PVC阻燃抑烟的研究进展

介绍了聚氯乙烯(PVC)的热降解机理及燃烧特性。综述了PVC阻燃抑烟剂(如阻燃增塑剂、金属化合物、含硼阻燃剂、微胶囊红磷和无机填料等)的研究,特别提及了一些过渡金属(如Mo、Cu与Fe的化合物)在PVC抑烟中的明显作用。比较了各种阻燃抑烟方法的优缺点。采用阻燃剂和抑烟剂复合对PVC协同阻燃抑烟是未来的研究方向。     

Recent studies on the use of zinc borate as a flame retardant and smoke suppressant in PVC

By the Oxygen Index test, zinc borate alone is an effective flame retardant in rigid PVC. In flexible PVC formulations containing 50 phr of dioctyl phthalate as the plasticizer, zinc borate in combination with antimony oxide displays a synergistic effect at a total loading of more than 10 phr (1-to-1 ratio). In the presence of 30 phr of alumina trihydrate, this synergism increases significantly at a total loading as low as 5 phr. Zinc borate also shows strong synergism with alumina trihydrate. Zinc borate acts as a smoke suppressant in plasticized PVC. With alumina trihydrate, a strong smoke-reducing synergism is created. Zinc borate in a flexible PVC formulation markedly increases the amount of char formed, whereas the addition of antimony oxide, a vapor phase flame retardant, has little effect on char formation. Zinc borate is a good afterglow suppressant. Volatilized zinc derived from the zinc borate probably contributes to flame retardancy but not to smoke suppression. Zinc compounds can alter the pyrolysis chemistry by catalyzing dehydrohalogenation and promoting crosslinking, resulting in increased char formation and a decrease in both smoke production and flaming combustion.     

Flame‐retardant and smoke‐suppressant properties of zinc borate and aluminum trihydrate‐filled rigid PVC

The effects of zinc borate (ZB), aluminum trihydrate (ATH), and their mixture on the flame‐retardant and smoke‐suppressant properties of poly(vinyl chloride) (PVC) as well as their mechanism for flame retardancy and smoke suppression were studied through the limiting oxygen index (LOI) test, smoke density test, TGA, GC–MS, and SEM. The results show that incorporation of a small amount of ZB, ATH, and their mixture can greatly increase the LOI of PVC and reduce the smoke density of PVC during combustion. The mixture of ZB with ATH has a good synergistic effect on the flame retardance and smoke suppression of PVC. TGA and GC–MS analyses results show that incorporation of a small amount of ZB, ATH, and their mixture greatly promotes the char formation of PVC and decreases the amount of hazardous gases such as benzene and toluene released in PVC during combustion. Their mechanism is also proposed. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 3119–3127, 2000     

无机复合阻燃消烟剂在PVC材料中的应用

分析了高分子材料阻燃消烟的必要性，报道了研制的SY928系列无机复合阻燃消烟剂在PVC电工套管和电缆料中的应用效果。     

系列羟基锡酸盐对半硬质PVC的阻燃消烟作用

研究了系列羟基锡酸盐阻燃剂对半硬质PVC的阻燃消烟作用。通过对样品燃烧后剩炭含量及扫描电镜(SEM)分析,探讨了锡酸盐体系阻燃抑烟的机理。结果表明:经阻燃处理的样品具有较高的极限氧指数(LOI)和剩炭率,较低的烟密度等级(SDR)和最大烟密度(MSD),与未处理的样品相比具有较好的阻燃和消烟性能。由于阻燃剂的添加量较少,对材料力学性能影响不大。     

High‐molecular‐weight flexibilizers in low‐smoke flame‐retardant PVC compounds

Ethylene copolymer resin (ECR) modifiers play an important role in low‐smoke PVC. As high‐molecular‐weight flexibilizers, these resins reduce smoke and add strength and low temperature flexibility. This combination allows compounders to increase the amounts of flame‐retardant additives without compromising strength or flexibility or by adding liquids which increase smoke. This paper demonstrates these attributes versus liquid plasticizers used in PVC compounds.     

竹粉用量对PVC/竹粉复合材料阻燃抑烟性能的影响

采用自制的聚乙烯蜡接枝马来酸酐对竹粉进行改性,并制备了PVC/竹粉复合材料;研究了改性竹粉用量对PVC/竹粉复合材料阻燃抑烟性能的影响.结果表明:①PVC/竹粉复合材料的氧指数随着改性竹粉用量的增加而下降;②当改性竹粉的用量为10~50份时,PVC/竹粉复合材料的垂直燃烧性能达到FV-0级,水平燃烧性能达到FH-1级;...     

Zinc hydroxystannate‐coated metal hydroxides as flame retardant and smoke suppression for flexible poly vinyl chloride

Zinc hydroxystannate (ZHS)‐coated metal hydroxides were prepared. The effects of ZHS‐coated metal hydroxides on flame retardancy and smoke suppression of flexible poly vinyl chloride were studied by means of the limiting oxygen index, smoke density rating and the char yield test. The mechanism was investigated by thermogravimerty (TG), differential thermal analysis, and differential TG analysis and scanning electron microscopy. The results showed that ZHS‐coated metal hydroxides are more effective flame retardant and smoke suppressant than metal hydroxides, and it appears that tin compound may exert its action in both the condensed and vapor phases, but mainly in condensed phases as a Lewis acid. Copyright © 2009 John Wiley & Sons, Ltd.     

Pentaphenyl‐1,3,2‐dioxaphospholane as a reactive flame retardant

2,4,4,5,5‐Pentaphenyl‐1,3,2‐dioxaphospholane may be generated by treating benzpinacol with (dichloro)phenylphosphine. The phospholane contains a strained carbon–carbon bond which undergoes thermally‐induced homolysis at 70°C to generate a diradical capable of initiating styrene polymerization. The polymer generated from decomposition of the phospholane in the presence of styrene monomer contains phosphorus in the mainchain. This polymer exhibits thermal stability comparable to that of conventional polystyrene but decreased flammability. J. VINYL ADDIT. TECHNOL., 12:192–197, 2006. © 2006 Society of Plastics Engineers     

Low‐temperature synthesis of Mg(OH)2 nanoparticles from MgO as halogen‐free flame retardant for polypropylene

Mg(OH)₂ (MH) nanoparticles were synthesized by hydration of the light‐burned MgO at low temperature (70°C). Effects of additives, such as magnesium nitrate and magnesium acetate, on the size, morphology and agglomeration of MH particles were investigated. MH nanoparticles have platelet‐like structure and approximately 20–40 nm in thicknesses. The supersaturation degree plays an important role in magnesia hydration and is defined. When magnesium acetate was used as the additive, the hydroxyl ion can be homogeneously introduced into the solution. The size and morphology of MH nanoparticles are more homogeneous. Modified by titanate coupling agent, MH nanoparticles were used as the flame retardant for polypropylene (PP). The combustibility, mechanical properties and thermal behaviors of the PP/MH composites were characterized. The mechanical properties of PP/MH composites are not seriously deteriorated with increasing MH content. When the amount of MH fraction reached 65, the limiting oxygen index (LOI) value and UL 94 testing result of MH65 are 33.8 and V‐0 grading, respectively. The onset temperature (T_10%) and the maximum thermal decomposition temperature (T_max) of MH65 separately increased by approximately 100°C and 77°C than those of neat PP. Copyright © 2012 John Wiley & Sons, Ltd.     

Zinc compounds as flame retardants and smoke suppressants for rigid PVC

Abstract

The effect of the concentration of zinc hydroxy-stannate and zinc borate on the fire performance of rigid PVC formulations has been investigated. Fire testing was carried out using cone calorimetry as well as the limiting oxygen index (LOI) test. In addition, further testing was done to check that incorporation of the fire retardant additives did not have any detrimental effects on other properties of the formulated PVC, such as heat stability, colour or impact strength. The results demonstrated that zinc hydroxy-stannate is an excellent fire retardant and smoke suppressant at additions levels of 3 parts per hundred parts of PVC. Zinc borate did not have the excellent fire retardant properties of zinc hydroxy-stannate, but was found to be an efficient and cost-effective smoke suppressant, although the presence of free zinc oxide in the sample affected the thermal stability of the formulation.     

Metal hydroxystannates as flame retardants and smoke suppressants for semirigid poly(vinyl chloride)

Metal hydroxystannates were studied as flame retardants and smoke suppressants for semirigid poly(vinyl chloride) (PVC). The flame‐retardant and smoke‐suppression mechanisms were investigated by using limiting oxygen index (LOI), smoke density rating (SDR), the solid yield test (SY), scanning electron microscopy (SEM), thermogravimetry, differential thermogravimetry, and differential thermal analysis. Results showed that semirigid PVC treated with the flame retardants had a higher LOI, and solid yield, but a lower SDR and maximum smoke density, thereby indicating that the flame‐retardance and smoke‐suppression properties of the treated PVC were improved and that the hydroxystannate compounds could be used as highly effective flame retardants. The tin compounds may exert their action in both the condensed and vapor phases, but mainly in the condensed phase as Lewis acids. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers.     

无机阻燃剂对PVC/木粉复合材料性能的影响

分别采用A1(OH)3、ZB以及Sb2O3等无机阻燃剂对PVC/木粉复合材料改性,研究不同的阻燃剂配方及阻燃剂含量对PVC/木粉复合材料阻燃性能和力学性能的影响。结果表明:随着A1(OH)3,ZB以及Sb2O3添加量的增加,PVC/木粉复合材料的氧指数(LOI)呈逐渐增大的趋势。Sb2O3阻燃效率最高,当添加量为9份时,氧指数达到35.2%;无机阻燃剂的加入普遍降低了PVC/木粉复合材料的冲击韧性,但对拉伸强度起到了一定的增强作用。     

Zinc‐based compounds as smoke suppressant agents for an aerospace epoxy matrix

Smoke is considered to be the main hazard of fires involving epoxy resins but its production depends on many variables, principally the chemical character and the burning rate of the polymer plus the availability of oxygen. The work reported aimed to study the smoke suppressant effect and flammability performance of zinc‐based compounds (FR system) in epoxy matrix composites used in the aerospace and aeronautical industry. The flammability performance of neat and FR‐loaded systems was screened using microcombustion calorimetry, while smoke generation, in terms of carbon monoxide (CO) and carbon dioxide (CO₂) production, was analysed under dynamic conditions using cone calorimetry. Final results indicate that the dispersion of zinc borate and zinc hydroxystannate (ZHS) into epoxy matrices leads to a significant variation in flame retardant properties reducing both total heat release by about 25 and 30%, respectively, and heat release capacity by about 30 and 50%, respectively. The system containing ZHS shows an enhancement in all smoke suppressant properties; both tin compounds (zinc stannate (ZS) and ZHS) give a reduction of CO₂/CO ratio from 41 to 25 for ZS and from 41 to 36 for ZHS compared to neat matrix. Copyright © 2010 Society of Chemical Industry     

Thermal properties of polyethylene flame retarded with expandable graphite and intumescent fire retardant additives

Low‐density polyethylene was flame retarded by combinations of expandable graphite with either ethylenediamine phosphate or 3,5‐diaminobenzoic acid phosphate. Cone calorimeter, laser pyrolysis, and open flame exposure tests (supported by video and infrared camera data capture and analysis) were conducted to assess ignition and burn behavior. Cone calorimeter results indicated substantial reductions in the peak heat release rates for all flame‐retarded samples but with reduced ignition times and increased flame out times. Smoke generation was suppressed in the presence of expandable graphite. Infrared and video data from open flame fire tests indicated cohesive bonding of expanded strings and thermal shielding properties in all binary systems. All binary systems delivered fire retardation exceeding any of the single fire retardant compounds. They were also able to withstand higher temperatures before ignition, burn through, or sag occurred. All ethylenediamine phosphate‐containing binary systems prevented sample burn through, maintaining structural integrity of samples until eventual melting of the polymer media occurred. Thermogravimetric analysis laser pyrolysis results confirmed the good thermal shielding imparted by the intumescent additives. Copyright © 2016 John Wiley & Sons, Ltd.     

Fire and thermal properties of PA 66 resin treated with poly‐N‐aniline‐phenyl phosphamide as a flame retardant

In this study, a halogen‐free phosphorous‐nitrogen synergistic flame retardant, poly‐N‐aniline‐phenyl phosphamide (PDPPD), was synthesized. Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and elemental analysis data confirmed the structure of PDPPD. The essential FR PA66 was polymerized with PA66 pre‐polymer and PDPPD pre‐polymer, prepared from PDPPD and adipic acid. The limit oxygen index and UL‐94 test results of FR PA66 reached 28% and V‐0, respectively, when the contents of PDPPD pre‐polymer were 4.5 wt%. The thermo‐gravimetric and differential scanning calorimetry results demonstrated that the initial decomposition temperature of FR PA66 was 43 °C lower than that of pristine PA66 from 385 to 342 °C; however, the peak decomposition temperature was 36 °C higher than that of pure PA66 from 437 to 473 °C, when the contents of PDPPD pre‐polymer reached 4.5 wt%. Flame retardant mechanism was studied by cone calorimeter testing and SEM‐EDX, confirming that the heat release rate (HRR), total heat release (THR), and total smoke product (TSP) decreased slightly, and PDPPD followed the gas phase flame retardant mechanism. Copyright © 2016 John Wiley & Sons, Ltd.     

Intercalated kaolinite with ammonium dihydrogen phosphate as an effective flame retardant to enhance the flame retardance and smoke suppression of epoxy resins

To improve the compatibility and flame retardance of kaolinite (Kaol) in polymeric materials, ammonium dihydrogen phosphate (ADP) was intercalated into kaolinite to obtain a novel intercalated kaolinite (K-ADP) for enhancing thermal stability, flame retardance, smoke suppression, and mechanical performance of epoxy resins (EPs). The results show that the presence of K-ADP exerts a more positive effect on reducing the heat release and smoke generation of EPs than the same addition of Kaol. Condensed phase analysis shows that EP/K-ADP composite generates more aromatic cross-links in the condensed phase to reinforce the compactness and intumescence of char compared to EP/Kaol composite. Especially, 5 wt% K-ADP confers a 43.7% reduction in peak heat release rate value and a 36.3% reduction in peak smoke production rate value to EP. Toxic gases analysis shows that K-ADP conduces to inhibiting the release of combustible gases including isocyanates and aromatic volatiles, and generating incombustible gases including ammonia and carbon dioxide to reduce the intensity of EP combustion. The mechanical test shows that K-ADP imparts less adverse impact on mechanical behavior to EP composites than Kaol due to the good dispersion and compatibility between K-ADP with EP matrix.     

Effect of triphenyl phosphate flame retardant on properties of arylamine‐based polybenzoxazines

Three types of arylamine‐based benzoxazine resins modified with both condensed‐phase and gas‐phase action flame retardant, i.e. triphenyl phosphate (TPP) at various weight ratios were investigated. From rheological study, it was found that the viscosity of benzoxazines/TPP mixtures were significantly lower than that of the neat benzoxazine monomers suggesting flow property enhancement. Furthermore, differential scanning calorimetry results revealed that the onset and the maximum temperatures of the exothermic peak, due to the ring opening polymerization of benzoxazine resins, shifted to lower temperatures with increasing TPP. In addition, all polybenzoxazines possessed relatively high char yield, which increased as the TPP content increased thus enhancing their flame retardancy. The limiting oxygen index values of the flame retarded polybenzoxazines also increased with TPP addition. The maximum flame retardancy of UL94 V‐0 class was obtained with an addition of only few percents of TPP in the polybenzoxazines. Flexural strength, flexural modulus, and glass transition temperature of those polybenzoxazines tended to decrease with an addition of TPP mainly due to its plasticizing effect. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1074‐1083, 2013     

Synthesis of flame retardant polyester‐urethanes and their applications in nanoclay composites and coatings

This paper describes the synthesis of phosphorus‐containing polyester‐urethanes and their applications in nanoclay composites and coatings. Polyester was prepared by the reaction of bis(bisphenol‐A) monophenyl phosphonate, maleic anhydride and phthalic anhydride. The polyester was reacted with various diols such as ethylene glycol, diethylene glycol and propylene glycol to obtain polyester polyols. Synthesized polyester polyols were characterized by chemical analysis and instrumental analysis and was used further to react with different isocyanates to develop polyester‐urethanes. The synthesized polyester‐urethanes were blended with organo‐modified montmorillonite nanoclay (1 wt%, 3 wt% and 5 wt%) and were cast in a mold and coated on mild steel panels. The thermal stability of neat polyester‐urethane and the nanoclay composites was determined by thermogravimetric analysis. The flame retardant properties of cast films and their composites were determined by the limiting oxygen index and UL‐94 test methods. The physical and mechanical properties of coatings such as pot life, drying properties, scratch hardness, pencil hardness, impact resistance, adhesion and flexibility were investigated. The chemical resistance properties of the coatings were also determined in different reagents. The data reveal that the polyester‐urethane nanoclay composites with 3 wt% clay hold promise for use in effective flame retardant coatings. © 2013 Society of Chemical Industry