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Melamine–formaldehyde resin-coated bamboo fiber (MFBF) and ammonium polyphosphate (MFAPP) were prepared, and then flame-retardant polypropylene (PP)/bamboo fiber composites based on MFBF/MFAPP were obtained by melt blending. The water resistance, flame retardant, and thermal properties of the composites were studied. The results show that MFBF and MFAPP have excellent water resistance with the water contact angles 130.85° and 119.78°, respectively. Compared with pure PP, the limit oxygen index (LOI) of the prepared composite increased from 18.5 to 25.5% with the UL-94V-0 rating. The peak heat release rate of the composite decreased from 1011.8 to 344.3 kW·m−2 and the total heat release decreased from 100.6 to 58.8 MJ·m−2. Meanwhile, the total smoke release decreased from 1453.3 to 922.0 m2·m−2. After soaking in 70 °C water for 36 h, the composite still reached the V-0 rating in UL-94 test, demonstrating a good water resistance. This work provides an effective method to improve the water resistance and flame retardancy of PP/bamboo fiber composites. Melamine–formaldehyde resin-coated bamboo fibers (MFBF) and ammonium polyphosphate (MFAPP) were prepared, then flame-retardant PP/BF composites were obtained based on MFBF/MFAPP. The results show that prepared composite exhibited excellent water resistance and flame-retardant properties. [ABSTRACT FROM AUTHOR]

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]

Rigid polyurethane foam/aluminum diethylphosphinate (RUPF/ADP) composites were prepared by one-step water-blown method. Furthermore, scanning electron microscope (SEM), thermal conductivity meter, thermogravimetric analysis (TGA), limiting oxygen index, Underwriters Laboratories vertical burning test (UL-94) and microsacle combustion calorimetry were applied to investigate thermal conductivity, thermal stability, flame retardancy and combustion behavior of RPUF/ADP composites. Thermogravimetric analysis–Fourier transform infrared spectroscopy (TG–FTIR) was introduced to investigate gaseous products in degradation process of RPUF/ADP composites, while SEM and X-ray photoelectron spectroscopy were used to research char residue of the composites. It was confirmed that RPUF/ADP composites presented well cell structure with density of 53.1–59.0 kg m−3 and thermal conductivity of 0.0425–0.0468 W m−1 K−1, indicating excellent insulation performance of the composites. Flame retardant test showed that ADP significantly enhanced flame retardancy of RPUF/ADP composites, RPUF/ADP30 passed UL-94 V-1 rating with LOI of 23.0 vol%. MCC test showed that ADP could significantly decrease peak of heat release rate (PHPR) of RPUF/ADP composites. PHPR value of RPUF/ADP20 was decreased to 158 W g−1, which was 21.8% reduced compared with that of pure RPUF. TG–FTIR test revealed that the addition of ADP promoted the release of CO2, hydrocarbons and isocyanate compound in first-step degradation of RPUF matrix while inhibited the release of CO in second step degradation. Char residue analysis showed that the addition of ADP promoted polyurethane molecular chain to form aromatic and aromatic heterocyclic structure, enhancing strength and compactness of the char. This work associated a gas–solid flame retardancy mechanism with the incorporation of ADP, which presented an effective strategy for preparation of flame retardant RPUF composites. [ABSTRACT FROM AUTHOR]

Flame-retardant glass fiber-reinforced PA6 (GFPA6) composites were prepared by incorporating the mixture of piperazine pyrophosphate (PAPP) and aluminum hypophosphite (AHP) into GFPA6. From the results of UL-94 test, limiting oxygen index (LOI) and microscale combustion calorimetry (MCC) tests, the as-obtained composites exhibited significantly enhanced flame retardancy including higher LOI values, better UL94 rating (V-0 for 18.0 mass% PAPP/AHP mixture), and decreased peak heat release rate and total heat release. And PA6-4 with a 4/1 mass ratio of PAPP to AHP reached the highest LOI value. The influence of PAPP/AHP on the decomposition pathway of GFPA6 was discussed based on TG and TG-FTIR analysis. The interaction between PAPP/AHP and GFPA6 altered the decomposition pathway of GFPA6 resulting in the formation of compact char layer, high thermal stability within high-temperature region, and weak intensities of a variety of pyrolysis gas products. Meanwhile, the thermomechanical property data revealed the storage modulus of samples were increased with increasing PAPP/AHP content, whereas the glass transition temperatures were reduced gradually. Moreover, the results of scanning electron microscope illustrated that the introduction of PAPP/AHP mixture can promote the formation of compact char layer and change the surface element composition of the char. [ABSTRACT FROM AUTHOR]

A new series of four different linear aliphatic ether linked aromatic bismaleimides (AEBMIs) were synthesized from the respective linear aliphatic ether-linked aromatic diamines and maleic anhydride. Further, the POSS-AEBMI nanocomposites were developed by Michael addition reaction of bismaleimide with varying mass percentages of octa(aminophenyl)silsesquioxane and were characterized by the fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. Data from thermal studies revealed that the POSS-reinforced AEBMI nanocomposites possesses higher glass transition temperature ( Tg), thermal stability, limiting oxygen index, and lower dielectric constant when compare to that of neat AEBMI. X-ray diffraction and transmission electron microscopy analysis confirmed the molecular level dispersion of POSS in the AEBMI matrix. [ABSTRACT FROM AUTHOR]