本质阻燃高分子研究进展

对全芳杂环、改性的磷酸酯类、含硅、含硼、含金属的无卤本质阻燃高分子的最新研究进展进行了较全面的概括,较详细地讨论了这四类无卤本质阻燃高分子的燃烧性能和热稳定性,将常规的本质阻燃高分子的概念扩展到了主链或侧链经化学改造后获得阻燃性提高的高分子。将具有本质阻燃特性的元素如B、Si、P、N或Sb、V、Ti、Cu引入高分子或反应性单体中,可以合成具有本质阻燃的高分子材料,增加材料的相容性和阻燃性,提高氧指数和材料的成炭率。含硅、硼的本质阻燃高分子在通用塑料和工程塑料阻燃上将是未来发展的重点方向。     

The flame‐retardant effect of calcium hypophosphite in various thermoplastic polymers

The flame‐retardant behavior of calcium hypophosphite (CaHP) was investigated in different thermoplastic polymers including polyamide 6 (PA), poly (lactic acid) (PLA), thermoplastic polyurethane (TPU), and poly methyl metacrylate (PMMA). CaHP was used at three different amounts of 10, 20, and 30 wt%. The characterization of the composites was performed using limiting oxygen index (LOI), vertical burning test (UL 94), thermogravimetric analysis (TGA), and mass loss calorimeter test. According to the test results, CaHP enhances the fire‐retardant properties in different levels depending on the polymer type. The CaHP exhibits its flame‐retardant effect via the formation of foamed char structure in the condensed phase and via the dilution and radical scavenging effect in the gas phase.     

Influence of ultrafine zinc borate on the thermal degradation behavior of a(low‐density polyethylene)/(intumescent flame retardant) system

The thermal degradation behavior of low‐density polyethylene (LDPE), LDPE treated with an intumescent flame retardant (LDPE/IFR), and LDPE treated with an intumescent flame retardant and ultrafine zinc borate (LDPE/IFR/UZB) was studied by (thermal gravimetric)‐(differential thermal) analysis (TG‐DTA) and cone calorimetry. The results of TG‐DTA showed that the initial degradation temperature increased, thermal degradation rate decreased, and the residual char amount increased substantially during the Pyrolysis process when ultrafine zinc borate was introduced into the LDPE/IFR system. The mass‐loss rate (MLR) curves and mass curves obtained by cone calorimetry showed that UZB could decrease the MLR and significantly enhance the residual char amount of LDPE/IFR during the combustion process. The results of Fourier transform infrared spectroscopy implied that a graphite‐like char and aromatic structures containing P‐O‐P, P‐O‐C, and B‐O‐B bonds were formed when LDPE/IFR/UZB was heated at high temperature. Scanning electronic micrographs of residual chars showed that ultrafine zinc borate improved char quality. X‐ray diffraction Studies implied that boron orthophosphate (BPO₄) formed in the residual char may play an important role in improving the structural properties of the char and is responsible for its good quality. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers     

Ecological issue of polymer flame retardancy

The use of polymer flame retardants has an important role in saving lives. The main flame retardant systems for polymers currently in use are based on halogenated, phosphorous, nitrogen, and inorganic compounds. All of these flame retardant systems basically inhibit or even suppress the combustion process by chemical or physical action in the gas or condensed phase. Conventional flame retardants, such as halogenated, phosphorous, or metallic additives, have a number of negative attributes. An ecological issue of the application of conventional flame retardants demands the search of new polymer flame retardant systems. Among the new trends of flame retardancy are intumescent systems, polymer nanocomposites, preceramic additives, low‐melting glasses, different types of char formers, and polymer morphology modification processing. The brief explanations on the three major types of flame retardant systems (intumescent systems, polymer nanocomposites, and polymer organic char formers) are the subject of this overview. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2449–2462, 2002     

Synthesis and characterization of new flame‐retardant poly(amide‐imide)s containing phosphine oxide and hydantoin moieties in the main chain

Six new flame‐retardant poly(amide‐imide)s (PAIs) 9a–f with high inherent viscosities containing phosphine oxide and hydantoin moieties in main chain were synthesized from the polycondensation reaction of N,N′‐(3,3′‐diphenylphenylphosphine oxide) bistrimellitimide diacid chloride 7 with six hydantoin derivatives 8a–f by two different methods such as solution and microwave assisted polycondensation. Results showed that the microwave assisted polycondensation, by using a domestic microwave oven, proceeded rapidly, compared with solution polycondensation, and was completed in about 7–9 min. All of the obtained polymers were fully characterized by means of elemental analysis, viscosity measurements, solubility test, and FTIR spectroscopy. Thermal properties and flame retardant behavior of the PAIs 9a–f were investigated using thermal gravimetric analysis (TGA and DTG) and limited Oxygen index (LOI). Data obtained by thermal analysis (TGA and DTG) revealed that these polymers showed good thermal stability. Furthermore, high char yields in TGA and good LOI values indicated that these polymers are capable of exhibiting good flame retardant properties. These polymers can be potentially utilized in flame retardant thermoplastic materials. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5062–5071, 2006     

Synergistic effect of phosphorus,nitrogen, and silicon on flame‐retardant properties and char yield in polypropylene

In this study, several flame retardants (FRs), containing phosphorus, nitrogen, and silicon, were synthesized. These synthesized FRs were blended with polypropylene (PP) to obtain mixture samples. The flame‐retardant properties of these mixture samples were estimated by the limiting oxygen index (LOI) value and thermal stabilities were characterized by thermogravimetric analysis. The LOI values of these samples were improved from 17.0 to 26.0 and the char yield increased from 0 to 27 wt %. A comparison of these samples, with respect to their LOI values and carbon yield, showed that the FRs, which simultaneously contained phosphorus, nitrogen, and silicon elements, can provide materials with the best flame‐retardant properties, suggesting that there is a synergistic effect among the three elements on the flame‐retardant properties and char yield when they are used in PP. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 854–860, 2005     

Structure and thermal property of intumescent char produced by flame‐retardant high‐impact polystyrene/expandable graphite/microencapsulated red phosphorus composite

This paper is aimed to illustrate the structure and thermal property of intumescent char produced by flame‐retardant polymers containing expandable graphite (EG). For this purpose, high‐impact polystyrene (HIPS) flame retarded by EG individually or in combination with microencapsulated red phosphorus (MRP) was prepared. The results indicate that the intumescent char from HIPS/EG/MRP composite, which contains a small amount of phosphorus element and more oxygen element, is much more compact and continuous than that from HIPS/EG composite with identical loading of flame retardant due to binding effect of phosphoric acid and its derivatives. The intumescent char produced by HIPS/EG/MRP composite exhibits much enhanced thermal and thermo‐oxidative stability as well as thermal‐insulating effect, which can withstand destruction of heat and oxygen effectively and thus provide a good fire‐proof barrier. The temperature beneath this intumescent char is decreased significantly in case of action by flame. By comparison, the porous and loose intumescent char generated by HIPS/EG composite has poor thermo‐oxidative endurance, and most of it can be consumed in air at high temperature without effective protection for the polymer. This has resulted in remarkable increase in flame retardancy of the HIPS/EG/MRP composite.     

Phosphate‐containing flame‐retardant polymers with good compatibility to polypropylene. I. The effect of phosphate structure on its thermal behavior

Phosphate‐containing flame‐retardant polymers were synthesized via a partial‐substitution reaction of poly(vinyl acetate) with stearylphosphonic chloride (SPPC) and diethylchlorophosphate in various substitution ratios. SPPC had been previously synthesized from phosphonic dichloride and stearyl alcohol. The synthesized SPPC and the flame‐retardant polymer products were characterized by Fourier transform infrared (FTIR) spectra analysis. The quantitative analysis of phosphorus in the polymer products was carried out by EDS (Energy Dispersion Spectrummeter) analysis. The real substitution ratios of the polymer products were estimated by the atomic number ratio of carbon and phosphate in products from EDS data. Variations in the glass‐transition temperature and thermal‐decomposition temperature of the products were investigated. The char of polymer products produced after thermogravimetric analysis (TGA) was also analyzed by FTIR, and the results show that different phosphate substitution leads to different char developments during the heating of TGA. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1125–1135, 2001     

聚合物成炭阻燃新进展

根据协效阻燃、硅氧烷阻燃、聚合物纳米阻燃和本质阻燃的方法和机理综述了聚合物阻燃在成炭方面的研究新进展。提高与聚合物基体的相容性、降低聚合物材料的性能损失、提高聚合物的成炭阻燃效率、兼顾对环境友好已成为聚合物阻燃的研究重点。综合使用多种阻燃方法正成为聚合物阻燃的研究方向。     

The mechanical properties and thermal performances of polypropylene with a novel intumescent flame retardant

A novel intumescent flame retardant: tetra‐spirophosphoryl‐benzoguanamine (TSPB) containing three constituents was used as a new flame retardant for polypropylene to prepare flame‐retardant materials, whose flammability and thermal behavior were studied by the limited oxygen index (LOI), thermogravimetric analysis (TGA), in addition whose mechanical properties were investigated in this work. It was found that when the addition of TSPB was 25 wt %, the LOI value of the PP could achieve to 29.5 and pass the UL‐94 V‐0 rating test. The TGA data showed that TSPB could enhance the thermal stability of PP and effectively increase the char residue formation. The mechanical performance test showed that the addition of TSPB improve the mechanical performances of PP to some extent. Thus, the trinity intumescent flame retardant TSPB is good to modify PP. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis of (1,4‐Methylenephenylphosphinic acid) Piperazine and Its Application as a Flame Retardant in Epoxy Thermosets

An efficient flame retardant (1,4‐methylenephenylphosphinic acid) piperazine (MPPAP) is successfully synthesized. The application of MPPAP in epoxy (EP) thermosets increases limited oxygen index values of composites to 30.2% and 6 wt% or more loading makes the materials get through UL94 V‐0 rating. The investigation of the combustion process indicates that MPPAP clearly changes the combustion behavior of EP composites, forms a char layer on the surface of the composites, and presents an effective flame inhibition effect, consequently resulting in clear reduction of the flammability and smoke production. The thermal degradation process of MPPAP/EP indicates that MPPAP promotes the matrix to decompose earlier and increases the char‐forming ability of composites. The morphology and structure of the final char shows MPPAP can promote the formation of cross‐linking structures and increase the graphitization degree of char residues acting as an excellent barrier. Furthermore, the flame‐retardant mechanism illuminates that MPPAP can reduce the generation of volatile fuels, and the pyrolysis products of MPPAP contain PO and PO₂, which exert free radical quenching effect in the gas phase. Therefore, MPPAP is a terrific flame retardant for epoxy thermosets which manifests a flame retarding action in the gas phase and condensed phase.     

金属有机骨架材料多功能阻燃聚合物应用研究进展

简要介绍了具有高孔隙率、催化吸附等特性的金属有机骨架（MOFs）材料的分类及合成方法,分别从改性以及未改性MOFs材料在聚合物中的阻燃应用及阻燃机理来阐述了近年来MOFs材料在聚合物材料阻燃方面的研究现状。最后,对其MOFs材料的应用前景进行了总结与展望。     

水性含磷聚合物在涂料中的应用研究进展

水性含磷聚合物具有良好的热稳定性、耐腐蚀性等优点,是一种重要的环境友好型材料。本文主要介绍了水性含磷丙烯酸类和聚氨酯类等重要的水性含磷聚合物,并对这两种聚合物的合成及其在水性防火涂料和防腐涂料中的应用进行了讨论。分析结果表明：以水性含磷聚合物为基料的防火涂料热稳定性较好,成炭率明显增加,阻燃性能大大提高;以水性含磷聚合物为基料的防腐涂料,漆膜附着力增强,防腐性能提高。提出今后的研究方向是：①将磷与卤素、氮、硅等元素同时引入水性聚合物中,以协同阻燃;②将含磷基团引入聚合物分子内,作为基料来提高阻燃性能。     

Study of a novel halogen‐free flame retardant system through TGA and structure analysis of polymers

Butadiene‐rubber toughened styrene polymers, such as acrylonitrile‐butadiene‐styrene (ABS) copolymer and high impact polystyrene (HIPS), are noncharring polymers. They are generally blended with polycarbonate (PC) or polyphenyleneether (PPE), which are char forming polymers, to improve char forming ability for styrenic blends containing conventional phosphate flame retardants. To achieve cost effective flame retardant system, PET was selected as a potential char‐source for ABS blends through the thermogravimetric analysis (TGA) and chemical structure analysis of various polymers. PET may contribute to the enhancement of flame retardancy of ABS/PET blends, especially in the presence of small amounts of phenol novolac (PN). The effective flame retardancy of this system is believed to be accomplished through the enhancement of interchain reactions by PN. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

涂料用本体阻燃树脂单体研究进展

本体阻燃树脂是让阻燃单体参与聚合反应,使之成为合成树脂的结构单元而赋予其较好的阻燃性能。该方法具有阻燃剂使用量少,所得树脂阻燃性能持久,基本不影响材料其他性能等优点。文章综述了近年来国内外研究人员对4类含有不同元素的涂料用本体阻燃树脂单体的研究进展,重点介绍了各类阻燃单体的合成方法,在不同合成树脂中的应用,以及所得树脂的成炭率、极限氧指数、UL-94测试等燃烧性能。最后,对涂料用本体阻燃树脂单体的发展前景作了展望。     

Phosphazene–triazine cyclomatrix network polymers: some aspects of synthesis,thermal‐ and flame‐retardant characteristics

Hydroxy phenyl‐substituted cyclotriphosphazenes were synthesized by reacting hexachlorocyclotriphosphazene with sodium phenolate and monosodium bisphenolate. The derivatives, consisting of a mixture of multi‐substituted and partly chain‐extended cyclophosphazenes, with overall functionality close to the targeted values, were transformed into the cyanatophenyl derivative. Thermal curing of the latter gave phosphazene–triazine cyclomatrix network polymers with varying ratios of phosphazene and triazine rings in the matrix. Although they manifested diminished T_g, the cured polymers were more thermally stable and provided higher char residue in comparison to the polycyanurate derived from bisphenol‐A dicyanate. The activation energies for thermal decomposition of the cyclomatrix networks increased with both phosphazene content and crosslink density, and showed a direct relationship with their thermal stability. The presence of phosphazene was conducive for enhancing the flame retardancy of the network. The flame retardancy improved with increase in crosslink density and char‐yielding property of the polymer, which implied that the flame‐retardant action was operative in the condensed phase. © 2000 Society of Chemical Industry     

Development of halogen‐free flame‐retardant thermoplastic elastomer polymer blend

Ethylene‐propylene diene rubber (EPDM) and isotactic polypropylene (iPP) blends have widest industrial applications that require a degree of flame retardancy. Halogen‐free intumescent technology based on phosphorous salt is a significantly advanced approach to make the polymer flame‐retardant. Both ammonium polyphosphate and ethylenediamine phosphate are important intumescent compounds. Their combination with carbonific and spumific agents were studied in binary blends of EPDM/PP. The polymer system was vulcanized online during melt mixing. Intumescent flame‐retardant polymer systems exhibit good flame‐retardancy with optimum comparable physiomechanical, electrical, and fluid resistance properties, including lower smoke emission, which is essential to protect people because the visibility remains unaffected in the event of fire. Pronounced charring and intumescent effect appear to enhance the flame‐retardancy of the polymers. Possible expected intumescent mechanism is proposed based on the nonpyrolysis mechanism for the flame‐retarded polymer and the intumescent components. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 407–415, 2004     

The effectiveness of magnesium carbonate‐based flame retardants for poly(ethylene‐co‐vinyl acetate) and poly(ethylene‐co‐ethyl acrylate)

In this report we outline recent work on the evaluation of magnesium carbonate‐based flame retardants for polymers commonly used in halogen‐free flame retardant wire and cable applications: poly(ethylene‐co‐vinyl acetate) (EVA) and poly(ethylene‐co‐ethyl acrylate) (EEA). Natural magnesium carbonate (magnesite), synthetic magnesium carbonate (hydromagnesite), and hydromagnesite/huntite blends were combined with EVA or EEA and tested for flame retardancy effectiveness with the cone calorimeter. The flammability results showed that the effectiveness of these carbonates was polymer dependent, suggesting that polymer degradation chemistry played a role in the flammability reduction mechanism. Hydromagnesites were, in general, more effective in reducing flammability, being comparable in performance to magnesium hydroxide. Finally, we report some polymer–clay (organically treated montmorillonite and magadiite) + magnesium carbonate flame retardant results which showed that the nanocomposite yielded mixed results. Specifically, the polymer–clay nanocomposite samples did not always yield the greatest reductions in peak heat release rate. Copyright © 2007 John Wiley & Sons, Ltd.