防火硅橡胶材料的研制

采用正交试验设计方法,考察了以有机改性蒙脱土(OMMT)、硼酸锌、硅酸铝纤维和气相法二氧化钛组成的阻燃防火体系对硅橡胶氧指数、最高背面温度和密度等的影响。结果表明:OMMT、硼酸锌、硅酸铝纤维和气相法二氧化钛对硅橡胶具有很好的阻燃防火协同效应,当硅橡胶/OMMT/硼酸锌/硅酸铝纤维/气相法二氧化钛用量比为100/5/30/20/10时,防火硅橡胶具有良好的综合性能。     

NiPd/TiO2催化剂的制备及其催化甲酸分解制氢性能

高效、清洁且无毒无害的催化剂是实现以甲酸(HCOOH)为化学储氢材料分解制氢的重点。本文采用水热法在453K的条件下制备TiO₂载体,再通过浸渍法向其中加入总量为0.1 mmol的NiCl₂.6H₂O和K₂PdCl₄金属溶液,将活性组分Ni、Pd负载到TiO₂载体上合成NiPd/TiO₂催化剂,并探究其对催化甲酸分解制氢的性能的影响。探究结果表明,在光照条件下,NiPd/TiO₂催化剂中,当金属Ni:Pd比例为2:8时,催化剂的反应转化频率(TOF)值最大,此时催化剂的 TOF 为3528 h_-1^,且该催化剂上甲酸分解的活化能(E_a)为53.9 kJ/mol。关键词：镍钯催化剂;甲酸;分解制氢;二氧化钛;光照中图分类号：TQ630 文献标识码： A 文章编号：     

ZnB对LGFPP/IFR阻燃体系性能的影响

通过熔融共混法制备了长玻纤增强聚丙烯/膨胀阻燃剂/硼酸锌(LGFPP/IFR/ZnB)复合材料,并测定了其阻燃性、热稳定性及力学性能;通过扫描电镜(SEM)观察燃烧后的微观形貌,考察了ZnB对LGFPP/IFR阻燃体系性能的影响。结果表明:适当用量的ZnB与IFR阻燃剂具有协同阻燃作用,可提高LGFPP/IFR体系的阻燃性、热稳定性及力学性能。在LGFPP/IFR阻燃体系中添加2%的ZnB,LGFPP/IFR/ZnB复合材料的氧指数提高到23.6%;拉伸强度、弯曲强度和冲击强度分别提高了10.7%、15.1%和31.9%。     

ML-WO3/TiO2异质结的制备及其对罗丹明B的光催化降解

采用空间限域法制备了单层三氧化钨纳米片(ML-WO₃),然后将其与TiO₂复合得到ML-WO₃/TiO₂纳米材料,被用来在模拟太阳光下对罗丹明B进行光催化降解。ML-WO₃/TiO₂的组成和光学特性通过扫描电镜、透射电镜、高分辨透射电镜、X射线衍射、紫外-可见吸收光谱和光致发光光谱手段进行表征。结果证实,纳米ML-WO₃/TiO₂克服了纯TiO₂带隙较大的缺陷,在全波段太阳光表现出比ML-WO₃和TiO₂更强的吸收性能,ML-WO₃与TiO₂之间具有明显的协同效应。活性物种捕获实验表明.OH和.O_2^-自由基是RhB降解的主要活性物种。ML-WO₃和TiO₂之间构建的Z型异质结电荷转移路径能够保证光生载流子的高效分离和重组。在5次循环实验后ML-WO₃/TiO₂的光催化活性仍能接近80%,具有良好的光化学稳定性。通过高效液相色谱-质谱检测RhB的中间产物,推测了RhB可能的降解路径。     

Influence of MPP and OMMT based synergistic flame retardant on silicone rubber performance

以三聚氰胺磷酸盐(MPP)、有机蒙脱土(OMMT)为协效阻燃剂制备阻燃硅橡胶.通过X射线衍射(XRD)法、垂直燃烧法、热重法(TG)等研究阻燃硅橡胶分散性、燃烧性能和拉伸性能.结果表明,OMMT与MPP具有明显协同阻燃性;当OMMT用量为3质量份、MPP用量为55质量份时,复合材料有焰燃烧时间最短,阻燃效果最好;OMMT用量为3～5质量份时,复合体系的垂直燃烧性能均可达到FV -0级,残碳率最高,且力学性能较好.     

尼龙6/弹性体合金的阻燃改性研究

分别采用环保阻燃剂十溴二苯乙烷(DBPE)/三氧化二锑(Sb2O3)和聚磷酸铵(APP)对PA6/POE-g-MAH合金进行阻燃改性,同时以纳米有机蒙脱土(OMMT)作为辅助阻燃剂,讨论了阻燃剂种类、用量和配比对合金燃烧性能和力学性能的影响.结果表明:DBPE/Sb2O3在该体系中具有比APP更高的阻燃效率;OMMT与DBPE/Sb2O3和APP在合金的阻燃改性方面具有一定的协同效应;所有阻燃成分对合金的韧性均产生负面影响;DBPE/Sb2O3和APP使得体系的拉伸强度下降,而OMMT发挥了一定的补强作用;当DBPE/Sb2O3与APP组成的复配阻燃体系中二者的用量分别为10份和40份时,合金具有较好的综合性能.     

MP/OMMT对脱醇型RTV阻燃硅橡胶性能的影响

以α,ω-二羟基聚二甲基硅氧烷(107硅橡胶)、甲基三乙氧基硅烷、三聚氰胺磷酸盐(MP)和纳米有机蒙脱土(OMMT)为原料,制备了脱醇型室温硫化(RTV)阻燃硅橡胶。研究了MP/OMMT配比对脱醇型RTV硅橡胶阻燃性能、动态燃烧性能和机械性能、热稳定性的影响,用扫描电镜(SEM)考察了MP、OMMT在RTV硅橡胶中的分散情况。锥形量热仪和极限氧指数测试结果表明,随着OMMT用量的增多和MP用量的减少,硅橡胶的阻燃性能没有显著的变化;热失重分析表明,OMMT的添加使硅橡胶的初始分解温度明显提高,大大提高了硅橡胶燃烧残渣的生成量;机械性能测试表明,OMMT的增多能明显提高硅橡胶的机械性能。与只添加MP的硅橡胶相比,当MP和OMMT各添加20份时,硅橡胶的极限氧指数下降0.6%,初始分解温度提高了95℃,拉伸强度、硬度、撕裂强度分别提高48.6%、4.7%、50.9%;此时的SEM分析表明,OMMT能在硅橡胶中均匀分散,且燃烧残渣表面变得平整、坚硬、致密。即在此配比下硅橡胶能在保持良好阻燃性的同时提高其机械性能。     

基于WO3-MoO3和TiO2/CdS复合电极的光电致变色器件

电致变色广泛应用于智能窗领域,但电致变色材料仍需外部电源驱动,将太阳能电池与电致变色材料结合起来的光电致变色器件可实现无需外部供电的智能变色调控。性能优异的变色阴极和光阳极是当下光电致变色器件的研究热点。通过水热法制备WO₃-MoO₃薄膜,研究其电致变色性能;通过水热法结合连续离子层沉积法制备TiO₂/CdS复合薄膜,研究其光电转换性能。最后将WO₃-MoO₃薄膜和TiO₂/CdS复合薄膜分别作为光电致变色器件的变色阴极、光阳极构建WO₃/MoO₃-TiO₂/CdS光电致变色器件。WO₃/MoO₃-TiO₂/CdS光电致变色器件具有较大的光学调制范围(630nm处为41.99%)、更高的着色效率(35.787%),将其作为智能窗应用在现代建筑、通行工具等领域具有重要应用价值。     

聚磷酸铵阻燃体系对HIPS/OMMT阻燃研究

将钠基蒙脱土(Na~ -MMT)有机化改性,制成有机蒙脱土(OMMT),采用熔融插层法分别制备HIPS/OMMT复合材料和聚磷酸铵(APP)体系阻燃的HIPS/OMMT复合材料。结果表明,HIPS/OMMT复合材料具有一定的阻燃性能,但阻燃性能的提高比较有限;与仅添加OMMT时相比,APP体系阻燃的HIPS/OMMT复合材料的阻燃性和抑烟性均得到进一步提高,以APP、季戊四醇(PER)和硼酸锌(ZB)为膨胀型阻燃剂对HIPS/OMMT复合材料阻燃性和抑烟性的提高更为显著。力学性能测试结果表明,APP体系的加入对复合材料的拉伸强度和冲击强度都有负面影响。     

致密油藏CO2驱响应性防窜体系的制备及性能

以3-二甲胺基丙胺和油酸为主剂制备具有叔胺结构的CO₂响应性单体N,N-二甲基油酸酰胺丙基叔胺(DOAPA),将其与有机反离子互配构建具有CO₂响应性的蠕虫状胶束(CO₂-TWMS)。通过体系与CO₂接触前后的电导率、化学结构和微观形貌变化表征体系的响应性,结合体系表面活性变化及致密基质/裂缝双重介质CO₂驱替与CO₂-TWMS防窜过程中的压力和采收率变化揭示CO₂-TWMS防窜性能与机制。实验结果表明,当反离子为对甲苯磺酸钠,与DOAPA的摩尔比为1:1时,CO₂-TWMS体系的黏度最大。CO₂和N₂能够刺激体系电导率在0.9ms/cm和1.95ms/cm之间可逆变化、诱导微观形貌在蠕虫状胶束和球形胶束间转换。此外,CO₂能够将体系临界胶束浓度从1mmol/L降低至0.25mmol/L,最低表面张力从30.2mN/m降低至29.1mN/m,体系在气液界面的吸附效率和效能增强,有利于胶束的形成。在致密基质-裂缝双重介质中,CO₂诱导蠕虫状胶束形成,增大驱替过程中的压差,扩大CO₂驱替波及效率,采收率提高22.6%。     

Thermal reproducibility and voltage stability of carbon black/multiwalled carbon nanotube and carbon black/SnO2‐Sb coated titanium dioxide filled silicone rubber heaters

Flexible heaters were prepared by extruding platinum‐catalyzed silicone rubber (SR) compound with carbon black (CB)/multiwalled carbon nanotube (MWNT) and CB/SnO₂‐Sb coated titanium dioxide (TiO₂). MWNT with average particle length of 20 μm and acicular shaped TiO₂ with average particle length of 1.7 μm were selected. Thermal aging and mechanical deformation stability were compared for SR/CB, SR/CB/MWNT, and SR/CB/TiO₂ composites system. During thermal aging, conductor resistivity decreased because of the toughening effect of SR matrix. When 1 wt % of MWNT and TiO₂ were added into SR/CB compound, the deformation stability increased significantly. Thermal reproducibility and voltage stability of the extruded heaters were also investigated by applying AC voltage of 220 V. The heaters containing MWNT exhibited poor thermal reproducibility and voltage stability compared with heater containing TiO₂ or unfilled. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation of an organomontmorillonite master batch and its application to high‐temperature‐vulcanized silicone‐rubber systems

N,N‐Di(2‐hydroxyethyl)‐N‐dodecyl‐N‐methyl ammonium chloride was used as an intercalation agent to treat Na⁺‐montmorillonite and form a novel type of organic montmorillonite (OMMT). An OMMT master batch (OMMT‐MB) was prepared by solution intercalation and was used in the preparation of high‐temperature‐vulcanized silicone rubber (HTV‐SR)/OMMT‐MB nanocomposites. The properties, such as the tensile and thermal stability, were researched and compared with those of composites directly incorporated with OMMT or aerosilica. A combination of Fourier transform infrared spectroscopy, wide‐angle X‐ray diffraction, and transmission electron microscopy studies showed that HTV‐SR/OMMT‐MB composites were on the nanometer scale, and their structure was somewhat hindered by the presence of OMMT. The results showed that the tensile properties of HTV‐SR/OMMT‐MB and HTV‐SR/OMMT systems were better than those of pure HTV‐SR. Compared with those of HTV‐SR/OMMT‐20%, the tensile strength and elongation at break of HTV‐SR/OMMT‐MB‐20% were improved about 1.5 and 0.9 times, respectively. This was probably due to the nanoeffect of the exfoliated silicate layers. Moreover, the tensile strength of HTV‐SR/OMMT‐MB‐20% was nearly equal to that of HTV‐SR/aerosilica‐20%, and the elongation at break even showed much improvement. Additionally, the thermal degradation center temperature of the HTV‐SR/OMMT‐MB‐20% nanocomposite was increased by 30°C compared with that of the HTV‐SR/OMMT‐20% composite. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis of hyperbranched organo‐montmorillonite and its application into high‐temperature vulcanizated silicone rubber systems

N,N‐Di(2‐hydroxyethyl)‐N‐dodecyl‐N‐methyl ammonium chloride was used as intercalation agent to treat Na⁺‐montmorillonite and form a type of organic montmorillonite (OMMT). Hyperbranched OMMT (HOMMT) was prepared by condensation reaction between OMMT and the monomer we synthesized. It was then used in the preparation of high‐temperature vulcanizated silicone rubber (HTV‐SR)/HOMMT nanocomposite. Different types of HTV‐SR/HOMMT nanocomposites were prepared with different amounts of HOMMT and compared with the composites directly incorporated with OMMT. Tensile properties such as tensile strength, elongation at break, permanent distortion, and shore A hardness were researched and compared. A combination of Fourier transform infrared spectroscopy, wide angle X‐ray diffraction, and transmission electron microscopy studies showed that HTV‐SR/HOMMT composites were on the nanometer scale, and the structure of HTV‐SR was not interfered by the presence of HOMMT. Results showed that the tensile properties of HTV‐SR/HOMMT systems were better than that of the HTV‐SR/HOMMT and HTV‐SR. This was probably due to the surface effect of the exfoliated silicate layers and anchor effect of HOMMT in the SR matrix. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

有机蒙脱土／硅橡胶膜的制备及吸水性能研究

采用不同碳链长度的季铵盐作为插层剂改性钠蒙脱土,以硅橡胶为基体,用溶液插层法制备有机蒙脱土／硅橡胶纳米复合材料。系统分析了有机蒙脱土对硅橡胶吸水性能的影响,包括胶膜吸水性和吸水后的力学性能。通过X射线、红外表征了有机蒙脱土的结构。实验结果袁明,烷基碳原予数越多,所制备的有机蒙脱土／硅橡胶纳米复合材料对水的阻隔性越好;当蒙脱土质量分数为3％时,吸水性最低,吸水后力学性能下降幅度最小。     

Preparation,characterization, and property testing of condensation‐type silicone/montmorillonite nanocomposites

Nanocomposites (NCs) of silicone rubber and organically modified montmorillonite (OMMT) nanoparticles were prepared and characterized. It was shown that OMMT loadings of 2 and 3.5 parts per hundred resin/filler per weight (phr) produced exfoliation or delamination hybrids, whereas at a concentration of 5 phr, the filler seemed to retain its original crystallographic morphology, and the system shifted to an ordinary reinforced elastomer. Fourier transform infrared analysis, differential scanning calorimetry, and thermogravimetric analysis testing were performed for characterization and showed no effect of the nanofiller on the structural parameters of the composites, with the exception of a reduction in the crystallinity. Dynamic mechanical analysis revealed an increase in the glass‐transition temperature (T_g) at OMMT concentrations of 2 and 3.5 phr, whereas at 5 phr, T_g dropped again. Finally, mechanical testing showed an improvement in the tensile strength and stiffness, whereas improved solvent resistance was recorded by swelling experiments in toluene. This experimental study allowed us to explore the range where the OMMT filler produced NCs with silicone elastomers and, furthermore, showed that the incorporation of OMMT into silicone rubber did not introduce any chemical changes but increased the density of crosslinks; this led to a loss of crystallinity, an increase in T_g, and a significant improvement in the tensile properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Resistivity and thermal reproducibility of carbon black and metallic powder filled silicone rubber heaters

Flexible heaters were prepared by extruding platinum‐catalyzed silicone rubber composites with conductive carbon black (CB) and metallic fillers. The conductor resistivity of the extruded heaters decreased in order of conductive titanium dioxide (TiO₂) > aluminum powder ≈ zinc powder > copper powder. Thermoelectric switching phenomena were investigated for the silicone rubber/CB/metallic powder systems. The positive temperature coefficient effect was dependent mainly on the CB content rather than on the content of the metallic powders. Resistivity and thermal reproducibility of the extruded heaters were also investigated by periodically applying AC voltage of 110 V. The heaters containing copper and TiO₂ powders exhibited excellent electrical reproducibility. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1122–1128, 2005     

Enhancement in electrical and thermal performance of high-temperature vulcanized silicone rubber composites for outdoor insulating applications

High-temperature vulcanized silicone rubber composites are highly desirable as outdoor insulating materials due to their immense thermal and electrical performance. The aim of this work is to study the role of co-combined fillers (modified fumed silica [MFS], titanium dioxide [TiO₂], with graphene [G]) on electrical and thermal properties of silicone rubber (S) composites. The dielectric response of S/MFS_10 phr and S/TiO₂_20 composites tailored with 2 phr G was characterized by broadband dielectric spectroscopy. The hybrid filler/composites were found to show higher thermal stability when 2 phr G was added. In addition, a low quantity of G filler was found to slightly increase the AC dielectric breakdown strength of the S/MFS_10 and S/TiO₂_20, where an improvement of 3 and 5% was found, respectively. Several steps were observed in the thermal decomposition of the S rubber composites by thermogravimetric analysis-Fourier-transform infrared spectroscopy. Our findings revealed great potentials for fabricating hybrid-filler/silicone rubber composites with enhanced electrical and thermal properties for outdoor insulating applications.     

Effect of SiO2 and TiO2 nanoparticle on the properties of phenyl silicone rubber

Two types of nanoparticles TiO₂ and SiO₂ treated with silane coupling agents were incorporated into phenyl silicone rubber at a low concentration (≤1.0%) and cured by the room temperature vulcanized method. The results showed that treated TiO₂ or SiO₂ nanoparticles improved the ultraviolet (UV)‐shielding ability and enhanced the visible transmittance of the phenyl silicone rubber, compared with their respective untreated particles. Moreover, when comparing treated nanoparticles, TiO₂ was more responsible for augmenting the UV‐shielding ability of the phenyl silicone rubber, while SiO₂ played a more important role in increasing the transmittance of visible light. Low levels of nanoparticles reduced the dielectric constant of the nanocomposite; however, on reaching a critical concentration, increasing the nanoparticle content had the opposite effect. The thermal conductivity of nanocomposites increased linearly with the amount of treated nanoparticles, while SiO₂ nanocomposites exhibited better thermal conductivity than those of TiO₂. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42806.     

碳酸钙和氢氧化镁对加成型硅橡胶性能的影响

比较了碳酸钙和氢氧化镁对加成型硅橡胶力学、耐热、阻燃和防火性能的影响,分析了填料对硅橡胶热失重过程的影响。结果表明,碳酸钙可以提高硅橡胶的力学和防火性能;氢氧化镁可以提高硅橡胶的阻燃性能,但不能赋予硅橡胶防火性能;碳酸钙和氢氧化镁对硅橡胶防火阻燃性能的影响差异在于填料本身分解温度和硅橡胶燃烧分解温度的匹配性;两种填料并用可以赋予硅橡胶良好的防火、阻燃和耐热性能。