Influence of aging conditions on the mechanical properties and flame retardancy of HIPS composites

In this study, we evaluate the changes in physical properties and flame retardancy of HIPS composites after natural aging tests in Turpan (high sunlight radiation dose and dry) and Qionghai (high temperature and rainy) in China for 21 months. The HIPS composite aged in Turpan revealed a higher chromatic aberration than that in Qionghai due to the higher sunlight radiation dose. After aging tests for 21 months, the mechanical properties and the peak heat release of the HIPS composite aged in Qionghai decreased by more than 50% and increased by 39.7%, respectively, results that were worse than for the HIPS composite in aged Turpan. This was related to the combined effects of light, temperature, rain, and moisture in Qionghai leading to more severe degradation of HIPS composites, which results in breaking of the polymer chains and migration and erosion of the flame retardant. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46339.     

A facile one‐step synthesis of flame‐retardant coatings on cotton fabric via ultrasound irradiation

This article reports a facile one‐step methodology to increase fire resistance properties of cotton fabric. The flame‐retardant coating for cotton fabric was synthesized with methyltriethoxysilane and organophosphates (M102B) through an ultrasound irradiation process. The coating structure and surface morphology of uncoated and coated fabrics were investigated by Fourier transform infrared spectroscopy and scanning electron microscope, respectively. The flame‐retardant properties, bending modulus, air permeability and thermal stability were studied by vertical burning test, cantilever method, air permeability test and thermogravimetric analysis (TGA). As a result, the cotton fabric coated with 29.2% (mass increased) of flame‐retardant coating was able to balance the flame retardant property and wearing comfort of the fabrics. The TGA results showed that the residue char of cotton was greatly enhanced after treatment with the coating, which has a high char forming effect on cellulose during testing. Furthermore, flame‐retardant property of coated fabrics did not change significantly after 10 washing cycles. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45114.     

Durable flame‐retardant and antidroplet finishing of polyester fabrics with flexible polysiloxane and phytic acid through layer‐by‐layer assembly and sol–gel process

A three‐layer functional coating was prepared through layer‐by‐layer (LbL) assembly and a sol–gel process. The multilayered coating was composed of a phytic acid (PA) coating dipped between two layers of flexible polysiloxane coatings and was deposited on the polyester fabric by LbL assembly. Flammability tests indicated that the multilayer coating prevented droplet generation during combustion. The PA also absorbed the reactive free radicals to reduce the flame‐burning rate. After being soaked for only 20 min in PA solution, the fabric exhibited self‐extinguishing properties and antidroplet effect during the vertical flame test, while cone calorimetry confirmed that the coated fabric exhibited a 65% decrease in the peak heat release rate and reduced the total amount of smoke released by 72%. After washing the coated fabric 45 times, there was no significant decrease in the phosphorus content and the limiting oxygen index of coated fabrics. Thus, the coating synthesized in this study is an effective method of constructing durable, functional coatings on the surface of fabrics. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46414.     

Influence of gamma radiation on compatibilized LLDPE/magnesium hydroxide/sepiolite composites

The influence of gamma irradiation on the properties of compatibilized linear low‐density polyethylene/magnesium hydroxide (MH)/sepiolite composites has been investigated. Vinyl triethoxy silane and maleated polyethylene have been used as compatibilizers. The compatibilizing effect in the composites is confirmed by the Fourier transform infrared spectra, which showed the presence of additional chemical bonds, which are responsible for the enhanced polymer‐filler interaction. As a result, the miscibility of the polar additives into the nonpolar polymer matrix is enhanced. The scanning electron micrographs revealed that the additives are well embedded and uniformly dispersed in the polymer matrix without any voids. The known thermal decomposition temperature of MH (～ 350°C) is also increased in the compatibilized composites. In addition, 150 kGy irradiated composite showed a remarkable improvement of 37°C in the onset degradation temperature of unirradiated composite. Furthermore, the formation of radiation crosslinked structure in the composites also improved the mechanical properties of the composites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Influence of the surface modification of a filler on the properties of high‐impact polystyrene composites

A novel technique of surface modification was used to treat nanomodified aluminum trihydrate (nano‐CG‐ATH). The results of the surface modification were characterized with transmission electron microscopy and Fourier transform infrared spectra. The effects of the surface modification on the properties of high‐impact polystyrene (HIPS) composites were studied with limiting oxygen index (LOI) and mechanical tests. The dispersion of nano‐CG‐ATH in the HIPS matrix and the interfacial adhesion between them were observed with transmission electron microscopy and scanning electron microscopy. The experimental results demonstrate that the surface of nano‐CG‐ATH was successfully grafted by an organic substance, and the dispersion of treated nano‐CG‐ATH in ethanol was better than that of untreated nano‐CG‐ATH. At high loadings, the mechanical properties and LOI values of the HIPS composites with treated nano‐CG‐ATH were higher than those of the HIPS composites with untreated nano‐CG‐ATH. The dispersion of treated nano‐CG‐ATH in the HIPS matrix was better than that of untreated nano‐CG‐ATH in the HIPS matrix. Also, the interfacial adhesion between the HIPS matrix and treated nano‐CG‐ATH was better than that between the HIPS matrix and untreated nano‐CG‐ATH. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and properties of nadic‐end‐capped cyclotriphosphazene‐containing polyimide/carbon fiber composites

New novel fire‐resistant and heat‐resistant cyclotriphosphazene‐containing polyimide resins were prepared in situ by the polymerization of (p‐aminophenoxy)(phenoxy)cyclotriphosphazenes with 3,3′,4,4′‐benzophenonetetracarboxylic acid or 3,3′,4,4′‐diphenylsulfonetetracarboxylic acid and a crosslink agent, 5‐norbornene‐2,3‐dicarboxylic acid and were used as polymer matrix compositing with a woven carbon fiber to prepare nadic‐end‐capped cyclotriphosphazene‐containing polyimide/carbon fiber composites. The thermal stability, flame retardance, morphology of the surface fracture, and some physical properties of the composites were investigated by thermogravimetric analysis, scanning electron microscopy, and a material testing system, respectively. The composites had good thermal stability, flame retardance, and mechanical properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 810–818, 2003     

Kinetic study on the synergistic effect between molecular weight and phosphorus content of flame retardant copolyesters in solid-state polymerization

2-Carboxyethyl(phenyl phosphinic) acid has been proved to modify flame retardant properties of poly(ethylene terephthalate) (PET) through copolymerization; however, there is no industrial technological breakthroughs in polyester industrial yarns which requires high strength and modulus, because it is related to the coordinated control of molecular weight and flame retardancy. In this work, the influence of solid-state polymerization reaction kinetics and parameters on flame retardancy retention have been investigated, based on the prepared precursors optimized at 6,000 ppm phosphorus content and 0.64 dL/g intrinsic viscosity (I.V). Results showed that the copolyester polydispersity index increase was significant compared to PET with molecular weight increase. The I.V of optimized precursor could be increased to 1.31 dL/g at 220°C in 20 hr, but at higher phosphorus content loses up to 7%. Flame retardant component deteriorates with increasing reaction rate and temperature as a result of severe side reactions. Optimized precursor at the optimum temperature (210°C) reacted for 20 hr, copolyester with the phosphorus content of 5,910 ppm and the I.V of 1.12 dL/g (( was about 3.5 × 10⁴ g/mol) was prepared. The coordination between high molecular weight and flame retardant performance was realized.     

Preparation of novel dendritic flame‐retardant polymer and its application in EPDM composites

Flame‐retardant polymer, dendritic tetramethylolphosphonium chloride (FR‐DTHPC), was prepared by condensation polymerization between THPC, the monomer we prepared, and boric acid. It was then characterized by Fourier transform infrared spectroscopy, intrinsic viscosity, and matrix assisted laser desorption ionization time of flight mass spectrometer. This FR‐DTHPC was used in the preparation of flame‐retardant ethylene propylene diene monomer (EPDM) composites. Different types of EPDM/FR‐DTHPC composites were prepared with different amounts of FR‐DTHPC. Then, the cure characteristic, tensile properties, flame‐retardance, and thermal stability were researched and compared. Results showed that the addition of this novel additive can improve some mechanical and flame‐retardant properties of EPDM composites. Mechanisms of reinforcing and flame‐retardance were proposed. The dendritic polymer may reduce the amount and size of voids in EPDM composites, and thus may increase their tensile properties. Meanwhile, the degradation products from nitrogen, phosphorus, and boric acid in FR‐DTHPC can increase the amount of carbonaceous layers, and thus can inhibit the pyrolysis degree of EPDM composites during burning and improve their flame‐retardant performance. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40855.     

Influence of fumed silica on the flame‐retardant properties of ethylene vinyl acetate/aluminum hydroxide composites

The flammability and synergistic flame‐retardant effects of fumed silica (SiO₂) in ethylene vinyl acetate (EVA)/aluminum hydroxide (ATH) blends were studied with limiting oxygen index measurements, UL 94 testing, cone calorimeter testing (CONE), and thermogravimetric analysis (TGA). The results show that the addition of a given amount of fumed SiO₂ can apparently improve UL 94 rating. The CONE data indicated that the addition of fumed SiO₂ greatly reduced the heat release rate. The TGA data showed that this synergistic flame‐retardant mechanism of fumed SiO₂ in the EVA/ATH materials was mainly due to the physical process. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of chicken‐feather protein‐based flame retardant on flame retarding performance of cotton fabric

A new kind of eco‐friendly chicken‐feather protein‐based phosphorus–nitrogen‐containing flame retardant was synthesized successfully with chicken‐feather protein, melamine, sodium pyrophosphate, and glyoxal. And its structure was characterized by Fourier transform infrared spectroscopy, and the thermogravimetry of the agent was analyzed. Then the flame retarding performances of the chicken‐feather protein‐based flame retardant and in combination with the borax and boric acid in application to a woven cotton fabric were investigated by the vertical flammability test and limited oxygen index test. In addition, the surface morphologies of the treated and untreated fabrics were conducted by the scanning electron micrographs (SEM), and the thermogravimetric analyses of the treated and untreated cotton were explored, and the surface morphologies of char areas of the treated and untreated fabrics after burnt were tested by the SEM. The results showed that the flame retardancy of the cotton fabric treated by the chicken‐feather protein‐based flame retardant in combination with borax and boric acid was improved further, and the combination of the chicken‐feather protein‐based flame retardant and borax and boric acid could facilitate to form a homogenous and compact intumescing char layer, and the combination of them plays a good synergistic effect in the improvement of the flame retardancy of the treated cotton fabric. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40584.     

双邻苯二甲腈改性环氧及其玻纤复合材料制备

采用双邻苯二甲腈树脂(BAPh)对环氧树脂E-44(EP)进行改性,同时制备了BAPh/EP/玻纤复合材料。采用示差扫描量热仪,热重分析,力学性能测试及氧指数仪研究了改性树脂的热性能、力学性能及阻燃性能,并对BAPh/EP/玻纤复合材料的力学性能进行了表征。结果表明,当BAPh质量分数达到50%时,改性树脂固化物在空气中的起始分解温度达到377.6℃,比纯环氧提高74.3℃,氧指数达到34.5%,复合材料的弯曲性能指标达到最大,添加双邻苯二甲腈后环氧树脂的耐热性、力学性能和阻燃性能得到了明显改善。     

Flame retardance and origin of bismaleimide resin composites with green and efficient aluminum phosphates

Developing green and high efficiency inorganic flame retardants is the trend of preparing flame retarding polymer composites. Aluminum phosphates (t‐hAP) with uniform, small dimension, and hexagonal structure were facilely synthesized, which have similar size (1–2 μm) but different structures from commercial spherical‐like aluminum phosphate (cAP). The flame retardance of bismaleimide (BD)/t‐hAP and BD/cAP composites were intensively investigated. t‐hAP is proved to have much better flame retarding effect than cAP, but also exhibits advantages over Mg(OH)₂ and Al(OH)₃. With only 5 wt % addition of t‐hAP into BD resin, the peak and total heat releases as well as total smoke production significantly reduce 42.3, 47.8, and 67.3%, respectively; besides, better data are obtained as the loading of t‐hAP increases to 10 wt %. These attractive data result from three effects induced by t‐hAP. Besides the better protection role of sheet structure, the strong hydrogen bonding between t‐hAP and BD resin endows the composite with good dispersion of t‐hAP and high crosslinking density; moreover, t‐hAP releases H₂O and NH₃, diluting flammable gases during combustion. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41089.     

Improvement of flame retardancy in phenolics and paper-sludge/phenolic composites

Paper-sludge/phenolic composites were fabricated using a novolac-type phenolic resin and paper sludge. A phosphate flame retardant containing halogen (tris 2-chloroethyl phosphate) and inorganic flame retardant (aluminum trihydroxide) were introduced into neat phenolics and paper-sludge/phenolic composite in order to improve their flame retardancy. In addition, magnesium hydroxide and halogenated flame retardant were added into the paper-sludge/phenolic composite. The flame retardancies were estimated with the UL 94 test. To study the flame retardant mechanism, thermal analysis of the phenolics and the paper-sludge/phenolic composites were carried out using a thermogravimetric analyzer and a differential scanning calorimeter. The phosphated flame retardant and inorganic flame retardant both showed the flame retardant effect on the phenolics. However, the flame retardancy of the paper-sludge/phenolic composite was enhanced only by phosphated and halogenated flame retardants. This result is attributed to the fact that the flame retardancies of the phenolics and paper-sludge/phenolic composite depend on their heat capacities and decomposition behaviors. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2043–2050, 1998     

Effect of a type of triazine on the properties and morphologies of poly(butylene terephthalate) composites

Composites of poly(butylene terephthalate) (PBT), 2,4,6‐tris(2′,4′,6′‐tribromophenoxy)‐1,3,5‐triazine (TTA), and glass fibers were prepared, and the effect of TTA on the properties and morphologies of the composites was studied. The results showed that the addition of a suitable amount of TTA could improve the flame retardancy of PBT composites reinforced with glass fibers, and good resistance to TTA emigration from the inside of the composites onto their surfaces was obtained. Fourier transform infrared spectroscopy analyses of PBT, TTA, and their blend suggested that there might be no chemical bonds formed on the interfaces between PBT and TTA in the composite; a thermogravimetric study revealed that the weight loss of the PBT/TTA composite was very limited in the temperature range of 25–300°C, and scanning electron microscopy images of the blend demonstrated that the TTA particle sizes and their distribution in the PBT matrix remained thermally stable when the system was heated at 130°C for 3 h. This suggested good compatibility of TTA with PBT. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1291–1296, 2006     

Cross-linked Salen-based polyphosphazenes (Salen-PZNs) enhancing the fire resistance of epoxy resin composites

In this work, two cross-linked Salen-based polyphosphazenes (Salen-PZNs: Salen-PZN-1 microspheres and layered Salen-PZN-2), which contains Salen-Schiff base and phosphazene components, were synthesized. The results showed that the peak heat release rate and total smoke production of 3% Salen-PZN-1/epoxy resin (EP) (3 wt% addition) were reduced by 23.8% and 87.3%, respectively. Meanwhile, after introducing the layered Salen-PZN-2 into EP, efficient flame resistance was obtained. The results of thermogravimetric analysis/infrared spectrometry proved that the harmful gasses of 5% Salen-PZN-1/EP composites were reduced during the combustion. The possible flame retardancy mechanism was considered to be the synergy of phosphate group catalysis, release of nitrogen-containing noncombustible gasses and gas phase quenching. Therefore, this work provides a method for preparing polymers with highly efficient flame-retardant properties.     

Component ratio effects of hyperbranched triazine compound and ammonium polyphosphate in flame‐retardant polypropylene composites

A hyperbranched derivative of triazine group (EA) was synthesized by elimination reaction between ethylenediamine and cyanuric chloride. The different‐mass‐ratio EA and ammonium polyphosphate (APP) were mixed and blended with polypropylene (PP) in a constant amount (25%) to prepare a series of EA/APP/PP composites. The component ratio effect of EA/APP on the flame‐retardant property of the EA/APP/PP composites was investigated using the limiting oxygen index (LOI), vertical burning (UL‐94), and cone calorimetry tests. Results indicated that the EA/APP/PP (7.50/17.50/75.00) composite with the appropriate EA/APP mass ratio had the highest LOI, UL94 V‐0 rating, lowest heat release rate, and highest residue yield. These results implied that the appropriate EA/APP mass ratio formed a better intumescent flame‐retardant system and adequately exerted their synergistic effects. Furthermore, average effective combustion heat values revealed that EA/APP flame retardant possessed the gaseous‐phase flame‐retardant effect on PP. Residues of the EA/APP/PP composites were also investigated by scanning electron microscopy, Fourier‐transform infrared, and X‐ray photoelectron spectroscopy. Results demonstrated that the appropriate EA/APP mass ratio can fully interact and lock more chemical constituents containing carbon and nitrogen in the residue, thereby resulting in the formation of a dense, compact, and intumescent char layer. This char layer exerted a condensed‐phase flame‐retardant effect on EA/APP/PP composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41006.     

Preparation and thermal analysis of cotton–clay nanocomposites

Nanocomposites were produced from cotton with montmorillonite clay used as the nanofiller material. Three exfoliation and intercalation methods with different solvents and clay pretreatment techniques were tested for the production of these organic–inorganic hybrids. The method that resulted in superior clay–cotton nanocomposites used a clay pretreatment with 4‐methylmorpholine‐N‐oxide as the cotton solvent. The nanocomposites showed significant improvements in the thermal properties in comparison with unbleached cotton and cotton processed under the conditions for nanocomposite preparation. The degradation temperature of the nanocomposites increased by 45°C, and the char yields for some compositions were twice those of unbleached cotton. The crystalline melt of the materials decreased by 15°C. Future research will include the development of textiles based on these cotton–clay materials and testing for flame‐retardant properties and product strength. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2125–2131, 2004     

Epoxy resin/phosphorus‐based microcapsules: Their synergistic effect on flame retardation properties of high‐density polyethylene/graphene nanoplatelets composites

Two types of microcapsule flame retardants are prepared by coating ammonium polyphosphate (APP) and aluminum diethylphosphinate (ADP) with epoxy resin (EP) as the shell via in situ polymerization, and blended with high density polyethylene (HDPE)/graphene nanoplatelets (GNPs) composites to obtain flame‐retardant HDPE materials. Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), and water contact angle results confirm the formation of core–shell structures of EP@APP and EP@ADP. The limiting oxygen index (LOI), vertical burning test (UL‐94), cone calorimetry, and Raman spectroscopy are employed to characterize the HDPE/GNPs composites filled with EP@APP and EP@ADP core–shell materials. A UL94 V‐0 level and LOI of 34% is achieved, and the two flame retardants incorporated in the HDPE/GNPs composite at 20 wt % in total play a synergistic effect in the flame retardancy of the composite at a mass ratio of EP@ADP:EP@APP = 2:1. According to the cone‐calorimetric data, the compounding composites present much lower peak heat release rate (300 kW/m²) and total heat release (99.4 MJ/m²) than those of pure HDPE. Raman spectroscopic analysis of the composites after combustion reveals that the degree of graphitization of the residual char can reach 2.31, indicating the remarkable flame retarding property of the composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46662.     

Synthesis of a melamine‐cyclotriphosphazene derivative and its application as flame retardant on cotton gauze

The halogen‐free flame retardance of natural fiber is an everlasting challenge due to the well‐known poor solubility of phosphazene in water. In this case, a new cyclotriphosphazene derivative (MCP) was synthesized. It was etherized hexamethylolmelamine (HMMM) and hexachloro‐cyclotriphosphazene (HCCP) by one pot reaction. It was characterized by ¹H NMR, ¹³C NMR, ³¹P NMR, FT‐IR, TGA, SEM, limited oxygen index (LOI) and vertical flame testing. The MCP has good solubility in water and thermosetting MCP has compact structure which can expand several times after burning. Cotton gauze was soaked in six different concentration of aqueous solutions of MCP (0 wt %, 5 wt %, 10 wt %, 15 wt %, 20 wt % and 25 wt %, respectively) to obtain the flame retardant cloth. The cloth was soaked in 20 wt % MCP solution had higher char yield and LOI. They had no any afterflame and afterglow, and gauze 2‐ gauze 5 cannot be burned out in 12s ignition time. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43555.     

Intrinsic flame-retardant epoxy resin composites with benzoxazine: Effect of a catalyst and a low curing temperature

Three kinds of inherent flame-retardant epoxy resin (EP) composites with 20 wt % benzoxazine (BOZ) were prepared with different curing processes with 2-methyl-1H-imidazole (MI) as a catalyst or/and changes in the curing temperature. The effects of the curing process on the flame retardancy, thermal stability, mechanical properties, and curing behaviors were investigated. The composite with added MI cured at low temperature (EBM–LT) had the best properties. It possessed a 35.3% limiting oxygen index and achieved a UL 94 V-0 rating. Thermogravimetric analysis indicated that EBM–LT had the best thermal stability among the three kinds of EP composites with BOZ. The EP composites with BOZ mainly displayed a condensed-phase flame-retardant mechanism. The mechanical properties improvement was attributed to the formation of a heterogeneous network. Differential scanning calorimetry indicated that MI reacted with EP and catalyzed the homopolymerization of BOZ, and EP reacted with BOZ. Fourier transform infrared spectroscopy analysis indicated that curing at lower temperature caused the formation of more homopolymers of BOZ. The relationship of the curing process, network structure, and properties of EP composites with BOZ was established; this could help with the design of high-performance EP composites with BOZ. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47847.