total heat release (THR) and total smoke production (TSP). Furthermore, the introduction of polysiloxane significantly improved the water resistance of the PP composites. After a 168-hour water immersion test, notable reductions were observed in water absorption, the precipitation of flame retardants, as well as alterations in the mechanical properties of PP/24%Si-IFR/2%Si-ZnO. [ABSTRACT FROM AUTHOR]

Various polymer substrates have their particular combustion features, therefore, developing an effective universal flame retardant strategy for various polymer substrates is of great practical importance. Meanwhile, as substitutes for petroleum-based products, bio-based flame retardants and biodegradable polylactic acid (PLA) meet the requirements of sustainable development. In this work, a fully bio-based flame retardant coating (PAGS) was prepared using phytic acid (PA) and guanosine (GS). PAGS was used as a universal flame retardant coatings for polylactic acid (PLA) fabrics and other substrates, including cotton fabrics, polyethylene terephthalate (PET) fabrics, polyamide (PA) fabrics, polyurethane (PU) foams, polyethylene terephthalate (PET) films, and woods. The PAGS-treated substrates were able to self-extinguish and eliminate molten droplets. Similarly, the PAGS coating significantly suppressed the heat release of each substrate. The P-containing free radicals in the gas phase were able to interact with highly reactive H , HO and alkyl radicals, blocking the chain reaction during combustion. The flammable gas density was also diluted by nonflammable gases. The formed continuous porous and dense intumescent char layer hindered heat and oxygen. It is suggested that this work provides a simple and efficient flame retardant strategy for improving the fire safety of various polymer substrates. [Display omitted] • An eco-friendly flame retardant coating (PAGS) was prepared. • The PAGS coating was applied on polylactic acid fabrics and other substrates. • The PAGS coating improved the flame retardancy and eliminated molten dripping. • The intumescent flame retardant mechanism of PAGS was proposed. [ABSTRACT FROM AUTHOR]

• By foam finishing with sodium polyborate, cotton fabric obtains good flame retardancy and maintains softness and breathability. • The flame retardant does not involve Cl or P-containing chemicals. • Foam finishing consume lower water or solvent than dip-padding finishing. The conventional process of imparting flame retardancy to cotton fabrics requires the consumption of large amounts of water, chemicals, and energy, which usually involves halogen-containing and phosphorus-containing chemicals. In this work, an eco-friendly sodium polyborate (SPB) foam was creatively introduced onto the cotton fabric surface by a bladed coater to improve the fire resistant performance. For the cotton sample with only 6.7% weight gain (WG) of SPB coating, the LOI value of cotton fabric (SPB treated cotton-1) was enhanced to 32.6% from 18.5%, the damaged length was decreased to 5.7 cm, and the sample self-extinguished in the vertical burning test. The peak of heat release rate value, total heat release value, and total smoke production (TSP) value decreased by 87.0%, 72.7%, and 22.2% respectively compared with those of the control sample. The TSP was further decreased by 80.6% when the WG of SPB was 16.7%. Besides, the SPB treated cotton showed enhanced antibacterial activities against S.aureus and E.coli. Particularly worth mentioning is in the SPB foam finishing procedure, no organic solvent and P or Cl-containing chemicals were involved, and the processing time was only around 3 min with obviously reduced water consumption, compared with dip-padding finishing. More importantly, SPB treated cotton kept good softness, whiteness, water vapor permeability, and air permeability. The SPB foam finishing in this work shows considerable potential in realize good flame retardancy on cotton fabrics by eco-friendly and high-efficient strategy. [ABSTRACT FROM AUTHOR]

• A 3D boron nitride skeleton was fabricated by the ice template method. • The thick skeleton layer provides a more efficient heat transfer path. • The synergistic flame retardant mechanism of boron nitride and ammonium polyphosphate was revealed. • The char residue left in the combustion can support weights more than 1100 times of its own mass. Epoxy (EP) is widely used in the field of high-speed communication and microelectronics. However, its poor thermal conductivity and high flammability bury the hidden danger of fire accident. In this work, the hexagonal born nitride (h-BN) combined with ammonium polyphosphate (APP) constructs a three-dimensional skeleton (3D-BN) via bidirectional freezing technology. The 3D-BN skeleton is immersed into the EP matrix to obtain the EP/3D-BN composite, which is endowed with high thermal conductivity and flame retardancy. When the loading of hexagonal born nitride (h-BN) is 9.1 vol%, the thermal conductivity of EP/3D-BN 3 composite reaches 1.67 W m−1 K−1, which is increased by 944 % compared with that of the control EP. The peak heat release rate (PHRR) and total heat release (THR) of EP/3D-BN 3 are significantly reduced by 54 % and 34 % respectively. This EP/3D-BN composite provides potential applications toward the industrial production for microelectronic devices. In this work, the hexagonal born nitride (h-BN) combined with ammonium polyphosphate (APP) constructs a three-dimensional scaffold (3D-BN) via bidirectional freezing technology. The 3D-BN scaffold is immersed into the epoxy (EP) matrix to obtain the EP/3D-BN composite, which is endowed with high thermal conductivity and flame retardancy. [Display omitted] [ABSTRACT FROM AUTHOR]

Highly transparent polycarbonate (PC) has received more and more attention. However, several key issues, such as its inherent low flame-retardancy and poor scratch-resistance, are still required to be addressed. Herein, a phosphonamide-siloxane (PPA Si) hybrid coating was synthesized and coated on PC plates via sol-gel methods. The combination of PPA and Si endowed PC with excellent fire performance, the formed Si-O-Si cross-linking network provided hardness and curing capacity, and the PPA increased the flexibility of coating. The coated PC sample showed excellent flame retardancy, good scratch resistance, and high transparency. The PC/PPA-Si-3 sample with a limiting oxygen index of 28.5 % achieved a UL-94 V -0 rating. The peak heat release rate and total heat release of the coated sample were decreased by 56.2 % and 18.3 %, respectively, compared to that of the control PC sample. Meanwhile, the pencil hardness was improved from 2B of the control PC to 2H of the PC/PPA-Si-3 sample, and the coating still maintained good flexibility and adhesion even after being immersed in liquid nitrogen for 20 min. Furthermore, the effect of different ratios of phosphonamide and silicon on the flammability and physical mechanical properties of PC was also investigated. This work has offered a possible strategy to produce transparent, flame-retardant, and scratch-resistant PC plates. [Display omitted] • A transparent and flame-retardant coating was prepared via a sol-gel method. • The organic/inorganic hybrid coating improved the surface hardness of PC plates. • The coated PC showed excellent flame retardancy and good flexibility. • The coating layer formed intumescent char during combustion. [ABSTRACT FROM AUTHOR]

• An eco-friendly coating (APP-LA) was prepared based on ammonium polyphosphate (APP) and tyramine (LA). • The APP-LA treated lyocell showed improved flame retardancy. • The possible flame retardant mechanism of APP-LA was proposed. Low-carbon emissions are a sustainable development approach, among which lyocell is a renewable and zero carbon biodegradable cellulose fiber. The flammability of lyocell fabric poses a threat to people's lives and property. In response to this issue, a bio-based flame retardant, tyramine polyphosphate (APP-LA), was synthesized and applied to the treatment of lyocell fabrics. The synthesis of APP-LA adopted an eco-friendly and organic solvent-free method. In the combustion test, the limiting oxygen index of APP-LA treated lyocell fabrics increased to 35.8% compared to control lyocell (18.5%), and the damage length was only 6.7 cm. Meanwhile, the peak heat release rate and total heat release decreased by 92.9% and 58.7% respectively, compared to the control lyocell. Besides, the P-containing compounds generated by APP-LA accelerated the decomposition of the matrix to produce a dense char layer. The fewer flammable volatiles and more non-flammable gases were released. This work provided a low-cost and eco-friendly strategy for the simple preparation of commercial flame-retardant lyocell fabrics. [ABSTRACT FROM AUTHOR]

• A novel DOPO derivative was synthesized and employed as a multi-functional additive for EP. • The EP composite with superior fire-retardancy, mechanical properties and anti-aging performance was obtained. • HP-DOPO shows good compatibility, while accelerate the curing procedure and do not sacrifice the transparency of cured EP. Aiming to develop high performance flame-retardant epoxy resin (EP), a novel phosphorus-containing flame retardant named 6-(3-(2-hydroxyphenyl)propyl)dibenzo-[1,2]oxaphosphinine 6-oxide (HP-DOPO) was synthesized and employed as a multi-functional additive for EP with simultaneously excellent flame retardancy, transmittance, mechanical enhancement and anti-aging. With 5 wt.% loading of HP-DOPO, EP composites showed outstanding flame retardancy with a high limiting oxygen index of 35.6 % and V-0 rating in UL-94 test, while the cone calorimetric test results demonstrated that HP-DOPO could efficiently restrain the heat and smoke release. Compared with pure EP, the resultant EP/5 %HP-DOPO exhibited superior mechanical properties with 27.9 % and 56.2 % increase in tensile and impact strengths, respectively. Furthermore, HP-DOPO accelerated the curing procedure and did not sacrifice the transparency of cured EP, while anti-aging performance was obtained at the same time. The exploration of this novel multi-functional additive provided a powerful basis for the technologies and potential industrial applications of epoxy materials. [ABSTRACT FROM AUTHOR]

Raw kaolinite (kaol) was experimentally transformed to P-type hydrated silica aluminate (HSA-P). After treated by LaCl 3 ·7H 2 O solution, the final product of La-loaded for P-type hydrated silica aluminate (HSA-P-La) was obtained. The middle and final products were characterized using fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM). Kaol, HSA-P, HSA-P-La was introduced into PP with intumescent flame retardants (IFR), respectively. And their effect on the flame retardant and thermal properties of PP composites was studied by limiting oxygen index (LOI), vertical burning test, cone calorimeter test (CCT) and thermogravimetric analysis (TGA). The LOI increases from 18.0% of neat PP to 31.2 in composite of 75 wt% PP/25 wt % IFR, further increases to 32.5, 35.1, 37.5 in 75 wt% PP/23.5 wt % IFR/1.5 wt% Kaol, HSA-P or HSA-P-La, respectively. CCT results show heat release content and rate is best controlled in PP/IFR/HSA-P-La composite. Morphology observation indicates the char layer of PP/IFR/HSA-P-La composite is most compact and thick, which guarantees excellent fire resistance. At same time the effect of HSA-P/HSA-P-La was also compared with generally used A-type hydrated silica aluminate (HSA-A)/HSA-A-La. Anyway HSA-P/HSA-P-La exhibited higher efficiency than HSA-A/HSA-A-La in both flame retardancy and thermostability. [ABSTRACT FROM AUTHOR]

In this paper, a novel flame retardant (ACS) was prepared by crosslinking chitosan with bis-(4-formylphenyl)-phenyl-phosphonate (ABPO). ACS in association with ammonium polyphosphate (APP) and organic modified montmorillonite (OMMT) were used to prepare flame retardant thermoplastic polyurethane (TPU) composite through melt blending. For the TPU sample containing 10% flame retardants, the limiting oxygen index was increased from 20.8 to 29.0%, the vertical burning (UL-94) rating was upgraded from no rating to V-0, and the peak heat release rate was decreased from 1090 to 284 kW/m 2 . The thermal gravity analysis (TGA) indicated that ACS had excellent char formation ability and could greatly enhance the thermal stability of TPU. The tensile strength and elongation at break for flame retardant sample could reach 16.5 MPa and 1443% respectively. [ABSTRACT FROM AUTHOR]

Phosphotungstic acid is a typical kind of superior catalysts, and it is hardly to intercalate into the layered double hydroxides (LDH) by ion-exchange process because of its low negative charge. In this work, a phosphotungstic acid intercalated MgAl-LDH (PWA-LDH) was prepared by reconstruction method, and it was then introduced into poly (lactic acid) (PLA) resin in association with intumescent flame retardant (IFR) by melt blending to prepare a flame-retardant biodegradable PLA composite. The effects of PWA-LDH on the flame retardancy of PLA composites were characterized by limiting oxygen index (LOI), vertical burning test (UL-94) and cone calorimeter test. The results showed that the composite sample containing 18.0 wt% IFR and 2.0 wt% PWA-LDH achieved the maximal LOI value of 48.3%, passed the UL-94 V-0 rating, and significantly decreased the peak heat release rate from 306.3 kW/m 2 of neat PLA to 40.1 kW/m 2 . Thermogravimetric analysis showed that both the thermal stability and the char formation were enhanced. The char morphology observation revealed that PWA-LDH was beneficial to form dense and compact char layers. It was demonstrated that there existed a synergistic effect between IFR and PWA-LDH in promoting the char formation and enhancing the fire resistance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel bio-based nano-flame retardant with core–shell structure (PA-Fe-HBT) are prepared. • PA-Fe-HBT improved the flame retardancy, UV resistance and recyclability of PLA. • The corresponding mechanisms are proposed. Polylactic acid (PLA) is one of the solutions to the white pollution and energy crisis. However, the using performance (such as flame retardant, weather resistance and mechanical properties) and recycling performance limit its wide application. In this work, a bio-based additive (PA-Fe-HBT) with core–shell structure is synthesized by tannins microspheres and phytic acid (PA). By the presence of 3 wt% PA-Fe-HBT, the limited oxygen index is increased to 25.5%, and the sample can pass UL-94 V-0 grade. At the same time, the mechanical properties of the composites remain good. Besides, the ultraviolet aging resistance and ultraviolet protection ability of the composite are significantly improved. The ultraviolet (UV) transmittance of PLA/3%PA-Fe-HBT sample shows a decrease of 99.97% compared with control PLA. More importantly, the chemical recycling of composites is promoted by PA-Fe-HBT in the absence of external heating. After a simple purification, 88% purity of lactic acid is obtained. It is believed that this work proposes an ingenious design strategy to prepare PLA/PA-Fe-HBT composites with flame-retardancy, UV resistance and chemical recycling performances. [ABSTRACT FROM AUTHOR]

It is still a big challenge for textile industry in improving fire resistance and reducing melt dripping with minimal loss on the physical properties of polyethylene terephthalate (PET) fabrics. In this work, a highly-effective hyperbranched flame retardant (DT) was first synthesized by ester exchange without using any organic solvent. Then, the DT foam was prepared and blade coated on PET fabric to improve the fire performance. The prepared PET fabric with only 2.7% weight gain of DT was self-extinguished and did not produce any molten dripping during the vertical flammable test. The peak heat release rate and total heat release of the PET fabric sample with 19.4% DT were decreased by 42.0% and 57.1%, respectively compared with that of the control PET. Besides, the as-prepared PET fabric sample showed better physical properties such as breaking strength, vapor permeability, air permeability, antistatic property, and softness than the control PET fabric sample. The DT foam finishing process did not involve any organic solvent and consumed less water and energy compared with conventional fabric treatments. It is expected that this work provides a facile and eco-friendly strategy for fabricating flame retardant PET fabric with excellent comprehensive performances. [Display omitted] • A hyperbranched flame retardant (DT) was synthesized by a solvent-free approach. • Flame retardant PET fabrics were prepared by sustainable foam finishing. • The PET fabric with 2.7% DT was self-extinguished and free of molten drops. • The treated PET fabric showed excellent physical properties. [ABSTRACT FROM AUTHOR]

• Two reactive flame retardants were obtained through transesterification. • The flame retardants improved the flame retardancy of rigid polyurethane foam. • The mechanical properties and low heat conductivity were well maintained. The reactive type flame retardants have been applied in rigid polyurethane foams (RPUF) owing to their excellent durability and minimal negative effect on the physical properties, however, their flame retardant efficiency cannot meet the requirements in many practical application scenarios. In this work, two reactive-type flame retardants with several hydroxyl groups were synthesized by a solvent-free transesterification between erythritol and dimethyl methyl phosphonate (DMMP), and they were then introduced into RPUF by reacting with isocyanate respectively. The flammability of the as-prepared RPUF samples was evaluated by limiting oxygen index (LOI) and cone calorimeter tests. With the presence of 10 phr as prepared flame retardant, the LOI value of RPUF was improved from 18.3% to 29.8%, and the peak heat release rate (pHRR) and total heat release (THR) were reduced by 31.4% and 47.8% respectively in contrast to that of control RPUF. Furthermore, the compressive strength and thermal conductivity of RPUF containing reactive flame retardants were similar to those of control RPUF. This study provides an innovative method for the clean production of commercial RPUF with fire safety by using a modified phosphorus ester. [ABSTRACT FROM AUTHOR]

[Display omitted] • Formaldehyde-free durable flame-retardant cotton fabrics were prepared. • The fabric had an LOI of 35.3% and was self-extinguishing after 300 washing cycles. • The durability was reinforced by the interface polymerization of PEI and TMC. Due to fire hazards and environmental concerns, considerable attention has been paid to the design of durable flame retardant fabrics. In this work, a formaldehyde-free flame retardant cotton fabric (Cotton-PEI/APP-TMC) with ultra washing durability was prepared via covalent bonding of ammonium polyphosphate (APP) and polyethyleneimine (PEI) followed by the interface polymerization between PEI and trimesoyl chloride (TMC). The prepared fabric exhibited excellent flame retardancy with a limiting oxygen index value (LOI) of 42.0 % and a damaged length of less than 40 mm in the vertical flammability test (VFT). Besides, the cotton-PEI/APP-TMC sample was not ignited in the 50 kW/m2 cone calorimeter test with a dramatic decrease in both the peak heat release rate and total heat release. Even after 300 washing cycles, the cotton-PEI/APP-TMC sample had an LOI value of 35.3 % and was still self-extinguishing in VFT. It was demonstrated that the interface polymerization between PEI and TMC stabilized the flame retardant coating and shielded the Na+ during washing cycles, which endowed the fabric with durable flame retardancy. It is expected this work paves a promising application prospect for the fabrication of bio-safe durable flame retardant cotton fabrics. [ABSTRACT FROM AUTHOR]