蒙脱土对膨胀型防火涂料阻燃性能的影响

采用锥形量热仪（CONE）研究蒙脱土（Na—MMT）对防火涂料阻燃性能的影响。结果表明，随着Na—MMT含量增加，膨胀型防火涂料的质量损失速率峰值（pk—MLR）和总耗氧量（TOC）相对于未添加蒙脱土的防火涂料降低，热释放速率峰值明显降低，热氧化降解推迟，热稳定性提高。对CONE燃烧过的膨胀型防火涂料进行扫描电镜（SEM）分析，添加了Na—MMT的体系炭层结构致密均匀，有效地防止了热量的散发。     

原位聚合法PS／蒙脱土复合材料燃烧性能的研究

采用原位聚合法分别制备了聚苯乙烯／有机蒙脱土（PS／OMMT）复合材料和聚苯乙烯／无机蒙脱土（PS／MMT）复合材料、用锥形量热仪测量测试了复合材料的燃烧性能，结果发现复合材料的热释放速率、质量损失速率、生烟速率等均显著降低，说明复合材料具有阻燃性。通过分析材料的燃烧性能和燃烧残余物，探讨了其可能的阻燃机理。还考察了原位聚合法对聚合转化率的影响。研究表明原位聚合法制备的PS／蒙脱土复合材料是一种阻燃效能高、环境友好且实际可行的阻燃体系。     

蒙脱土/SBR纳米复合材料阻燃性能的研究

采用熔融插层法制备蒙脱土／SBR纳米复合材料，并研究其阻燃性能。结果表明，SBR大分子不能有效插入钠基蒙脱土（Na—MMT）片层间，而能有效插入有机蒙脱土（OMMT）片层间，形成插层型纳米复合材料；将OMMT与高抗冲聚苯乙烯（HIPS）制成阻燃母粒能进一步提高SBR的插层效果。OMMT可以明显改善复合材料的阻燃和抑烟性能，随着OMMT用量的增大，复合材料的热释放速率、峰值热释放速率、平均热释放速率、总热释放和总生烟量先明显降低然后趋于稳定；HIPS-OMMT阻燃母粒可以明显改善复合材料阻燃性能，但对抑烟性能的改善效果不如OMMT。     

HPCTP/MMT复配阻燃环氧树脂阻燃及力学性能研究

将六苯氧基环三磷腈(HPCTP)与蒙脱土(MMT)复配,并以之为阻燃剂制备了阻燃环氧树脂。采用锥形量热仪对阻燃环氧树脂进行了燃烧测试,并对热释放速率、烟释放速率等数据进行了分析。结果表明,两种阻燃剂具有较好的协同阻燃效果,其中当MMT用量为1份时,热释放速率峰值(pk-HRR)下降了39.2%。力学测试表明,HPCTP的引入可以提升环氧树脂的拉伸性能,而同时加入1份的MMT可使体系的拉伸性能达到最佳,添加过量的MMT则会导致体系力学性能下降。     

SEBS／蒙脱土复合材料结构与阻燃性能的研究

根据蒙脱土（MMT）特殊的片层结构,采用熔融插层法制备热塑性弹性体SEBS／蒙脱土插层复合材料。通过X射线衍射仪、透射电镜等表征手段研究复合材料的微观结构。使用锥形量热仪评价复合材料的燃烧性能。结果表明,有机蒙脱土（OMMT）片层的间距为1．948nm,SEBS／5％OMMT体系的片层间距为4．307nm,说明聚合物SEBS插入有机蒙脱土片层之间。SEBS／OMMT复合材料具有较低的热释放速率和质量损失速率,且随着OMMT添加量的增加,其热释放速率峰值降低愈明显。通过对复合材料的阻燃性能和微观结构的分析,探讨了其阻燃机理。     

聚合物/层状纳米填料阻隔复合薄膜研究进展

综述了层状纳米复合材料的制备方法,以蒙脱土(MMT)、层状双氢氧化物(LDHs)和石墨烯(GNSs)为典型例子,系统阐述了层状纳米填料改善聚合物薄膜阻透性能的机理,最后讨论了高阻透、多功能化的纳米复合薄膜在制备及应用中所面临的挑战。     

阻燃聚苯乙烯/层状无机纳米复合材料的研究进展

综述了阻燃聚苯乙烯(PS)/蒙脱土(MMT)纳米复合材料、阻燃PS/双氢氧化物(LDH)纳米复合材料、阻燃PS/石墨烯(GO)纳米复合材料的阻燃性能和热稳定性能,利用添加型或反应型阻燃剂制备的上述3种复合材料的阻燃性能和热性能都有大幅度的提高。最后展望了阻燃PS/层状无机纳米复合材料的研究和应用前景。     

蒙脱土协效次膦酸盐阻燃ABS的研究

在二乙基次膦酸铝(AEP)和二乙基次膦酸三聚氰胺盐(MEP)复配阻燃ABS的基础上,加入少许蒙脱土(MMT)用作协效阻燃剂,所制备的阻燃ABS展现出良好的阻燃性能、力学性能和加工性能.当AEP/MEP/MMT质量比为8/5/1,添加质量分数为28%时,其阻燃ABS材料的氧指数可达37.1%,垂直燃烧时间仅为3 s,阻燃级别达到FV-O;且具有较高的拉伸强度和冲击强度.热失重、锥形量热仪和电镜等测试分析表明,蒙脱土有效抑制了热量传播,降低了热释放速率,改善了燃烧残余物的致密度,起到了良好的协效阻燃作用.     

聚甲基丙烯酸/蒙脱土纳米复合材料的制备及性能

用甲基丙烯酸(methacrylic acid,MAA)在钠基蒙脱土(montmorillonite,MMT)层间直接原位插层聚合制备了聚甲基丙烯酸/蒙脱土(polymethacrylic acid/montmorillonite,PMAA/MMT)纳米复合材料.以蒙脱土的层间距、插层进入蒙脱土层间的聚合物含量及应用于皮革鞣制的实验结果为考察指标,对制备过程中的引发剂用量及蒙脱土用量进行了单因素实验研究.结果表明:所制备的PMAA/MMT纳米复合材料属于剥离型纳米复合材料,应用于皮革鞣制所得坯革的增厚率及湿热稳定性均有较大提高.     

PP/纳米蒙脱土复合材料炭层结构对阻燃性能的影响

采用熔融插层法制备了不同纳米蒙脱土含量的聚丙烯(PP)/有机蒙脱土(OMMT)和PP/无机蒙脱土(MMT)复合材料,且评价了复合材料的阻燃性能:采用数码相机、扫描电子显微镜观察了燃烧残余物结构.加入OMMT可显著提高PP/OM MT的阻燃性能:纯PP的热释放速率(HRR)峰值为1 337.59 kW/m2;w(OMMT...     

In-situ growth of layered double hydroxide on montmorillonite nanosheets to improve the flame retardant performance of ABS resin

Layered double hydroxide (LDH) is a widely used flame retardant in polymer materials; however, the poor dispersion due to its high hydrophilic nature results in disappointing thermal stability and fire safety. In this work, LDH was in-situ grown on the disordered montmorillonite (MMT) nanosheets to obtain the hybrid of LDH and MMT nanosheets (LDH@MMT, simplified as LM). Various techniques, including X-ray diffraction, Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, and transmission electron microscope were used to characterize the microstructure of LM. In addition, the acrylonitrile-butadiene-styrene (ABS) composite containing LM and intumescent flame retardant (IFR) was prepared, and its mechanical and flame-retardant properties were also measured. The characterization results demonstrate that the LM exhibits a periodically alternating layered structure. The Limiting Oxygen Index (LOI) of the ABS composite reaches 27.2% with a V-0 rating in the UL-94 vertical burning test, while its flexural strength and tensile strength decrease by only 17.82% and 13.45%, respectively. Furthermore, the heat release rate, total heat release, smoke production rate, and carbon monoxide production rate of the ABS composite present a significant decline in cone calorimeter tests compared with those of pure ABS. The results further indicate that the hybridization could effectively improve the flame-retardant performance of ABS composites and perform lesser impacts on their mechanical properties.     

Synergistic flame retardant effects of Fe-OMMT with LDH in EVA/LDH composites

Abstract

The synergistic effects of Fe organic modified montmorillonite (Fe-OMMT) with layered double hydroxides (LDHs) in ethylene vinyl acetate copolymer/LDH (EVA/LDH) composites have been studied using thermal analysis [thermogravimetric analysis (TGA)], limiting oxygen index (LOI), UL-94 test and cone calorimeter test (CCT). The results showed that the addition of a given amount of Fe-OMMT apparently increased the LOI value and the rating in the UL-94 test. The results from the LOI and UL-94 tests show that Fe-OMMT can act as flame retardant synergistic agents in EVA/LDH composites. The CCT data indicated that the addition of Fe-OMMT in the EVA/LDH system can greatly reduce the heat release rate. The TGA data show that Fe-OMMT, as an excellent flame retardant synergist of LDH, cannot increase the thermal degradation temperature and the charred residues.     

Nickel-Aluminum Hydrotalcite for Improving Flame Retardancy and Smoke Suppression of Intumescent Flame Retardant Polypropylene: Preparation,Synergy, and Mechanism Study

Intumescent flame retardants (IFR) are widely used in the field of flame retardant polypropylene (PP), but their flame retardant efficiency and smoke suppression properties need to be further improved. Herein, a Ni-Al LDH (layered double hydroxide) is obtained successfully by coprecipitation and microwave hydrothermal technique and used as a synergist to improve the flame-retardant and smoke-suppression properties of triazine-based IFR. The results showed that IFR/Ni-Al LDH exhibited the best synergistic effect when the IFR is replaced by 5 wt% Ni-Al LDH. 17 wt% IFR/Ni-Al LDH enabled the PP composites to achieve UL-94 V-0 rating with a high LOI of 29.8%. Besides, the introduction of Ni-Al LDH effectively decreased the heat and smoke release of the PP/IFR composites due to its catalytic charring effect. This is mainly attributed that the introduction of metal ions in Ni-Al LDH effectively improved the strength and crosslinking degree of char layer and promoted the formation of a cohesive and dense char layer. The formed high-quality char layer effectively exerted the barrier effect in condensed phase. Therefore, the PP/IFR/Ni-Al LDH composites exhibited excellent flame-retardant and smoke-suppression performance. This investigation provided a facile way to prepare environment-friendly and high-performance flame retardant PP composites with wide application prospects.     

Layer double hydroxide and sodium montmorillonite multilayer coatings for the flammability reduction of flexible polyurethane foams

Flexible polyurethane foam (PUF) is coated by layer‐by‐layer (LbL) assembly using branched polyethyleneimine (BPEI), poly(acrylic acid) (PAA), and two different charged nanoparticles, such as sodium montmorillonite (Na‐MMT) and layered double hydroxide (LDH). Three different deposition strategies, that is, bilayer, trilayer, and quadlayer, exhibit different coating growth, morphology, and flammability properties. Changing the nanosheet from LDH to MMT dramatically alter the coating mass for the same number of layers. A five bilayer PAA/BPEI+LDH coating reduced the peak heat release rate by 40% and the average heat release rate by 70%, which is two times more effective than commercial fire retardants (FRs) and other LbL‐FR coatings for PUF. MMT and LDH mixed multilayers resulted in effective flame‐retardant coatings with less coating mass by manipulating the deposition strategy. This study manifests the flexibility of LbL to fine‐tune flammability reduction by switching the coating weight gains, which is significant to accelerate the development of other LbL coating regardless of the intended applications. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41767.     

Thermal Properties and Flammability of Ethylene-Vinyl Acetate Copolymer/Montmorillonite/Polyethylene Nanocomposites with Flame Retardants

Ethylene-vinyl acetate copolymer (EVA)/montmorillonite (MMT) composite was blended with a linear low density polyethylene (LLDPE). X-ray diffraction and transmission electron microscopy (TEM) image of the EVA/MMT composite are in support of an intercalated with partially delaminated nanocomposite. The tensile strength of the nanocomposite is about 20% higher than that without layered silicates, MMT. Furthermore, the incorporation of MMT into polymer blend delays the main thermo-oxidative degradation. Cone calorimeter test points out that the addition of layered silicates into the pristine EVA/LLDPE blend or the blend with a low smoke non-halogen (LSNH) fire retardants, aluminum trihydroxide, and antimony trioxide, can reduce the maximum heat release rate by 30–40%. The smoke suppressing effect of layered silicates is only observed in the nanocomposite containing flame retardants. According to the limiting oxygen index (LOI) data and cone calorimeter test, the addition of the nanodispersed layered silicate and LSNH flame retardants to the EVA/LLDPE exhibits a synergistic effect on the flame retardancy and smoke suppression.     

Preparation of aluminum diethyl hypophosphite intercalation-modified montmorillonite AlPi-MMT and its effect on the flame retardancy and smoke suppression of thermoplastic polyester elastomer

An aluminum diethyl hypophosphite intercalation-modified montmorillonite flame retardant (AlPi-MMT) is successfully prepared and characterized by FT-IR, SEM, and X-ray diffraction. It is found that thermoplastic polyester elastomer (TPEE) composites incorporating 15 wt% AlPi-MMT flame retardant exhibited better char formation and flame retardant properties compared to those incorporating 15 wt% (4:1, w:w) AlPi and MMT. And the char residual of TPEE/AlPi-MMT at 700°C is 16.17%, which is higher than that of TPEE/AlPi-MMT at 13.94%. and the former can pass UL-94 V-0 rating test while the latter can only pass UL-94 V-1 rating test. Afterwards, the combustion performance of TPEE composites is characterized, and it is found that the heat release and smoke release of TPEE/AlPi-MMT are greatly reduced compared with those of pure TPEE and TPEE/AlPi/MMT, which is a flame retardant and smoke suppressant TPEE composite. Finally, by analyzing the residual char morphology and elements of TPEE composites after combustion, the mechanism of the flame retardant AlPi-MMT to promote char formation and flame retardancy is demonstrated.     

蜜胺-环氧树脂双层包覆聚磷酸铵及其阻燃PP的研究

针对聚磷酸铵(APP)耐水性不足、与聚丙烯(PP)等高分子材料相容性差等问题，采用甲醛-三聚氰胺(蜜胺树脂)和环氧树脂双层包覆了APP(EM-APP)，采用红外、扫描电镜、热重分析、溶解度测试等方式表征了包覆效果；采用水平垂直燃烧、氧指数仪和锥形量热仪、热重-红外联用等设备考察了包覆APP用于阻燃PP的效果，探讨了阻燃机理。结果表明：包覆操作不但有效提高了APP的耐水性，且将具有成炭功能的包覆层引入到APP表面；EM-APP相较APP，800℃时残炭量提高14.2%，在聚丙烯中加入同样质量份时，前者具有更高的阻燃效率，热释放速率、总热释放量、烟释放速率和总烟释放量都明显降低；包覆改善了APP与PP的相容性；燃烧过程中包覆层起到了协同成炭的作用。     

Synergistic flame retardant effects of ammonium polyphosphate in ethylene‐vinyl acetate/layered double hydroxides composites

Mg–Al–Fe ternary layered double hydroxides (LDH) were synthesized based on bayer red mud by calcination‐rehydration method, and characterized using X‐ray diffraction and thermogravimetric analysis (TGA). The synergistic flame retardant effects of ammonium polyphosphate (APP) with LDH in ethylene‐vinyl acetate (EVA) composites were studied using limiting oxygen index (LOI), UL 94 test, cone calorimeter test (CCT), and smoke density test (SDT). The thermal degradation behavior of EVA/LDH/APP composites was examined by thermal gravimetric analysis‐fourier transform infrared spectrometry (TG‐FTIR). The results showed that LOI values decreased by incorporation of APP together with LDH; and, a suitable amount of APP in EVA/LDH composites can apparently improve UL 94 rating. The CCT results indicated that heat release rate (HRR) of the EVA/LDH/APP composites with APP decreased in comparison with that of the EVA/LDH composites. The SDT results showed that APP was helpful to suppress smoke. The TG‐FTIR data showed that the composites with APP had a higher thermal stability than the EVA/LDH composites at high temperature. POLYM. ENG. SCI., 54:766–776, 2014. © 2013 Society of Plastics Engineers     

Synergistic Flame Retardant Effects of Carbon Nanotube-Based Multilayer Nanocoatings

In an effort to develop highly functionalized flame retardant materials, hybrid nanocoatings are prepared by alternately depositing a positively charged polyaniline (PANi) and negatively charged montmorillonite (MMT) using the layer-by-layer (LbL) assembly technique. Carbon nanotubes (CNTs) are employed in polymer nanocomposites as effective reinforcement, where nanotubes are stabilized in MMT aqueous solution. The 3D structure and high density of CNTs deposited in the PANi/CNTs-MMT multilayers produce thicker and heavier coatings in comparison to the LbL assemblies without CNTs. Vertical and horizontal flame testing show that the incorporation of CNTs improves fire resistance. Additionally, cone calorimetry reveals that stacking two nanomaterials (MMT and CNTs) in a single coating shows a significant reduction in peak heat release rate (up to 51%), total smoke release (up to 47%), and total heat release (up to 37%) for the polyurethane foam. The enhancement of flame retardancy is attributed to a synergistic effect; MMT serves as a physical barrier that retards the diffusion of heat and gas. The addition of CNTs strengthens the thermal stability and high char yield. These results, coupled with the simplicity with which the LbL deposition is applied, present a viable alternative to halogen-free flame retardant nanocoatings to natural and synthetic fibers.     

Superior thermal stability and smoke suppression of epoxy resin composites with graphene/LDH phosphorus-rich hybrids

In this article, graphene/LDH phosphorus-rich triple hybrid was prepared by a mild method and used to effectively improve the thermal stability and smoke suppression of epoxy resin (EP). The graphene was firstly reacted with hexamethylenediamine (HA) and followed by the treatment with the layered double hydroxide (LDH) and NaH₂PO₄ solutions. Compared to the unmodified graphene, the initial decomposition temperature of the triple hybrids increases significantly from 168.6 to 292.5°C. The residual carbon content is greatly improved and the residual mass is up to 84.1%. Elemental analysis reveals the content of phosphorus in EP composites is as high as 10 wt%. In flame retardancy tests, the peak heat release rate of the EP composite with 5 wt% graphene/LDH phosphorus-rich hybrids decreases to 786.15 KW/m², 41.19% drastic reduction compared to that of EP. These results indicate that the triple functionalization process effectively expands the interval distribution of heat release and makes the heat release process more gradual and spread flames smaller. The smoke production rate and total smoke production rate of EP composite with 5 wt% graphene/LDH phosphorus-rich hybrids are 0.32 m²/s and 40.91 m², which are significantly reduced by 65.22 and 57.83%, respectively. This gentle and efficient process provides a new approach to multi-functional design to improve the thermal stability and smoke suppression of resin-based composites.