四元复合体系在硬质聚氨酯泡沫材料中的逐级释放阻燃行为研究

以甲基膦酸二甲酯（DMMP）、10-（2,5-二羟基甲苯）-10-氢-9-氧杂-10-磷酰杂菲-10-氧化物（DOPO-HQ）、可膨胀石墨（EG）和氢氧化铝（ATH）构建了四元阻燃复合体系,并通过热失重分析仪（TG）、锥形量热仪、极限氧指数分析仪等研究了其在硬质聚氨酯泡沫（RPUF）中的阻燃行为。结果表明,四元阻燃体系能够在较宽温度区间内发挥逐级释放的协同阻燃效应;DOPO-HQ能够与EG/DMMP/ATH三元阻燃体系形成加合阻燃效应,使得RPUF复合材料的极限氧指数（LOI）提升至30.8%;与采用EG/DMMP/ATH三元阻燃体系的RPUF复合材料相比,采用加入DOPO-HQ的四元阻燃体系的RPUF复合材料的热释放速率峰值（PHRR）、总热释放量（THR）、总烟释放量（TSR）均有所下降,残炭率得到了进一步提升,说明DOPO-HQ与EG/DMMP/ATH所构建的四元阻燃体系在成炭性方面具有协同效应;此外,通过扫描电子显微镜（SEM）对残炭进行表征,验证了四元阻燃体系在凝聚相中能够发挥优异的成炭阻隔效应,并能够在燃烧的初期、中期和末期发挥逐级释放阻燃效应。     

碱式碳酸镁基复合阻燃剂的制备及其阻燃性能研究

采用硅烷表面处理的碱式碳酸镁纳米片和氢氧化镁以及氢氧化铝为复合阻燃剂,通过密炼模压法制备了一系列复配阻燃剂协效阻燃EVA的复合材料。利用拉伸性能测试仪、熔融指数仪、垂直燃烧测试仪和锥形量热仪分别测试了复合材料的力学性能、加工流动性能和阻燃性能,利用热重分析仪测试了复配阻燃剂的热分解行为。结果表明,复配阻燃剂以适当比例协效阻燃EVA在更宽的燃烧温度范围内发生分解,能够起到更好的阻燃效果。并且复配阻燃剂/EVA复合材料的热释放速率和烟释放率大幅度降低,分别为181.06 kW/m²和0.032 m²/s。另外,复配阻燃剂/EVA复合材料的拉伸强度达到9.73 MPa,断裂伸长率为155.07%,每10 min熔融指数为1.00 g,符合电线电缆行业标准。     

Enhanced flame retardancy,smoke suppression,and acid resistance of polypropylene/magnesium hydroxide composite by expandable graphite and microencapsulated red phosphorus

Low flame retardant efficiency and poor acid resistance of filled polymer composites are two main drawbacks of magnesium hydroxide (MH) as a flame retardant (FR). To solve these problems, expandable graphite (EG) and microencapsulated red phosphorus (MRP) were introduced into polypropylene/magnesium hydroxide (PP/MH) composite by melt compounding. The obtained PP/MH/EG/MRP quadruple composite was studied regarding its fire behavior as well as acid resistance. Obvious flame retardant synergism among MH, EG, and MRP is found in PP, which diminishes the loading of FR from 63.0 to 37.5 wt% to obtain V-0 rating in UL-94 test and low smoke release. Compact intumescent char with high thermo-oxidative stability was generated on composite surface, which plays a vital role in flame retardancy. The removal of MH by acid erosion on PP/MH/EG/MRP composite surface does not affect production of intumescent char and fire behavior of this composite. The composite displays good fire retardancy, smoke inhibition, and acid resistivity concurrently. This article renders an easy and cheap route to overcome the main faults of MH.     

The flame retardant behaviors and synergistic effect of expandable graphite and dimethyl methylphosphonate in rigid polyurethane foams

A series of flame‐retardant rigid polyurethane foams (RPUFs) containing dimethyl methylphosphonate (DMMP) and expandable graphite (EG) were prepared by box‐foaming. The RPUFs were characterized by thermogravimetric analysis (TGA), the limiting oxygen index (LOI), cone calorimeter, and scanning electron microscope (SEM). The decomposition process of DMMP was investigated by Pyrolysis‐Gas Chromatography/Mass Spectroscopy (Py‐GC/MS). Accordingly, their flame retardant behaviors and mechanism were also discussed. The results show that the DMMP/EG system can linearly enhance the LOI value from 19.2% of the pure RPUF to 33.0% of RPUFs containing 16 wt% flame retardant. In addition, the DMMP/EG system also remarkably increases yields of the residual char and drastically decreases the peak value of heat release rate (PHRR), heat release rate (HRR), total heat release (THR), total smoke release (TSR), and the yields of CO (COY). In the flame retardant RPUFs, when the matrix is ignited, the flame retardant DMMP should be decomposed to gaseous PO₂ fragments, which can inhibit free radical chain reaction of flammable alkyl free radical from the decomposed matrix; whereas the flame retardant EG can rapidly expand and form loose and worm‐like expanding graphite char layer accordingly, which can hinder the heat transmission to the inner matrix and reduce decomposing velocity of matrix. After the combination of the two flame retardant effects, the DMMP/EG flame retardant system provides the matrix with better flame retardant effects than one of them does. Namely, it shows excellent gas‐condensed bi‐phase synergistic effect. POLYM. COMPOS., 35:301–309, 2014. © 2013 Society of Plastics Engineers     

基于磷杂菲衍生物多组分无卤阻燃天然橡胶的制备及性能

将磷杂菲/三嗪双基协同阻燃剂（TGD）、甲基膦酸二甲酯（DMMP）、可膨胀石墨（EG）及氢氧化铝（ATH）复配添加到天然橡胶（NR）中制备阻燃NR硫化胶,考察了TGD/DMMP/EG/ATH复配阻燃剂对NR硫化胶的阻燃性能、热稳定性及物理机械性能的影响。结果表明,TGD/DMMP/EG/ATH复配阻燃剂可有效提升NR硫化胶的阻燃性能和热稳定性,并降低燃烧过程中的热释放速率。当TGD/DMMP/EG/ATH复配阻燃剂的用量为60份（质量）时,NR硫化胶的极限氧指数可达28.4%,残炭质量分数可达25.61%,热释放速率可降低95%,总热释放量可降低21%。TGD/DMMP/EG/ATH复配阻燃剂对NR硫化胶的物理机械性能影响不大。     

Addition flame‐retardant effect of nonreactive phosphonate and expandable graphite in rigid polyurethane foams

A series of flame‐retardant rigid polyurethane foams (RPUFs) containing nonreactive phosphonate (5‐ethyl‐2‐methyl‐1,3,2‐dioxaphosphorinan‐5‐yl) methyl dimethyl phosphonate P‐oxide (EMD) and expandable graphite (EG) were prepared by water blown. The flame‐retardant properties and mechanism of EMD/EG on RPUFs were systematically investigated. The EMD/EG system effectively increased the limiting oxygen index (LOI) value and decreased the values of total heat release (THR), av‐effective heat of combustion (EHC), pk‐heat release rate (HRR), total smoke release (TSR) of RPUFs. The impact values of LOI, THR, and av‐EHC resulted by EMD/EG system are nearly equal to the sum of the impact values by EMD and EG individually in RPUFs, which implies the addition flame‐retardant effect from EMD and EG. EMD alone exerted excellent gas‐phase flame‐retardant effect by releasing PO fragments with quenching effect. The firm residue produced by EMD combined well with the loose and worm‐like expanded graphite from EG further to form compact and expanded char layer, which brought excellent barrier effect and filtration effect to matrix. That's why pk‐HRR and TSR values of RPUF reduced. Depending on the simultaneous actions of EMD/EG system in gas phase and condensed phase during combustion, the flame‐retardant effects from nonreactive phosphonate and EG on RPUFs were added together. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45960.     

Synergistic effect of expandable graphite and aluminum hypophosphite on flame‐retardant properties of rigid polyurethane foam

A series of flame retarding rigid polyurethane foam (RPUF) composites based on expandable graphite (EG) and aluminum hypophosphite (AHP) were prepared by the one‐pot method. The properties were characterized by limiting oxygen index (LOI) test, cone calorimeter test, thermogravimetric analysis (TGA), real‐time Fourier transform‐infrared spectra (RT‐FT‐IR), X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), etc. The results indicate that both EG and AHP could enhance the flame retardency of RPUF composites. Besides, the flame retardant effect of EG was better than that of AHP. The results also show that partial substitution of EG with AHP could improve the flame retardency of RPUF, and EG and AHP presented an excellent synergistic effect on flame retardancy. What is more, compared with RPUF/20EG and RPUF/20AHP, the heat release rate (HRR) and total heat release (THR) of RPUF/15EG/5AHP were lower.TGA results indicate that partial substitution of EG with AHP could improve the char residue which provided better flame retardancy for RPUF composites. The thermal degradation process of RPUF composites and the chemical component of the char residue were investigated by RT‐FT‐IR and XPS. And the results prove that RPUF/15EG/5AHP had higher heat resistance in the later stage. Compared with the RPUF composites filled with EG, a better cell structure and mechanical properties were observed with the substitution of AHP for part of EG. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42842.     

Effects of poly(ethylene‐co‐propylene) elastomer on mechanical properties and combustion behaviour of flame retarded polyethylene/magnesium hydroxide composites

Magnesium hydroxide‐based halogen‐free flame retarded linear low density polyethylene composites containing poly(ethylene‐co‐propylene) elastomer were prepared in the melt process and subsequently vulcanized thermally. Influences of the elastomer on the mechanical properties, combustion characteristics and crystallization behaviour of polyethylene/magnesium hydroxide composites have been investigated. The results from the mechanical tests show that the incorporation of a suitable amount of elastomer into polyethylene/magnesium hydroxide composites after vulcanization can increase both the tensile strength and elongation greatly, compared with those of the composites without the elastomer. It has been found that the properties such as limiting oxygen index, UL‐94 rating, the time to ignition and the rate of heat release of polyethylene/magnesium hydroxide/elastomer composites are all improved in comparison with polyethylene/magnesium hydroxide composites at the same retardant level. Scanning electron microscopy studies show that the incorporation of the elastomer into polyethylene/magnesium hydroxide composites improves the compatibility between the filler and the polymer substrate. The degrees of crystallinity of polyethylene/magnesium hydroxide/elastomer composites decrease with increasing the elastomer content. © 2002 Society of Chemical Industry     

Flame retardant and thermal decomposition properties of flexible polyurethane foams filled with several halogen‐free flame retardants

Expandable graphite (EG), dimethyl methylphosphonate (DMMP), melamine (MEL), zinc borate (ZB), or magnesium hydroxide (MH) was separately added to polyurethane to form flame retardant flexible polyurethane foam (FPUF) in one‐step. The cell morphologies of the FPUF composites before and after burning were observed by scanning electron microscopy (SEM), their flammability was evaluated by limiting oxygen index (LOI) tests, and their thermal stability and evolved gaseous products were examined by thermogravimetric analysis‐Fourier transform infrared spectroscopy (TGA‐FTIR). The results indicated that all the five flame retardants could improve the flame retardant performance of FPUF on the basis of their own mechanism. DMMP possessed the highest flame retardant efficiency, and one of the important reasons was that it could promote the formation of char. EG could inhibit molten drop of FPUF during burning effectively. All the five flame retardants could decrease the maximum decomposition velocity mainly because of their heat absorption effect. ZB displayed an excellent inhibition ability for the release of the evolved gaseous products because of its adsorption effect. All the flame retardants except DMMP were capable to decrease the CO yield at the temperature (400°C) of maximum decomposition velocity for their respective mechanisms, but all of them were not able to inhibit CO generation at higher temperature (600°C). POLYM. ENG. SCI., 54:2497–2507, 2014. © 2013 Society of Plastics Engineers     

PVAc/OMMT纳米复合物的制备及其在阻燃PP中的应用

通过原位乳液插层法制备了有机蒙脱土(OMMT)含量较高的聚醋酸乙烯酯/有机蒙脱土(PVAc/OMMT)纳米复合物,并将其作为阻燃母料与氢氧化镁(MH)复配,与聚丙烯(PP)熔融共混制备了性能良好的无卤阻燃PP,用X射线衍射(XRD)、锥形量热分析(CONE)等对材料进行了表征。结果表明:当OMMT和MH的用量分别为3%和40%时,阻燃PP的热释放速率峰值(PHRR)相比于基体树脂从929.0kW/m2降低至193.7kW/m2,总释放热(THR)从165.2MJ/m2降低到73.6MJ/m2。     

“一锅法”合成双组分镁基阻燃剂及性能研究

基于轻烧氧化镁为原料,通过“一锅法”合成了一种具有氢氧化镁（MH）和碱式碳酸镁（MC）双组分多级结构的一体化高效无卤复合阻燃剂（MCMH）。将MCMH和MH分别与聚丙烯（PP）密炼共混,经模压成型制备了PP/MCMH和PP/MH复合材料,并对比研究了MCMH与MH应用于PP的阻燃性能。结果表明,合成的MCMH是氧化镁先水化转变为氢氧化镁,然后部分氢氧化镁与碳酸氢铵反应生成碱式碳酸镁,呈现花状多级结构。当阻燃剂质量分数占复合材料的50%时,PP/MCMH复合材料的热释放速率（HRR）峰值和烟雾产生率（SPR）峰值较PP/MH复合材料大幅降低,分别为299 kW/m²和0.038 m²/s。该方法原料来源广泛,工艺简单易行,具有规模化生产和应用的潜力。     

阻燃剂对热固性酚醛树脂阻燃性能影响的研究

通过氧指数、垂直燃烧等级及产烟率测定研究了氢氧化铝(ATH)、氢氧化镁(MH)、膨胀石墨(EG)、膨胀型阻燃剂(IFR)等以单一或协同复配的形式对酚醛树脂(PF)体系阻燃性能的影响,并采用差热分析(DTA)对体系的微观热行为进行了研究。结果表明,放热量最小的体系为ATH/MH/EG/PF,ATH/MH/EG/IFR/PF体系的氧指数最大,达到96。ATH/MH/PF体系的产烟率最低(72%)。添加阻燃剂后,体系的垂直燃烧等级可提高到UL94V-0级。     

Improved flame resistance properties of unsaturated polyester resin with TiO2-MXOY solid superacid

Five SO₄^2-/TiO₂-M_XO_Y solid super acids (SSA: Cu@Ti:SSA, Zr@Ti:SSA, Fe@Ti:SSA, Mn@Ti:SSA, Mo@Ti:SSA) were successfully prepared by sol-gel method, and its chemical structure and element content were characterized by X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR) and energy dispersive spectroscopy (EDS). Then, a compound flame retardant system containing SSA and ammonium polyphosphate/montmorillonite (AM) were was introduced into an unsaturated polyester resin (UPR) to enhance the flame retardance. The effect of SSA on the flammability and thermal stability of the UPR was evaluated by the limiting oxygen index (LOI), cone calorimeter test (CCT) and thermogravimetric analysis (TGA). The LOI results showed that the flame retardance of the UPR composites was significantly improved with the addition of SSA. Moreover, their heat release rate (HRR), total heat release (THR), the smoke production rate (SPR) and CO and CO₂ yield were much decreased. In addition, the initial decomposition temperature of UPR/AM/SSA was delayed, indicating that their thermal stability was increased, and the residual char of UPR/AM/SSA was also increased due to strong catalytic of SSA ability for esterification and dehydration. Furthermore, the microstructure of the residual char after combustion of the UPR composites was studied by the scanning electron microscopy (SEM), and it was found that the char layer structure was more continuous and dense after the addition of the SSA. In sum up, the synergistic effect between SSA and AM was the main factor for the great improvement of flame retardant of UPR composites.     

Combustion characteristics of halogen‐free flame‐retarded polyethylene containing magnesium hydroxide and some synergists

Halogen‐free flame‐retarded polyethylene materials have been prepared by using magnesium hydroxide (MH) as a flame retardant combined with red phosphorous (RP) and expandable graphite (EG) as synergists. The effects of these additives on the combustion behavior of the filled linear low density polyethylene (LLDPE), such as a limiting oxygen index (LOI), the rate of heat release (RHR), the specific extinction area (SEA), etc., have been studied by the LOI determination and the cone calorimeter test. The results show that RP and EG are good synergists for improving the flame retardancy of LLDPE/MH formulations. In addition, a suitable amount of ethylene and vinyl acetate copolymer (EVA) added in the formulations can increase the LOI values while promoting the char formation and showing almost no effect on the RHR and SEA values. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 206–214, 2001     

Layer-by-layer assembled bagasse to enhance the fire safety of epoxy resin: A renewable environmental friendly flame retardant

In an effort to make rational use of resources, wasted bagasse were collected, and then fabricated by layer-by-layer (LbL) assembly to prepare an environmentally benign flame retardant for epoxy resin (EP). Six chitosan/ammonum polyphosphate bilayers were successfully deposited on the surface of bagasse, which endows EP/6BL@BF composites with a limiting oxygen index value of 24.1% and V-1 rating in UL-94 test. Compared with untreated bagasse, cone calorimetry test reveals that the incorporation of 6BL@BF reduces the peak heat release rate and total heat release by 64.6% and 13.2%, respectively. Besides, expandable graphite (EG) was combined with 6BL@BF to further enhance the fire safety and thermal stability of EP composites. Furthermore, the gas and condensed phase analysis of EP/6BL@BF/EG-3 composite was investigated by TG-IR, scanning electronic microscopy, Laser Raman spectroscopy, and X-ray photoelectron spectroscopy, and the flame retardant mechanism of 6BL@BF/EG was proposed. Finally, the mechanical properties of EP composites were investigated systematically.     

膨胀石墨对乙烯基硅橡胶的阻燃作用研究

将可膨胀石墨(EG)添加到乙烯基硅橡胶中并采用过氧化物硫化制备了硅橡胶材料,对其阻燃性能和燃烧行为进行了研究.结果表明,当EG的添加量为5份时,材料在垂直燃烧测试中通过了UL 94 V-0级,且能离火自熄,极限氧指数达到了33.0％;与纯硅胶材料相比,EG的加入有效降低了材料的热释放和烟释放;材料与火焰接触区域,EG完...     

Expandable graphite encapsulated by magnesium hydroxide nanosheets as an intumescent flame retardant for rigid polyurethane foams

Encapsulation of expandable graphite (EG) particles by organic or inorganic shells has been proved to efficiently enhance the expandability of EG, and thus to improve the flame‐retardant efficiency of EG. In this study, magnesium hydroxide (MH) nanosheets were utilized to fabricate core–shell EG@MH flame‐retardant particles through a heterocoagulation method. It was observed that after the encapsulation by MH nanosheets, the edges of the char residue of the EG layer were sealed after combustion, which contributed to the enhancement of expandability. The expansion volume of EG@MH increased dramatically to 456 mL/g, in contrast to 338 mL/g for pure EG. By incorporating 11.5 wt % of flame‐retardant particles, polyurethane foam containing EG@MH (here PU‐EG@MH) displayed excellent flame retardancy. Compared with the physically mixed sample, PU‐EG+MH, the limiting oxygen index value for the PU‐EG@MH sample increased from 29.8% to 32.6%. Furthermore, the shell of MH nanosheets was beneficial for improving the interfacial adherence between EG and the rigid polyurethane foam (RPUF) matrix, due to the reaction between isocyanate functional groups and MH. The cell structure and storage modulus of PU‐EG@MH were improved. In other words, the shell of MH nanosheets successfully improved the flame‐retardant efficiency and enhanced the interface adhesion between EG and the matrix. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46749.     

MRP/MH/EG协同阻燃HDPE的性能研究

以微胶囊化红磷(MRP)、氢氧化镁(MH)及可膨胀石墨(EG)为阻燃剂,采用熔融挤出法制备了多组高密度聚乙烯(PE-HD)阻燃复合材料。采用氧指数测试、垂直燃烧测试、红外光谱分析、激光拉曼光谱分析、热重-差热分析、扫描电子显微镜分析及拉伸性能测试等方法对复合材料的阻燃性能、热稳定性、力学性能和断面的微观形貌进行了研究,并探讨了阻燃机理。结果表明,单独使用EG时阻燃效果差,但将EG与MRP、MH复配使用能有效改善材料的阻燃性能;当PE-HD/MH /MRP /EG = 100/35/15/5(质量份,下同)时,复合材料的氧指数为28.5 %,垂直燃烧达到UL 94 V-0级,而阻燃剂的加入对材料拉伸性能的影响并不是很大;SEM分析表明, EG与PE-HD基材有很好的相容性,而MRP或MH与PE-HD基材的相容性较差。     

Improved flame resistance properties of unsaturated polyester resin with TiO2-MXOY solid superacid

Five SO₄²⁻/TiO₂-M_XO_Y solid super acids (SSA: Cu@Ti:SSA, Zr@Ti:SSA, Fe@Ti:SSA, Mn@Ti:SSA, Mo@Ti:SSA) were successfully prepared by sol–gel method, and its chemical structure and element content were characterized by X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR) and energy dispersive spectroscopy (EDS). Then, a compound flame retardant system containing SSA and ammonium polyphosphate/montmorillonite (AM) were was introduced into an unsaturated polyester resin (UPR) to enhance the flame retardance. The effect of SSA on the flammability and thermal stability of the UPR was evaluated by the limiting oxygen index (LOI), cone calorimeter test (CCT) and thermogravimetric analysis (TGA). The LOI results showed that the flame retardance of the UPR composites was significantly improved with the addition of SSA. Moreover, their heat release rate (HRR), total heat release (THR), the smoke production rate (SPR) and CO and CO₂ yield were much decreased. In addition, the initial decomposition temperature of UPR/AM/SSA was delayed, indicating that their thermal stability was increased, and the residual char of UPR/AM/SSA was also increased due to strong catalytic of SSA ability for esterification and dehydration. Furthermore, the microstructure of the residual char after combustion of the UPR composites was studied by the scanning electron microscopy (SEM), and it was found that the char layer structure was more continuous and dense after the addition of the SSA. In sum up, the synergistic effect between SSA and AM was the main factor for the great improvement of flame retardant of UPR composites.     

Combustion characteristics and synergistic effects of red phosphorus masterbatch with expandable graphite in the flame retardant HDPE/EVA composites

In this work, the flammability behaviors and synergistic effects of red phosphorus masterbatch (RPM) with expandable graphite (EG) in flame‐retardant high‐density polyethylene/ethylene vinyl‐acetate copolymer (HDPE/EVA) composites have been investigated by limiting oxygen index (LOI), UL‐94 test, cone calorimeter test (CCT), thermogravimetric analysis (TGA), Fourier‐transform infrared (FTIR) and scanning electron microscopy (SEM). The data obtained from LOI, UL‐94 test and CCT showed that suitable amount of RPM had synergistic effects with EG in the HDPE/EVA/EG/RPM composites. The addition of RPM greatly increased the LOI values by 3.4%, obtained UL‐94 V‐0 rating, decreased the heat release rates and total heat release, and prolongated the ignition time when 6.7 phr RPM substituted for EG in the HDPE/EVA/EG/RPM composites. The data from TGA and FTIR spectra also indicated the synergistic effects of RPM with EG considerably enhanced the thermal degradation temperatures. The morphological observations after UL‐94, CCT, and SEM images presented positive evidences that the synergistic effects took place for RPM with EG, and the flame‐retardant mechanism has been changed in flame‐retardant HDPE/EVA/EG/RPM composites. The formation of stable and compact charred residues promoted by RPM acted as effective heat barriers and thermal insulations, which improved the flame‐retardant performances and prevented the underlying polymer materials from burning. POLYM. ENG. SCI., 55:2884–2892, 2015. © 2015 Society of Plastics Engineers