表面改性锌镁铝三元类水滑石的摩擦性能及抗磨机理(英文)

经共沉淀法和水热法合成了锌镁铝三元类水滑石(Zn/Mg/Al-LDHs)纳米粉体,并用油酸进行表面改性。采用X射线衍射,扫描电子显微镜(SEM),红外光谱和X射线荧光光谱等测试对Zn/Mg/Al-LDHs纳米粉体进行了表征。采用四球摩擦试验机,SEM和X射线光电子能谱(XPS)等手段对类水滑石的摩擦性能以及磨损钢球表面进行了分析。结果表明:类水滑石具有典型的六方片层结构,晶粒尺寸均匀,平均粒径为179.4nm;化学式为Zn0.37Mg0.27Al0.36(OH)2(CO3)0.18·0.31H2O;改性后,油酸在类水滑石表面呈单分子层吸附;类水滑石在高载荷(200~400N)和适当的转速下可显著降低金属摩擦副的摩擦系数和磨斑直径。XPS结果显示,磨损表面生成了含有ZnO,ZnS,MgO,氧化铁等化合物和有机物的化学反应保护膜,同时,纳米颗粒抛光和第三体效应也起到了减磨抗磨作用。     

铜镁铝类水滑石插层改性及摩擦性能研究

采用液相共沉淀法制备了铜镁铝类水滑石,选用十二烷酸（月桂酸）作为改性剂以离子交换法对类水滑石进行插层改性。借助红外光谱仪对改性前后类水滑石进行成分、结构、形貌分析与表征。实验结果表明,制得的类水滑石为Cu-Mg-Al-CO3、改性类水滑石为Cu-Mg-Al-月桂酸。将改性前后类水滑石以3%（质量分数）的比例添加到摩擦材料的基础配方中制成摩擦片,利用XD-MSM定速式摩擦试验机测试添加改性前后类水滑石制得摩擦材料的摩擦系数随温度的变化规律,用静水力学密度仪测试摩擦片的密度。结果表明,将未改性类水滑石加入摩擦材料中可以降低摩擦材料的摩擦系数,而加入改性类水滑石,因粒径膨胀,使得摩擦材料的摩擦系数有所增大;改性的类水滑石可以降低摩擦片的密度。     

Mg-Al类水滑石的制备及摩擦性能

采用水热法制备了Mg-Al-NO3和Mg-Al-SDSO类水滑石。讨论了pH值、十二烷基磺酸钠(SDSO)浓度[c(SDSO)]对Mg-Al-SDSO类水滑石结晶度的影响,利用X射线衍射法、红外光谱分析法、热重–差热分析法对样品的成分、结构及热稳定性进行了表征,结果表明:当pH=11,c(SDSO)=0.1mol/L时可以合成结晶度高的Mg-Al-SDSO类水滑石。比较了Mg-Al-NO3和Mg-Al-SDSO类水滑石的减磨效果,将制备的样品加入到基础油中,用四球摩擦磨损试验机测试了其摩擦学性能,结果表明:含有Mg-Al-NO3和Mg-Al-SDSO类水滑石粉体的润滑油与基础油相比,摩擦因数分别降低了24.2%和28.3%。     

镁铝水滑石去除氯离子性能研究

利用水滑石(LDH)焙烧后在一定条件下可重新吸收水和阴离子,从而部分恢复层状结构的结构记忆效应,研究了焙烧镁铝碳酸根水滑石(CLDH)在处理含氯废水中的应用.实验表明,当CLDH镁铝比为4:1、焙烧温度为500℃、水滑石质量浓度为2.0 g/L、处理温度为30℃时,CLDH对氯离子的处理效果最佳.     

Cu-Mg-Al类水滑石的插层改性及摩擦性能

用水热法制备了Cu-Mg-Al类水滑石,并以十二烷基磺酸钠（sodium dodecyl sulfate,SDSO）为插层剂对所制备的类水滑石样品进行了插层改性。利用X射线衍射法、红外光谱分析法、扫描电子显微镜和热重-差热分析法对样品的成分、结构、形貌及热稳定性进行了表征,结果表明：制备出的类水滑石为Cu-Mg-Al-CO3类水滑石和Cu-Mg-Al-SDSO类水滑石。将制备出的类水滑石作为添加剂加入到基础油中,用MM-10W多功能型四球摩擦磨损试验机测试了其摩擦学性能,结果表明：含有类水滑石粉体的润滑油与基础油相比,摩擦因数低了32%。     

纳米铜-镁-铝类水滑石的制备与表征

采用恒定pH低过饱和共沉淀法制备纳米铜-镁-铝类水滑石,采用单因素试验得出最佳反应工艺条件。在超声波反应器中反应,恒定pH=7.5~9.0,n(铜+镁)/n(铝)=2.0~4.0,n(铜)/n(镁)=0.25~1.0的条件下,采用冷冻干燥法可得到晶相单一的铜-镁-铝类水滑石,且制得的产物晶面生长的有序程度高,结晶度好。采用X射线衍射(XRD)、红外光谱(FT-IR)和扫描电镜(SEM)对其进行表征,大多数分子粒度为纳米级尺寸,粒径为50 nm左右。     

镁铝铁三元类水滑石对印染废水的吸附性能研究

采用共沉淀法合成出一系列镁铝铁不同摩尔比的磷酸二氢根型三元类水滑石（HTLCs）;考察了该类水滑石及其焙烧产物（cHTL）对直接大红染料废水的吸附性能。实验结果表明,以镁铝铁摩尔比为3：0．25：0．75制得的HTLCs对直接大红的脱色效果最好;HTLCs和cHTL对直接大红染料的吸附规律均更好地符合准二级动力学方程和Langmuir等温式,但cHTL的吸附量明显高于HTLCs;两者的饱和吸附量分别为112．65mg·g^-1和359．05mg·g^-1;经5次重复利用的HTLCs和cHTL对直接大红的脱色。率仍高达80%以上。     

锌镁铝类水滑石的制备与表征研究

以锌、镁、铝的水合硝酸盐及尿素等为主要原料,通过水热合成法制备具有层状结构的锌镁铝类水滑石(ZnMgAl-HTLCs).采用XRD、SEM、FT-IR及MP-AES等对样品的晶体结构、微观形貌、元素组成及材料表面性质等进行了表征分析.考察了锌的掺杂量、尿素浓度、二价三价金属离子比和溶剂等因素对水滑石结构及形貌的影响.结果表明,M2 +/M3为4.5∶1 ～6∶1,锌的掺入比例在10％～30％之间,尿素的浓度为0.54 ～0.61 mol/L,时间为24h,可以得到结构单一和形貌较好的锌镁铝类水滑石.     

反应时间对镁铝水滑石制备及其性能的影响

采用X射线衍射（XRD）和红外光谱（IR）测定液相沉淀工艺制备镁铝水滑石试样的相组成及其结晶状况,利用差热（DTA）-热重（TG）分析测定试样的热性能。研究发现：反应时间对水滑石晶体晶相组成及热分解性能的影响。     

镍镁铝三元水滑石类化合物的合成和表征

采用恒定pH值法合成了NiMgAl-HTLcs三元类水滑石化合物,利用X射线衍射、差热分析对合成物进行了表征.讨论了pH值、原料配比、焙烧温度对合成水滑石结构的影响.结果表明在体系pH值8～9,n(Mg+Ni)n(Al)=1～3、n(Mg)n(Ni)=8～16条件下采用恒定pH值法可得到晶相单一的NiMgAl-HTLcs,焙烧温度高于500℃水滑石结构完全破坏,生成NiO、MgO和Al2O3复合氧化物.     

催化领域中水滑石类层柱材料的技术现状及国内专利分析

文章简述了水滑石类层柱材料在催化领域的应用,从专利申请量年度分布情况、申请人类型统计和申请人排名情况三个方面进行统计分析,通过对数据的比较和分析,得出了我国水滑石类层柱材料在催化领域的研究现状、应用水平和研究趋势。     

Enhanced Ionic Conductivity in Poly(ethylene oxide)/Layered Double Hydroxide Nanocomposite Electrolytes

All solid-state poly(ethylene oxide) (PEO) nanocomposite electrolytes were made containing nanoscale fillers of layered double hydroxides (LDHs). Two kinds of oligo(ethylene oxide) modified LDHs were prepared by template method, and added into PEO/LiClO₄ matrix (with EO/Li molar ratio of 8) to study the effect on the ionic conductivity of PEO/LDH nanocomposite electrolytes. The structures of the modified LDHs were characterized by infrared spectra, thermogravimetric analysis and wide-angle X-ray diffraction. The results show that the oligo(ethylene oxide) with phosphonate anion can be effectively intercalated into the gallery region of LDHs and formed as an organic-inorganic hybrid (PLDH). With enhanced compatibility of LDH sheets by oligo(ethylene oxide) surface modification, the PEO/PLDH nanocomposite exhibits fully exfoliation morphology. The well dispersed LDH layers in PEO/LiClO₄/PLDH nanocomposite electrolytes rendering the formation of amorphous phase, results in an enhancement of ionic conductivity by three orders of magnitude compared to the pure PEO/LiClO₄ polymer electrolyte. This novel nanocomposite electrolytes system with high ionic conductivity will be benefited to fabricate the thin-film type of Li-polymer secondary battery. This revised version was published online in July 2006 with corrections to the Cover Date.     

水滑石在阻燃聚丙烯腈纤维改性中的应用研究

在经十二烷基硫酸钠柱撑的水滑石层间进行丙烯腈的原位聚合反应，用红外光谱和X-射线衍射对聚合物样品进行了结构分析与表征，并对聚丙烯腈／柱撑水滑石共混物样品的燃烧性能进行了研究。结果表明：丙烯腈单体在水滑石片层之间发生原位聚合反应，生成聚丙烯腈大分子，并使水滑石片层间距有一定程度的增大；共混物的极限氧指数从18．1％提高到了25．5％，同时共混物的热重曲线向高温方向发生了偏移，阻燃性能得到一定程度改善。     

New Nanocomposites Based on Syndiotactic Polystyrene and Organo-Modified ZnAl Layered Double Hydroxide

New nanocomposites were prepared by mixing syndiotactic polystyrene (sPS) with organo-modified ZnAl layered double hydroxide (O-ZnAl-LDH) in toluene solution. Both wide-angle X-ray diffraction (WXRD) and transmission electron microscopy (TEM) examinations confirmed the nanocomposite formation with exfoliated or intercalated O-ZnAl-LDH distributed in the sPS matrix. Meanwhile, the nonisothermal crystallization behavior of the resulting nanocomposites was studied using differential scanning calorimetry (DSC) technique at various cooling rates. The results indicated that the O-ZnAl-LDH particles in nanometer size might act as nucleating agents and accelerate the overall nonisothermal crystallization process.     

Precursor Preparation to Promote the Adsorption of Mg‐Al Layered Double Hydroxide

This study presents an interesting phenomenon of the simultaneous occurrence of adsorption and synthesis of Mg–Al layered double hydroxide (Mg–Al–LDH) by stirring a precursor in an aqueous solution with methyl orange (MO) as target adsorbate with the precursor prepared by first milling Mg(OH)₂ for 1 h followed by another 3 h milling with Al(OH)₃.The prepared precursor and LDH samples were characterized by a set of analytical methods including X‐ray diffraction (XRD), thermogravimetry/differential scanning calorimetry (TG–DSC), and Fourier‐transform infrared (FT–IR). The maximum adsorption capacity (Q_m) of MO by the prepared precursor sample was 1110.2 mg/g, much higher than that from the synthesized LDH sample. Engineering application may be expected from the easy preparation of such precursor as adsorbent to purify the tremendous amounts of dye wastewater.     

丙烯酸改性水滑石接枝PP的制备工艺

采用单一变量法研究了化学参数(接枝单体用量、引发剂用量)和加工参数(螺杆转速、螺杆温度)对丙烯酸改性水滑石(AA-LDH)和聚丙烯(PP)接枝反应的影响。结果表明,通过FTIR谱图证实了丙烯酸接枝到PP上。随着AA-LDH含量的增加,接枝物的接枝率呈现先增大后减小的趋势,在AA-LDH用量为5.0 g时,接枝率有最大值,为1.45%;接枝物的拉伸强度和弯曲强度随着AA-LDH用量的增加逐渐减小,而冲击强度却随着AA-LDH用量的增加而逐渐增大。改变引发剂过氧化二异丙苯(DCP)用量、螺杆温度和螺杆转速,接枝物的力学性能的变化规律和接枝率的变化规律相似,都是呈现先增大后减小的趋势。综合分析得到制备AA-LDH接枝PP的最佳工艺条件为:PP用量为100 g时,AA-LDH用量为5.0 g,DCP用量为0.2 g,螺杆温度为190℃,螺杆转速为300 r/min。     

二氟尼柳嵌入镁铝水滑石的合成表征与研究

采用共沉淀法、离子交换法和焙烧复原法三种不同方法将二氟尼柳嵌入Mg-Al水滑石层间,得到一种有机-无机复合层状材料.通过XRD、IR、TG-DTA和元素分析等手段对材料表征,结果表明,共沉淀法和离子交换法成功地将二氟尼柳嵌入水滑石,得到的材料层状结构完整、晶相单一,且层间距扩大为1.81～2.14 nm;IR分析表明二氟尼柳嵌入水滑石后,原二氟尼柳分子中的νC=O振动峰消失,在1567 cm(1和1412 cm(1处出现羧酸盐的-COO(对称与不对称吸收谱带;二氟尼柳嵌入水滑石后其分解温度提高了140～180℃.此外,根据表征结果建立了材料超分子结构模型, 即客体二氟尼柳与水滑石层板之间以静电力和氢键相互作用,以双层交替式倾斜地排列于层板之间.     

Delamination of Mg-Al Layered Double Hydroxide on Starch: Change in Structural and Thermal Properties

Mg-Al layered double hydroxide decorated starch bionanocomposites (starch/layered double hydroxide) are prepared by solution intercalation method. The bionanocomposites are systematically characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and high-resolution transmission electron microscopy techniques. The thermal stability of starch is enhanced due to dispersion of layered double hydroxide within the starch matrix. The chemical resistance property of starch is improved substantially with slight sacrifice in biodegradation behavior by the delamination of layered double hydroxide in starch matrix. Herein, layered double hydroxide acts as potential laminated filler for change in structural, thermal, and chemical resistance properties of starch with little sacrifice in biodegradable behavior.     

Preparation and Properties of ZnAl Layered Double Hydroxide/Polycaprolactone Nanocomposites for Use in Drug Delivery

ZnAl-layered double hydroxides (ZnAl-LDH)/polycaprolactone (PCL) nanocomposites were prepared by solution intercalation method. It is shown that lamellar ZnAl-LDH is randomly distributed in the PCL matrix with diameter of 60 nm. The addition of ZnAl-LDH decreases thermal decomposition temperature of composites, but improves the elastic modulus and tensile strength. The weight loss and release amount of diclofenac of ZnAl-LDH/PCL composites are higher than that of neat PCL. The drug release kinetics for nanocomposites and neat PCL could be described by first-order kinetic and Ritger-Peppas kinetic model.