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The more efficient and hydrophobic modificated ammonium polyphosphate (M-APP) and charring agent (M-CA) were prepared based on sol–gel method, and they were used in the preparation of water-resistant and flame-retardant polypropylene (PP) composites. The results showed that the contact angles of M-APP and M-CA were 135.11° and 137.89°, respectively. The flame-retardant and thermal properties of the PP composites were also studied. The results showed that the flame retardancy of PP loaded with 30 mass% intumescent flame retardant (M-APP/M-CA = 3:1) was significantly increased. The limiting oxygen index (LOI) reached 36.8% and passed UL-94 V-0. The peak heat release rate and total heat release of the PP composite decreased from 1011.77 to 134.43 kW·m−2 and 100.58 to 6.86 MJ·m−2, respectively. The peak smoke production rate and total smoke release decreased from 0.13 to 0.0056 m2·s−1 and 1453.09 to 74.82 m2·m−2. The PP composite with M-APP/M-CA = 3:1 also exhibited excellent water resistance, and it could still reach UL-94 V-0 after soaking in 70 ℃ water for 168 h. [ABSTRACT FROM AUTHOR]

Fire alarm systems are essential for protecting lives and properties from fire hazards. However, most of the existing fire alarm nanopapers rely on the resistance reduction after heating, which requires direct contact with the flame. In this study, we present a novel fire alarm nanopaper (CMPA) based on heat-triggered shape recovery. The CMPA is composed of hydroxypropyl methyl cellulose (HPMC) as the matrix and 2D nanomaterials M(OH)(OCH 3) as fillers. When the temperature of CMPA exceeded the glass transition, the thrice-folded CMPA-1.0 flattened in 30s and connected to the alarm circuit based on its conductive surface. According to the results, the CMPA-1.0 with a thickness of about 0.2 mm had an efficient electromagnetic shielding of 42.1 dB. Moreover, the CMPA-1.0 self-extinguished rapidly after being ignited with its original shape preserved. The peak heat release rate of CMPA-1.0 was 108.9 W/g, which was 61.9 % lower than that of HPMC. Furthermore, the thermal conductivity of CMPA-1.0 reached to 0.317 W m−1 K−1, which was 40.8 % higher than that of HPMC, reducing the heat accumulation effectively. This work shows that CMPA is an ideal material for sensitive and safe early fire alarm, and the strategy based on heat-triggered shape recovery is promising in fire alarm application. [ABSTRACT FROM AUTHOR]

Phosphorylated celluloses (PCFs) were obtained via reaction of microcrystalline cellulose with phosphorous acid in molten urea. Fourier transform infrared spectroscopy and scanning electron microscopy were used to observe the chemical structure and microstate of the PCFs. A flame retardant glutaraldehyde cross‐linked poly (vinyl alcohol)/PCF aerogel was fabricated using a melt cross‐link and freeze‐dried method. The results of thermogravimetric analysis confirmed that the thermal stability of the poly(vinyl alcohol) (PVA) aerogels incorporating PCF is more outstanding. The peak of heat release rate (PHRR) and the total heat release (THR) values of the PCA/PCF10 aerogel deceased obviously by 33.8 and 64%, respectively, compared to the corresponding values for the pure PVA aerogel; these changes confirm that the PCA/PCF aerogel had better flame‐retardant properties than the pure PVA aerogel. Moreover, the fire performance index and fire growth index indicate that the introduction of PCF would diminish the occurrence of fire. [ABSTRACT FROM AUTHOR]

Summary: Wheat straw (WS) has numerous advantages compared with traditional bioadditives such as starch and lignin. So in this work, based on WS and silica microencapsulated ammonium polyphosphate, flame retardant polypropylene/wheat straw (WSP) composites were prepared by melted blend method. Flame retardant and thermal properties of WSP composites have been investigated. The results of cone calorimeter show that peaks of heat release rate and total heat release of the flame retardant WSP composite decrease substantially compared with those of pure polypropylene. The peak of heat release rate value of the flame retardant WSP composite decreases from 1290.5 to 247.9 kW/m2, and the total heat release value decreases from 119.4 to 46.3 MJ/m2. Meanwhile, thermal degradation and gas products of the flame retardant WSP composite were monitored by thermogravimetric analysis and thermogravimetric analysis‐infrared spectrometry. The result of thermal analysis shows that the flame retardant WSP composite has a high thermal stability and has a 30.0 wt% residual char at 600°C. From this work, we hope to provide a method to prepare flame retardant polymer composites with a biodegradable natural material‐WS. [ABSTRACT FROM AUTHOR]

In this study, the two-dimensional bimetallic nanosheets, M(OH)(OCH 3) (M = Co, Ni) was used as a novel "nano-flame retardant" to improving fire retardancy and smoke suppression of epoxy resin (EP) nanocomposties. With 3 wt% M(OH)(OCH 3) added, the peak heat release of EP/M(OH)(OCH 3)-3 wt% decreased from 1021.4 to 867.8 kW/m2, compared with pure EP. To the smoke suppression, the peak of smoke product rate and the total smoke product of EP/M(OH)(OCH 3)-3 wt% was 0.27 m2/s and 28.3 m2, which decreases by 15.6 and 15.0% than those of pure EP, respectively. Only 1 wt% M(OH)(OCH 3)@Ni, which got the modification by the introduction of nickel ion on surface, could endow the composite a further improvement in both flame retardant and smoke suppression. The results of gas chromatography-mass spectrometer demonstrated the M(OH)(OCH 3)@Ni facilitated the aromatization reaction and promotes the generation of the protective char layer, which hinders the propagation of combustible free radicals and restrains the release of smoke. This study demonstrated that the two-dimensional bimetallic nanosheets, M(OH)(OCH 3) (M = Co, Ni), has a great potential to act as novel "nano flame retardant". Moreover, the appropriate modification could further promote its performance in improving the flame ratardancy and smoke suppression of EP. • M(OH)(OCH 3)(M = Co, Ni) was used as a novel "nano-flame retardant" to fabricate flame retardant and smoke suppression EP. • 3 wt% M(OH)(OCH 3) could efficiently enhance the flame retardant and smoke suppression of EP composites. • 1 wt% M(OH)(OCH 3)@Ni realize a further promotion in flame retardant and smoke suppression of EP. • Aromatization reaction has been confirmed as the effective mechanism of flame retardant and smoke suppression. [ABSTRACT FROM AUTHOR]

A novel bio-flame retardant (PA-B) was prepared based on green materials--banana peel powder (BPP) and phytic acid (PA), then PA-B was used to prepare flame retardant poly(lactic acid) (PLA) composites. The flame retardancy and thermal property of PLA composites were studied. It can be found that the limiting oxygen index (LOI) of PLA composite with 15.0 wt% BPP is 22.1%, showing the heavy dripping during the combustion and failing to reach the vertical burning tests (UL-94) V-0 rating. However, when 15.0 wt% PA-B is added, the LOI is significantly increased to 37.5%, and the composite can reach UL-94 V-0 rating with the dripping problem is obviously reduced. Furthermore, PA-B is helpful to ameliorate the thermal property of PLA composites under the high temperature. The char residue of PLA/PA-B15 is 10.9 wt% at 550.0 °C, showing much higher value than that of PLA/B15 (3.3 wt%) and pure PLA (almost nothing left). From flammability analysis, PA-B not only is a crucial part of promoting the formation of char layer with high quality in the solid phase, which can play a "barrier effect" role to protect the underlying matrix and retard combustion process, but also has the flame retardant effect in the gaseous phase on the basis of PO· free radical. This work provides an efficient way to prepare bio-based flame retardant PLA composites, and also offers a new method to reuse agricultural wastes like banana peel. [ABSTRACT FROM AUTHOR]