纳米氢氧化铝制备工艺条件与粒径的定量关系

采用均匀沉淀-共沸蒸馏法制备纳米氢氧化铝。为了得到制备条件与粒径的关系,考察了反应时间、搅拌速率、硝酸铝浓度、尿素与硝酸铝的物质的量比对粒径的影响。经验方程Y=9.58×10-4X21-0.996X1+76.54 lnX2+1.27X23-25.25X3+435.4X24-1 835.52X4+2 320.84可以很好地表示氢氧化铝的平均粒径与工艺参数的关系。在最佳条件下纳米氢氧化铝的平均粒径约为70 nm,绝大部分在100 nm以下。研究结果可用于纳米氢氧化铝粒径的控制和优化。     

Effects of carbon blacks on electrical properties of EPDM compounds

The correlations between mechanical and electrical properties of ethylene propylene diene terpolymer (EPDM) compounds and carbon black types and levels applied are studied. Tensile strength increases with an increase of the carbon black, especially for carbon black with higher surface area. Tracking resistance of EPDM compounds improves when a small amount of relatively nonconductive carbon blacks are added to EPDM compounds, whereas conductive carbon blacks decrease both dielectric properties and tracking resistance of EPDM compounds. Possible reasons for these results are discussed. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2540–2546, 2000     

氢氧化铝对脱醇型RTV-1硅橡胶性能的影响

以α,ω-二羟基聚二甲基硅氧烷为基胶、气相法白炭黑为填料、氢氧化铝为阻燃剂，制得无机阻燃脱醇型单组分室温硫化（RTV-1）硅橡胶。通过测试硅橡胶的阻燃性能、力学强度、锥形量热、热失重分析、交联密度和扫描电镜观察其拉伸断面形貌探讨了氢氧化铝对阻燃脱醇型硅橡胶的阻燃和力学性能的影响。结果表明，氢氧化铝不仅是脱醇型硅橡胶的良好阻燃剂，而且是其良好的补强剂；添加60份氢氧化铝时，脱醇型RTV1硅橡胶的燃烧氧指数达到36％，拉伸强度为1．34MPa，断裂伸长率为392％，邵尔A硬度为48度。     

Interfacial structure in vulcanized EPDM filled with mercaptosilane-treated Al(OH)3 and its influence on the mechanical properties

The reactivity of the alkoxy group in a silane coupling agent toward inorganic surfaces was investigated, and the structure of a silane-treated layer on the particle surface was analyzed. For this purpose, the various inorganic filler particles, SiO₂, Al(OH)₃, Mg(OH)₂, Al₂O₃, and CaCO₃ were treated with γ-mercaptopropyltrimethoxysilane. A strong interaction between the particle surface and the silane due to the hydrogen bonding and ionic interaction was confirmed except for CaCO₃ by electron spectroscopy for chemical analysis (ESCA). The structure of the silane layer on the particle surface was affected significantly by both the amount of added silane and the treatment conditions. Different silane structures, such as monolayer- or network-like, were formed on the particle surface. Their influences on the mechanical properties of filled vulcanized rubber were also investigated. The silane-treated filler particles, except CaCO₃, showed ability as a semi-reinforcing filler for vulcanized rubber. However, the structure of the silane-layer on the particle surface hardly affected the mechanical properties.     

铝酸钠溶液碳酸化分解过程中氢氧化铝粒度和强度的变化

模拟工业铝酸钠溶液连续碳酸化分解条件,对分解过程不同阶段产物氢氧化铝的粒度、磨损指数和结晶形貌的变化进行了研究。结果表明分解初期产物中粒径<45μm的粒子质量分数高达38%,分解中期产物粒度显著增加,而末期粒度的变化不再明显;分解1h时析出的大量细粒子的磨损指数最小,具有较高的抗磨损能力;中期经过快速附聚而变大的产物强度最差,附聚体经过后期析出氢氧化铝的"胶结"后强度又有所提高。SEM照片表明产物附聚体颗粒的缝隙内有细小颗粒填充,形成"镶嵌"式结构,且随着分解过程的进行附聚在一起的晶体颗粒粒度逐渐接近。     

氢氧化铝对有机硅电子灌封胶性能的影响

以端乙烯基硅油为基胶、含氢硅油为交联剂、γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH-570)为表面处理剂、Al(OH)3或Al(OH)3/铂络合物为阻燃剂,制备阻燃型有机硅电子灌封胶。研究结果表明:对Al(OH)3表面进行处理、降低其粒径、增加其含量、Al(OH)3/铂络合物并用等均有利于提升灌封胶的阻燃性能;当w(KH-570)=0.5%[相对于Al(OH)3质量而言]、Al(OH)3的平均粒径为2.6μm、m(5.0μmAl2O3):m[2.6μm Al(OH)3]=160:40和w(铂络合物)=0.002%(相对于基胶质量而言)时,可制得阻燃性优异的有机硅电子灌封胶。     

环氧/氢氧化铝复合材料性能研究

采用水解的KH-560处理微米级Al(OH)3粉末,改善其与树脂基体的表面相容性。通过FTIR对处理后的Al(OH)3进行了表征。优化了偶联剂水解条件及用量,并对不同Al(OH)3填充量的环氧/氢氧化铝复合材料分别采用热常数分析仪及电子万能试验机测试了其热导率和力学性能。结果表明,最佳水解条件为8%的KH-560在pH=4.5溶液中室温水解40 min。当KH-560的质量分数为Al(OH)3的10%左右时,效果最优。材料的热导率随着Al(OH)3填充量的增加而增高。填充量为6%时,力学性能达到最优。     

Al(OH)3对硅橡胶性能的影响

综述了Al（OH)3粒径和用量对硅椽胶漏电电流、脉冲电流、耐漏电起痕、表面粗糙程度、电蚀损、介电性能、拉伸强度及漏电电流实验重复性的影响。     

Effects of the Treatment of Al(OH)3 by a Silane Coupling Agent on the Tensile Properties of PVC/Al(OH)3 Composite

The present work deals with the study of a composite based on poly(vinyl chloride) (PVC) and aluminum hydroxide (Al(OH)₃) which is treated with different concentrations of the silane coupling agent N-(2-aminoethyl)-3-aminopropyltrimethoxysilane.

The composites containing untreated Al(OH)₃ and those treated with the coupling agent were prepared by melt mixing using a two-roll mill.

Analysis of the treated filler by means of Fourier Transform Infrared spectroscopy (FTIR) showed the formation of oligoaminosilanes resulting from the condensation of the silane coupling agent.

The tensile properties of the PVC/Al(OH)₃ composite reflected the effect of the addition of the mineral filler and also the influence of the chemical treatment on the interfacial adhesion. The incorporation of aluminum hydroxide into PVC resulted in an increase of Young's modulus and the yield stress.

From the calculation of a parameter B which was used to quantify the state of adhesion between the polymeric matrix and the filler, it was concluded that the surface chemical treatment of the filler with the silane coupling agent leads to higher reinforcement as a result of the interfacial interactions developed between PVC and Al(OH)_3.     

超细Al(OH)3对PP球晶结构和性能的影响

分别用超细Al(OH)_3和普通Al(OH)_3填充聚丙烯(PP),研究了超细Al(OH)_3/PP和普通Al(OH)_3/PP体系的力学性能、熔体流动性、阻燃性能及其结晶的微观形态。结果表明,加入适量的超细Al(OH)_3对PP具有增韧效应;超细Al(OH)_3能使PP球晶显著细化;与普通Al(OH)3/PP相比,超细Al(OH)_3/PP具有较好的抗冲击性能、拉伸性能和弯曲性能,但熔体流动性低。     

PP/Al(OH)_3/Mg(OH)_2/ZB阻燃复合材料的拉伸性能

制备了氢氧化铝、氢氧化镁、硼酸锌和纳米碳酸钙填充聚丙烯3种阻燃复合材料,应用CMT4104型万能试验机在室温下测试其拉伸性能。结果表明,复合材料的扯断应变随着阻燃剂质量分数的增加而下降,拉伸强度近似呈线性减小,弹性模量则呈非线性提高。     

Effect of particle size on the properties of Mg(OH)2‐filled rubber composites

A novel nanomagnesium hydroxide powder and three kinds of micro‐Mg(OH)₂, with different particle sizes, were chosen as fillers and mixed with ethylene–propylene–diene monomer rubber (EPDM) to form a series of composites by a traditional rubber‐processing technique. The results showed that the mechanical properties of composites improved with decreasing particle size. The nanocomposites were far stronger than the microcomposites, which also supported the view that rubber reinforcement requires nanoreinforcement. The effect of particle size on the fire resistance of composites was investigated by cone calorimetry and limiting oxygen index analysis, which showed that the particle size of powder had an impact on the fire resistance of composites. For the composites filled with untreated powder, the peak value of heat release rate decreased and T_ign increased with decreasing particle size. In conclusion, the fire resistance of nanocomposites was better than that of microcomposites. Surface modification of particles sometimes substantially improved the mechanical properties of nanocomposites, but had no effect on either the mechanical properties of microcomposites or the fire resistance of nanocomposites and flame retardance. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2341–2346, 2004     

Detrital Mg(OH)2 and Al(OH)3 in Microwaved Hydrotalcites

Microwave irradiation power (90, 180, 270 or 360 W) determines the composition and the structure of the compounds obtained when pH is increased, decreased or maintained constant during preparation. Although in all cases the X-ray diffraction patterns show that the obtained compounds are hydrotalcite-like, the surface areas (40 up to 240 m²/g) as well as other microcrystalline compounds have to be inferred, such as Al(OH)₃ or Mg(OH)₂.     

Al2O3的粒子尺寸对天然橡胶导热性能的影响

以天然橡胶为基体,微米Al2O3和纳米Al2O3为导热填料,比较了纳米Al2O3和微米Al2O3填充的导热橡胶的导热性能和物理机械性能,并将2种粒子以不同配比加入天然橡胶基体中,对其影响进行了探讨.结果表明,随着微米Al2O3填充份数的增加,天然橡胶的热导率增大,物理机械性能先升高后下降;在相同填充量下,微米Al2O3填充的导热橡胶比纳米Al2O3填充的导热橡胶具有更好的导热性能和物理机械性能;在合适的配比下,纳米Al2O3与微米Al2O3混合填充的导热橡胶的导热效果优于单一使用Al2O3粒子的填充效果.     

甲基丙烯酸对氢氧化铝填充丁苯橡胶性能的影响

将甲基丙烯酸（MAA）用作Al(OH）3填充丁苯橡胶（SBR）复合材料的添加剂，结果表明，在高填充Al(OH）3的SBR中加入MAA可以较大幅度地提高其过氧化物硫化胶的力学性能。当Al(OH）3用量为150份（质量份，下同）时，随着MAA用量增加，SBR硫化胶的邵尔A型硬度和定伸应力逐渐增大，拉伸强度和撕裂强度有较大幅度的提高，当MAA用量为20份时，随着Al(OH）3用量增加，SBR硫化胶的邵尔A型硬度、定伸应力和撕裂强度逐渐增大，拉伸强度在Al(OH）3填充量为25份时最大，大量填充Al(OH）3的SBR硫化胶的阻燃性能较好，氧指数受MAA用量的影响较小，该SBR硫化胶亦具有良好的热空气老化性能。     

Flammability and mechanical properties of Al(OH)3 and BaSO4 filled polypropylene

The flammability and mechanical properties of Al(OH)₃/BaSO₄/polypropylene (PP) composites were investigated. The flow, morphological, and thermal properties were also analyzed by melt flow index (MFI), Scanning electron microscopy (SEM), and Differential scanning calorimeter (DSC) studies, respectively. Total filler amount was fixed at 30 wt % to optimize physical characteristics of the composites. In addition to the flame retardant filler Al(OH)₃, BaSO₄ was used to balance the reduction in impact strength at high filler loadings. Substantial improvement in mechanical properties was achieved for 20 wt % Al(OH)₃ (i.e., 10 wt % BaSO₄) composition while maximum flammability resistance was obtained for 30 wt % Al(OH)₃ composite. SEM studies showed that the presence of aggregated Al(OH)₃ particles led to low interfacial adhesion between them and PP matrix ending up with decreased mechanical strength. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

ZnO/MoO3/Al(OH)3阻燃聚丙烯材料的制备及性能

采用水热法制备了一维材料ZnO和MoO_3纳米线(nanowires,NWs),并通过SEM和XRD对纳米线的形貌和结构进行了表征。将一维纳米线和纳米氢氧化铝(ATH)与聚丙烯(PP)熔融共混制备了ZnO/MoO_3/Al(OH)_3/PP复合材料(NWs/ATH/PP)。利用TGA、极限氧指数(LOI)测定仪和锥形量热仪(CCT)表征了复合材料的热稳定性和燃烧性能,利用万能材料试验机测试了复合材料的力学性能。结果表明:当添加质量分数3.75%ZnO纳米线、质量分数3.25%MoO_3纳米线和质量分数21.00%纳米ATH时,NWs/ATH/PP复合材料的初始分解温度较纯PP增加了17.8℃,残重率为24.6%,峰值热释放速率(PHRR)和总热释放量(THR)分别下降了54.3%和25.7%,LOI提高7.1%。SEM结果显示:NWs/ATH/PP的残炭表面致密、连续且平整。     

改性纳米Al(OH)3粉体的制备

以铝酸钠溶液和二氧化碳气体为原料，采用碳分法制备纳米Al(OH)3粉体. 考察了原料液浓度、气液流量比、旋转填料床转速等因素对Al(OH)3粒径d50的影响. 在Al(OH)3胶体溶液中添加复合表面活性剂三乙基苄基氯化铵/磷酸钠(TEBAC/PO43-)，对Al(OH)3粒子进行防团聚研究. 利用XRD和TEM等测试方法对最终产物进行了分析表征，表明所制备的Al(OH)3粒子呈单斜晶系，具有憎水性，粒度分布均匀，平均粒径20 nm.     

氢氧化铝在丁苯橡胶中的阻燃性研究

研究了不同品种无机阻燃剂在丁苯橡胶中的氧指数(OD值及其有关性能。结果表明，单用A1(OH)3时OI值比较高，燃烧时没有可见的烟雾，随Al(OH)3用量提高OI值上升，当用量达12O份时，OI值达27。以Al5l改性Al(OH)3 ，未能提高OI值，物理机械性能稍有改善。Al(OH)3粒径微细化能有效提高OI及物理机械性能。     

Effect of polytetrafiuoroethylene on flame retardancy and mechanical properties of silicone rubber filled with Mg ( OH ) 2/Al ( OH ) 3 complex

研究了聚四氟乙烯(PTFE)对Mg(OH)2/Al(OH)3填充硅橡胶阻燃性能和力学性能的影响.结果表明,PTFE不但能够改善硅橡胶的阻燃性能,而且还能使力学性能尤其是撕裂强度得到显著提高.当PTFE用量为2.5份(质量),撕裂强度达17.1 kN·m-1,比不含PTFE的试样提高了51%,而且其极限氧指数也有一定增加.