介孔分子筛的添加对PE基复合材料性能的影响

用熔融共混法制备出聚乙烯基纳米复合材料.研究了填充介孔分子筛MCM-41(带模板和无模板)颗粒以及不同的填充颗粒含量对复合材料拉伸性能的影响.结果表明,这种具有独特有机-无机复合结构的纳米介孔分子筛MCM-41(带模板)直接作填料,能与基体形成新型网络复合结构.因此,在MCM-41(带模板)的质量分数为2.5%时,复合材料的拉伸强度达到最大值,比基体树脂提高43.5%,弹性模量提高了50%;用MCM-41(无模板)作填料,在其质量分数为2.5%时,复合材料的拉伸强度达到最大值,比基体树脂提高52%,弹性模量提高了106%.     

Microwave preparation of a titanium-substituted mesoporous molecular sieve

A titanium-containing redox material with disordered wormhole-like mesoporous structure was prepared using microwave heating. Substantially accelerated crystallization was achieved using microwave heating compared with the conventional oven heating. Development of the mesopore structure was confirmed by XRD, TEM, and N₂ physisorption. Incorporation of titanium into the mesopore structure was confirmed by UV-vis spectroscopy. A laser light particle size analyzer showed that smaller particle size and narrower particle size distribution were obtained with microwave heating than with oven-heated hydrothermal synthesis. These mesoporous titanosilicates were equally active as catalysts for liquid-phase oxidation of 2,6-di-tert-butylphenol with hydrogen peroxide as an oxidant. This revised version was published online in July 2006 with corrections to the Cover Date.     

基于预沥青烯的有序结构中孔炭及其电化学性能

以预沥青烯为碳源、SBA-15为模板,采用模板法合成了结构有序的中孔炭材料。用XRD、TEM、N₂吸附和电化学工作站等对中孔炭的微观结构及电化学性能进行了研究。结果表明,以预沥青烯为碳源合成的炭材料具有高度有序的二维六方孔道和一定的石墨化程度,它反转复制了模板SBA-15的结构。中孔炭的比表面积为542 m²·g^-1,孔容为0.479 cm³·g^-1,孔径呈单峰分布,集中在3.5 nm左右。这种预沥青烯基中孔炭作为电化学电容器电极材料,显示出良好的性能,在1 mA的电流强度下其单电极质量比电容高达310 F·g^-1。     

Effect of preparation pH on properties of silica gel

Silica gels were obtained by drying the silica hydrogels formed at pH values between 1 and 4 at 100°C. The bulk density of the 2–3 mm diameter fraction decreased from 0·62 g cm^?3 to 0·20 g cm^?3 as the preparation pH increased from pH 3 to pH 3·65. The apparent density of silica gels was between 1·43 and 1·95 g cm^?3. Isotherms for the adsorption of water vapour on samples prepared at different pH values showed hysteresis in all cases. Thermogravimetry analysis showed that the amount of bound water was in the range of 4·4 to 5·5% on a dry weight basis. Specific heats were determined by a differential scanning calorimetry method using a sapphire standard and were between 0·82 and 0·97 J g^?1 K¹.     

Novel preparation and properties of EPDM/montmorillonite nanocomposites

This article reports on a novel route to develop ethylene–propylene–diene rubber (EPDM)/montmorillonite nanocomposites Modification of the MMT was carried out with maleic anhydride (MA), which acts as the intercalation agent for MMT and the vulcanizing agent for EPDM matrix, as well as the compatibilizer for the EPDM and MMT phases. The effect of MA‐modified MMT in nanocomposites was investigated by focusing on three major aspects: structural analysis, thermal properties, and material properties. The d‐spacings of both the MA modified MMT and exfoliated nanocomposites were investigated by X‐ray diffraction (XRD), and the morphology of these nanocomposites was examined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Dynamic mechanical analysis confirms the constraint effect of exfoliated MMT layers on EPDM chains, which benefited the increased storage modulus, increased glass transition temperature. Thermogravimetric analysis indicates that there is some enhancement in degradation behavior between the nanocomposites and EPDM matrix. The nanocomposites exhibit great improvement in tensile strength and modulus, as well as elongation‐at‐break. The effects of MA addition on the formation of nano‐metric reinforcement and on the mechanical properties of nanocomposites are discussed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 2578–2585, 2006     

苯并噁嗪/蒙脱土复合材料的制备及其性能研究

以有机MMT(蒙脱土)和苯并噁嗪(BZ)为主要原料,采用溶液插层法制备BZ/MMT复合材料。研究了有机MMT含量对BZ/MMT复合材料的热性能和力学性能等影响。结果表明:在其他条件保持不变的前提下,随着有机MMT含量的不断增加,复合材料的固化焓降低,热稳定性有所下降,拉伸强度呈先升后降态势;当w(有机MMT)=4%(相对于复合材料质量而言)时,复合材料的拉伸强度(1.6 MPa)相对最大,并且比纯BZ体系提高了20倍。     

中孔分子筛催化剂的研究进展

从4个方面回顾中孔分子筛催化剂的研究进展①代替传统酸催化剂催化大分子裂解,Friedel-Crafts的烷基化和酰基化反应;②向其骨架中引入Na+,Cs+等碱金属离子制得碱性催化剂催化Knoevenagel缩合反应;③引入Ti,Sn及Pt等过渡金属元素制得氧化还原催化剂以提高对大分子氧化反应的选择性;④负载其他活性物质.指出今后应在增加“中孔墙”的结晶度,增强酸性和增大孔径等方面做进一步的研究.     

Preparation and characterization of mesoporous silica-pillared montmorillonite

Mesoporous silica-pillared montmorillonites (SPMs) were prepared based on cation-exchange, gallery-templated synthesis method, and the post-synthesis treatment using ammonia, and characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), and N₂ adsorption–desorption. The results showed that ammonia played a very important role in the formation of the mesoporous materials; the calcined SPMs indicated a BET surface area of 511 m²/g and average pore size of 3.1 nm by adjusting the ammonia treating temperature at 110 °C. The formation of SPMs was discussed and its progressing mechanism was suggested.     

负载型中孔分子筛催化剂的研究进展

本文对M41S中孔分子筛作载体的负载试剂的研究进展进行了综述，主要介绍了负载酸型、负载碱型和负载氧化型催化剂的研究现状，以及对其应用和发展前景作了总结和评述。     

EP/有机化蒙脱土纳米复合材料的制备与性能研究

采用插层聚合法制备了环氧树脂/有机化蒙脱土(EP/OMMT)纳米复合材料。利用红外光谱(FT-IR)法和X射线衍射(XRD)法对OMMT结构进行了分析,并探讨了OMMT含量对不同纳米复合材料的结构、热性能和力学性能等影响。结果表明:经EP插层后,OMMT的层间距变大,并且发生了比较完全的剥离行为;OMMT的引入可有效提高不同纳米复合材料的热变形温度和玻璃化转变温度(前者提高了14～29℃,后者提高了2～27℃),并且其力学性能和耐湿热性能均优于纯EP体系。     

The preparation and properties of dextrin-graft-acrylic acid/montmorillonite superabsorbent nanocomposite

A novel superabsorbent nanocomposite was synthesized through intercalation polymerization of partially neutralized acrylic acid, gelatinized dextrin, and an organic-montmorillonite powder using N,N-methylenebisacrylamide as a crosslinker, Span-60 as a dispersant, and ammonium persulfate together with sodiumsulfite as a type of mixed redox initiator. Effects of the amount of them on water absorbency of the superabsorbent were investigated. The structure and the morphology of the nanocomposite were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and transmission electron microscopy analysis. The blood compatibility of the composite was primarily measured. The results show that the acrylic acid monomer was successfully intercalated into the organic-montmorillonite layers and bonded with them. The superabsorbent nanocomposite synthesized under optimal conditions with an organic-montmorillonite powder content of 5 wt% exhibit an absorption of 725.3 g/g in distilled water and favorable blood compatibility. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

WSiOx介孔分子筛的合成与表征

以阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)作为模板剂,正硅酸乙酯(TEOS)作为硅源,在强碱性条件下,加入过渡金属氧化物偏钨酸铵合成得到WSiOx介孔分子筛,使用乙酰丙酮作为助剂,考察其对孔结构的影响,通过X射线衍射仪(XRD)、N2吸附-脱附、原位红外(FT-IR)、扫描电镜(SEM)表征手段对合成出的WSiOx上分子筛的结构性能进行研究.随着W质量分数的增加,介孔特征衍射峰的有序度增加,质量分数大于6%后有序度下降;W的加入没有破坏介孔分子筛的骨架结构.最后的结果得到,最佳W质量分数为5%,模板剂质量分数为1.8%,乙酰丙酮质量分数为9%.平均孔径为4.68 nm,比表面积为966 m2/g.     

Synthesis and characterization of mesoporous molecular sieve nanoparticles

Mesoporous molecular sieve was prepared hydrothermally by a two-step method with materials of cetyltrimethyl ammonium bromide (CTAB), as a template, and sodium metaaluminate (NaAlO₂) and sodium silicate (Na₂SiO₃·9H₂O), as aluminum and silicon sources, respectively. The mesoporous molecular sieves are well ordered and have high thermal and hydrothermal stabilities. The as-prepared samples were characterized by powder X-ray diffraction (XRD), atomic force microscopy (AFM), transmission electron microscopy (TEM), thermogravimetry-differential scanning calorimetry (TG/DSC), Fourier transform infrared spectroscopy (FT-IR) and nitrogen adsorption experiments. Particle size distribution was in the 30–50 nm range, BET surface area was more than 800 m²/g, thermal stability was higher than 1023 K, the mesoporous structure was not entirely damaged at a calcination temperature of 1123 K and there was no clear change in ordering degree, pore size, and surface area of the mesoporous molecular sieve after hydrothermal treatment at 373 K for 10 days. The activity and selectivity of benzene hydrogenation to cyclohexane by mesoporous molecular sieve-supported Pt was up to 100%. The catalytic activity didn’t decline in a reaction period of 30 h.     

介孔二氧化硅-阿维菌素缓释体系的制备与性能研究

以正硅酸乙酯(TEOS)为硅源,氨水为碱性催化剂,采用无模板法制备介孔二氧化硅和中空介孔二氧化硅,选用持效期较短的阿维菌素作为模型药物构成缓释体系,通过扫描电镜(SEM)、透射电镜(TEM)、比表面仪(BET)、傅里叶红外光谱仪(FTIR)和紫外分光光度计(UV)对二氧化硅材料的形貌、粒径、载药量进行表征和测定,同时测试其缓释性能。探讨了溶剂蒸发法和超声浸渍法两种不同载药方法对缓释性能的影响。结果表明,两种农药缓释载体均呈球形,平均粒径500 nm,其中中空介孔二氧化硅载体具有独特的中空介孔复合结构,超声浸渍法载药效果较好,两种载体的载药量分别为48. 89%和52. 58%,中空介孔二氧化硅-阿维菌素缓释体系的缓释区间较大,缓释效果较好,31 h才基本达到平衡。     

低浓度氨氮废水处理技术研究进展

综述了低浓度氨氮废水目前主要的处理技术研究进展,主要介绍了化学法、生物法、高级氧化技术对低浓度氨氮的去除效果,并对该领域未来的发展方向做出了展望。指出,高级氧化技术作为目前水处理应用中一项新兴的技术,具有反应速度快,对可生化性差的废水污染物降解效率高等优点,已得到越来越多水处理工作者的关注,羟基自由基反应是高级氧化技术的根本特点,如何不断地提高羟基自由基生成率和利用率成为今后发展高级氧化技术的重要方向。     

MCM-48中孔分子筛的合成

在文献报道的水热法合成MCM 48中孔分子筛的基础上,针对在不同时期合成MCM 48合成重复性不好的问题,系统地考察了滴加正硅酸乙酯(TEOS)时溶液的温度,发现在溶液温度为20℃时滴加TEOS时配制的合成液能合成出有序性较高的MCM 48,并考察了焙烧温度及气氛对合成MCM 48中孔分子筛的影响,通过XRD、TG/DSC等对合成的产物进行了表征。     

微波合成Ti-MCM-41介孔分子筛及其动态脱硫性能

采用溶胶-凝胶法在微波条件下制备Ti-MCM-41介孔分子筛,采用SEM、BET、XRD、TEM和FT-IR等对催化剂进行表征,对比MCM-41和水热合成的Ti-MCM-41介孔分子筛,并分析其制备机理,以合成的分子筛为催化剂进行柴油脱硫实验。结果表明,合成的Ti-MCM-41分子筛结构有序,晶形完整,平均孔径约4.5 nm。在每10 mL模型油Ti-MCM-41用量0.2 g、n(H2O2)∶n(苯并噻吩)=4和V(乙腈)∶V(模型油)=1条件下,苯并噻吩的催化氧化活性较高,动态氧化-萃取脱除率最高达93.5%。     

水性聚氨酯/有机蒙脱土纳米复合材料的制备与性能研究

以IPDI(异佛尔酮二异氰酸酯)、PBA(聚己二酸丁二醇酯)、DMPA(二羟甲基丙酸)和OMMT(有机蒙脱土)为原料,制备了OMMT/WPU(有机蒙脱土改性水性聚氨酯)纳米复合材料。采用红外光谱(FT-IR)法、热失重分析(TGA)法等对该纳米复合材料的结构和性能进行了表征,并考察了OMMT含量对该纳米复合材料的热稳定性、疏水性和粘接性能等影响。研究结果表明:当w(OMMT)=3%(相对于WPU质量而言)时,纳米复合材料的综合性能相对最好,其热稳定性有所提高、疏水性和耐水解性(吸水率为17.67%)明显提高、初始剥离强度(1.8 N/mm)相对较大且最终剥离强度(3.5 N/mm)相对最大。     

介孔SAPO-11分子筛的制备及应用

综述了介孔SAPO-11分子筛的合成机理、制备方法及应用。介绍了介孔SAPO-11分子筛的合成机理,液晶模板机理和协同作用机理,在不同模板剂与无机硅源的静电作用或相互作用下形成液晶结构,移除液晶后,形成介孔孔道。SAPO-11分子筛属于微孔型(<2 nm)磷酸硅铝分子筛,通过模板法、后处理法和分子筛硅源法等制备方法得到的介孔SAPO-11分子筛结晶度良好,孔径和比表面积均增大,有利于大分子反应物进入其孔道和产物溢出。     

介孔SAPO-11分子筛的制备及应用

综述了介孔SAPO-11分子筛的合成机理、制备方法及应用。介绍了介孔SAPO-11分子筛的合成机理,液晶模板机理和协同作用机理,在不同模板剂与无机硅源的静电作用或相互作用下形成液晶结构,移除液晶后,形成介孔孔道。SAPO-11分子筛属于微孔型(<2 nm)磷酸硅铝分子筛,通过模板法、后处理法和分子筛硅源法等制备方法得到的介孔SAPO-11分子筛结晶度良好,孔径和比表面积均增大,有利于大分子反应物进入其孔道和产物溢出。