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利用锥形量热仪(CONE)在35kW/m2热辐照条件下,并结合极限氧指数(LOI)和UL-94垂直燃烧测试方法对聚丙烯(PP)/乙烯-醋酸乙烯酯共聚物(EVA)/有机蒙脱土(OMMT)纳米复合材料和加入无卤复配阻燃剂制备的PP/EVA/OMMT/氢氧化铝(ATH)/三氧化二锑(AO)纳米复合阻燃材料的热释放速率、烟释放及材料在燃烧时的质量损失行为进行了研究。结果表明,添加5%(质量分数)OMMT可以提高PP/EVA复合材料的阻燃性能,燃烧时的热释放速率、质量损失率以及烟释放量减少,且OMMT与无卤复配阻燃剂之间可产生阻燃协同作用,使纳米复合阻燃材料的阻燃性能、热稳定性和抑烟性进一步增强。 相似文献
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分别介绍了采用金属氢氧化物阻燃剂、蒙脱石型阻燃剂、磷系阻燃剂、氮系阻燃剂、膨胀型阻燃剂、有机硅阻燃剂、碱式硫酸镁晶须(MOS)阻燃剂和辐射交联技术制备的无卤阻燃乙烯―乙酸乙烯共聚物(EVA)复合材料的研究开发现状,并展望了无卤阻燃EVA复合材料的发展趋势。 相似文献
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将三聚氰胺氰尿酸盐(MCA)阻燃剂添加到玻纤增强的尼龙66复合材料(GF-PA66)中。利用UL-94实验对MCA在复合材料中的阻燃效果进行研究;通过扫描电子显微镜(SEM)分析了燃烧后的样品形貌,并利用热重分析法对复合材料的热分解行为进行了研究。结果表明:MCA可使玻纤增强尼龙66复合材料达到UL-94V-0级阻燃效果;MCA晶体被均匀地分散于尼龙基体中,在燃烧时MCA通过自身吸热分解,产生不可燃气体,实现气相阻隔,从而起到阻燃作用,并在复合材料自熄面上留下纳米级气孔。 相似文献
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采用原位聚合法合成制备了以蜜胺树脂(MF)、环氧树脂(EP)以及EP和MF为囊材的微胶囊阻燃剂MFAPP、EPAPP、EMFAPP,用红外光谱(FT-IR)和扫描电镜(SEM)表征微胶囊阻燃剂的核壳结构。采用极限氧指数(LOI)和垂直燃烧等级测试(UL94)对MFAPP、EPAPP、EMFAPP在环氧树脂中的阻燃特性进行了研究。当添加量大于7%时,阻燃复合材料均能通过UL 94 V-0级测试,极限氧指数大于27.0%,表明MFAPP、EPAPP、EMFAPP均为EP的高效阻燃剂,这些阻燃剂在EP阻燃过程中均形成了膨胀炭层,属于膨胀阻燃机理。另外在耐水性实验中发现,添加EPAPP、EMFAPP的EP复合材料具有更好的耐水性,经75℃水浸泡6天后,阻燃性能得到了较好的保持。 相似文献
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以4,4'-二羟甲基-1,4-庚二炔功能单体作为扩链剂制备了端炔基功能化聚氨酯, 与叠氮基改性纳米蒙脱土(MMT-N3)、 纳米氢氧化铝(ATH-N3)和纳米氢氧化镁(MH-N3)通过Click反应制备了水性聚氨酯(WPU)阻燃纳米复合材料. 采用红外光谱(FTIR)、 核磁氢谱(1H NMR)和扫描电子显微镜(SEM)对WPU阻燃纳米复合材料的结构进行了表征, 对比研究了纳米阻燃剂配比和制备方法对WPU阻燃纳米复合材料的氧指数、 动态燃烧行为和热稳定性的影响. 阻燃性能研究结果表明, 当MMT-N3, MH-N3和ATH-N3的质量分数分别为7%, 2%和1%时, 采用Click反应制备的复合材料的氧指数比纯WPU高7%, 点燃时间从10 s延长到29 s, 峰值热释放速率和烟释放速率分别降低了41%和42%. 热失重分析结果表明, 当MMT-N3质量分数为10%时, 与WPU相比, 采用Click反应制备的MMT/WPU复合材料在热失重50%时的温度提高了21 ℃. 复合材料断面和燃烧后残渣的SEM分析证明在聚合物基体中Click反应是分散纳米材料的一种有效方法. 相似文献
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《高分子通报》2017,(2)
利用锥形量热仪(CONE)和热重分析(TGA),并结合极限氧指数(LOI)和UL-94垂直燃烧测试方法对核(PSt/OMMT)-壳(PBA)结构纳米复合粒子(CSN)填充聚丙烯(PP)-乙烯-醋酸乙烯酯共聚物(EVA)复合材料及加入无卤复配阻燃剂制备的PP-EVA/CSN/聚磷酸铵(APP)/层状氢氧化镁铝(LDH)复合阻燃材料的阻燃性能及热降解行为进行了研究。结果表明,添加10%(wt)CSN可以提高PP-EVA复合材料的阻燃性能,且PP-EVA复合体系燃烧时的热释放速率、有效燃烧热减少,热稳定性增强。CSN与APP/LDH产生阻燃协同作用,使复合阻燃材料的阻燃性能、热稳定性能进一步提高。 相似文献
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碳纳米材料是一类推动能源存储、 多相催化、 高性能复合和生物医药等领域发展的重要材料, 可控合成碳纳米材料对相关领域的发展具有重要意义. 水滑石(LDHs)材料具有层板金属种类及含量可调等特点, 经焙烧、 还原后可制备出金属种类、 密度和粒径分布各异的高分散、 高稳定金属纳米催化剂, 可实现高效催化生长各种类型的碳纳米材料. 此外, 通过调控反应条件和反应器等, 可以影响LDHs基金属纳米催化剂催化生长的碳纳米材料的结构和性能. 本文总结了LDHs基金属纳米催化剂的可控制备、 碳纳米材料结构调控以及利用LDHs基催化剂制备的碳纳米材料的应用等方面的研究工作, 并阐明了催化剂的可控制备是控制合成碳纳米材料的核心手段, 这为利用LDHs基催化剂进一步合成更高性能碳纳米材料的研究指明了方向. 此外, 本文还结合近些年在光、 电及光热催化方面的研究进展, 展望了基于新型LDHs纳米结构生长碳纳米材料的研究前景. 相似文献
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He S Zhang S Lu J Zhao Y Ma J Wei M Evans DG Duan X 《Chemical communications (Cambridge, England)》2011,47(38):10797-10799
A ZnO nanocatalyst with a high percentage exposure of (0001) facets embedded on a hierarchical flower-like matrix has been prepared by an in situ topotactic transformation of a layered double hydroxide precursor, and exhibits significantly higher visible light photocatalytic performance than other ZnO nanomaterials with fewer exposed (0001) facets. 相似文献
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In this work, ordered vertical arrays of layered double hydroxide (LDH) nanosheets have been developed to achieve electron transfer (eT) at biointerfaces in electrochemical devices. It is found that tailoring the gap size of LDH nanosheet arrays could significantly promote the eT rate. This research has successfully extended nanomaterials for efficient modifications of electrode surfaces from nanoparticles, nanowires, nanorods, and nanotubes to nanosheets. 相似文献
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片状二维镍纳米材料具有较高的形状各异性,在催化、磁记录以及生物探测方面具有重要的应用价值,因此寻找一种简单,成本低的方法制备表面无活性剂的片状镍纳米材料显得尤为重要。在没有有机表面活性剂和形貌控制剂的条件下,在氟掺杂氧化铟锡(FTO)导电玻璃表面,通过水热制备得到金属镍纳米薄片。系统地研究了反应条件对产物形貌的影响,发现镍源、氢氧化钠、氨水的浓度以及反应温度对纳米镍的形貌有较大的影响。只有在合适的氨水和氢氧化钠浓度共同存在下,才能获得具有较大的特征长度以及较薄的近二维结构的六边形镍金属钠米薄片。经过条件优化,制备得到的厚度约为10 nm,横向特征长度超过1μm金属镍纳米薄片。经过分析认为,体系的p H值及温度影响了反应速度,最终导致产物的形貌受到影响,在p H值约为10的条件下,氨水对镍离子的络合作用对镍纳米薄片的二维生长具有一定的促进作用。 相似文献
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A galvanic replacement reaction was used to prepare silver–platinum bimetallic nanowires and platinum nanotubes. Silver nanowires,
prepared by boiling aqueous silver nitrate with sodium citrate in the presence of small amount of sodium hydroxide, were used
as the sacrificial template in the galvanic reaction to prepare silver–platinum bimetallic nanowires and ultimately hollow
platinum nanotubes. The resulting nanomaterials are stable and can be isolated without core aggregation or decomposition.
These new materials have been characterized by transmission electron microscopy, energy dispersive X-ray analysis, and inductively
coupled plasma atomic emission spectroscopy. 相似文献
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Growth and surface properties of boehmite nanofibers and nanotubes at low temperatures using a hydrothermal synthesis route 总被引:2,自引:0,他引:2
Zhao Y Frost RL Martens WN Zhu HY 《Langmuir : the ACS journal of surfaces and colloids》2007,23(19):9850-9859
The growth of boehmite nanostructures at low temperature using a soft chemistry route with and without (PEO) surfactant is presented. Remarkably long boehmite 1D nanotubes/nanofibers were formed within a significantly short time by changing the reaction mechanism of aluminum hydroxide. By using the PEO surfactant as a templating agent, boehmite nanotubes up to 170 nm in length with internal and external diameters of 2-5 and 3-7 nm, respectively, were formed at 100 degrees C. A slightly higher temperature (120 degrees C) resulted in the formation of lath-like nanofibers with an average length of 250 nm. Using the cationic surfactant CTAB, nanotubes rather than nanofibers were formed at 120 degrees C. Without surfactant, nanotubes counted for around 20% of the entire sample. A regular interval supply of fresh boehmite precipitate resulted in a larger crystallite size distribution of nanotubes. The morphology of nanotubes was more uniform in samples without the regular addition of aluminum hydroxide. Moreover, for the same hydrothermal time, the final nanotubes for nanomaterials without a regular interval supply of fresh aluminum hydroxide precipitate were longer than those with a regular aluminum hydroxide precipitate supply, which is in contrast to previously published results. Higher Al/PEO concentrations resulted in the formation of shorter nanotubes. A detailed characterization and mechanism are presented. 相似文献
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Sea-urchin-like ZnO nanomaterials were successfully synthesized by decomposition of zinc acetate precursor in the presence of sodium hydroxide and ethylene glycol(EG) in an ethanol solution using a solvothermal method at 180 ℃ for 12 h.The crystalline phase and morphology of the resultant nanomaterials were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),selected-area electronic diffraction(SAED) and high-resolution electron microscopy(HRTEM).Interestingly,the sizes and prod length of the samples can be easily tuned by changing the amount of directing agent EG and keeping other reaction conditions unchangeable.On the basis of our experimental outcomes,EG-controlled-nucleation-growth formation mechanism was proposed to correspond for the sea-urchin-like ZnO growth processes.And the photoluminescence(PL) spectra of the as-selected samples were measured at room temperature,presenting two emission peaks centered at~388 and 480 nm. 相似文献
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Zhiquan Chen Mengwei Jiang Yuan Yu Guangping Sun Juncheng Jiang 《International Journal of Polymer Analysis and Characterization》2017,22(6):509-518
A series of flame-retardant unsaturated polyester resin (UPR) were prepared by the addition of dimethyl methylphosphonate (DMMP) with various amounts of aluminum hydroxide (ATH) or ammonium polyphosphate (APP) as the flame retardants. The combustion resistance effects of ATH/DMMP and APP/DMMP systems were evaluated by limiting oxygen index test and vertical burning test (UL-94). The thermal properties of UPR were investigated by thermogravimetric analysis. The structure of char was observed by scanning electron microscopy. DMMP incorporated with ATH or APP improved the flame retardancy and thermal properties of UPR. However, the fire-retardant mechanism of these two systems were different: The ATH/DMMP system provided synergistic effect in charring property of the UPR, produced great amount of residual char, and thus revealed the excellent flame retardancy. The APP/DMMP system further improved the flame retardancy of the UPR due to the change in the residual char structure rather than the increase in the production of char. 相似文献
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Performance of intumescent fire retardant for wood 总被引:1,自引:0,他引:1
Performance characteristics of new fire-retardant formulations are studied, including their water resistance and the effect of additives. 相似文献