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单分散短棒状介孔二氧化硅的制备 总被引:2,自引:0,他引:2
在温和碱性条件下,以十六烷基三甲基溴化铵为模板剂,正硅酸乙酯为硅源,平平加Os-25为助剂,制备出轴向尺寸为200nm左右,径向尺寸在60-80nm范围内的单分散短棒状纳米介孔二氧化硅MCM-41.研究了CTAB用量、平平加Os-25的用量、反应时间等因素对介孔形貌和纳米粒子分散性的影响.结果表明,适量的非离子表面活性剂平平加Os-25具有助模板剂的作用,可以有效地提高纳米介孔粉体的有序性.平平加Os-25与十六烷基三甲基溴化铵的摩尔比在0.02-0.06范围内,可以得到有序性好、分散性好的短棒状介孔二氧化硅MCM-41. 相似文献
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张开业王健费国霞夏和生 《高分子材料科学与工程》2018,(8):117-123
胶乳法是制备石墨烯及其衍生物橡胶纳米复合材料最常用的方法,文中在胶乳法的基础上,将静电自主装的技术运用于石墨烯基/橡胶纳米复合材料领域,即,将正电荷的十六烷基三甲基溴化铵修饰的介孔二氧化硅纳米粒子(MCMNH4H)、表面带负电荷的氧化石墨烯、表面带负电荷的橡胶乳胶粒共混,使三者在水溶液中发生静电自组装制备了一种新型三元复合纳米材料。通过红外光谱、X射线衍射、扫描电镜等测试手段对制备的材料进行了结构表征,系统地研究了氧化石墨烯(GO)和MCM-NH4H对复合材料性能的影响。结果表明,MCM-NH4F和GO之间的协同作用极大地提高了复合材料的性能,当GO的用量为0.75phr时,复合材料的拉伸强度达到29.4 MPa,提高了32.6%,介电性能具有一定程度的提升。 相似文献
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以2-氰乙基三乙氧基硅烷(CTES)和正硅酸乙酯(TEOS)为硅源,聚氧乙烯聚氧丙烯聚氧乙烯三嵌段共聚物(P123)为模板剂,采用共缩聚法在酸性条件下合成了氰基功能化的介孔二氧化硅.通过XRD、SEM、氮气吸附脱附、FT-IR和元素分析等技术对样品的结构、形貌、孔性质和官能团等进行了表征.研究结果表明,硅源的混合方式对氰基的引入量和分布有一定影响,其中以直接混合方式所得样品中基团含量最高,其分布也最均匀.另外,随着氰基引入量的增加,样品的形貌与孔结构略有变化.当CTES加入量超过20mol%时,材料的介孔由圆柱形的直孔道向瓶颈型的孔道结构发生转变.同时随着材料中氰基含量增大,样品的孔容由0.70 cm3/g降到0.22 cm3/g、表面积从666 m2/g降到312 m2/g,孔径由4.2 nm减小到2.7 nm,表明氰基分子占据了部分孔道空间. 相似文献
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以尿素-过氧化氢为混合模板、正硅酸乙酯为硅源,在酸性条件下,通过溶胶-凝胶过程合成二氧化硅介孔材料。采用煅烧法除去模板剂,用红外光谱、XRD、N2吸附-脱附、HRTEM等分析测试手段对介孔材料的结构和形态进行了表征。结果表明:与以尿素为单一模板相比,采用混合模板剂所合成介孔材料为蠕虫状,孔径分布基本保持不变、比表面积相近(分别为445、431m2/g)、孔径(分别为7.04、8.11nm)和孔体积(分别为0.783、0.874cm3/g)明显增大。 相似文献
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高朋余传柏杜琳琳高满罗海强梁智杰韦春 《高分子材料科学与工程》2018,(11):125-129
以静止法合成了结构有序的单分散介孔SBA-15(MSBA-15),并对其进行偶联处理,再通过与环氧树脂熔融共混、浇注成型和后固化等工艺,制得了单分散介孔SBA-15/环氧树脂复合材料(MSBA-15/EP)。利用红外光谱、X射线衍射、扫描电镜和N2吸附等手段对MSBA-15偶联处理前后进行表征,并测试了复合材料的力学性能与动态力学性能。研究结果表明,合成的MSBA-15具有较好的单分散性和介孔结构特征,偶联处理对其介孔结构和有序性影响较小。经偶联处理的MSBA-15在环氧树脂基体中有较好的分散性,与纯环氧树脂相比较,当MSBA-15质量分数为5%时,MSBA-15/EP复合材料的拉伸强度提高了28%,玻璃化转变温度(Tg)提高了7℃,同时初始储能模量提高9.4%,复合材料断面形貌分析表明,两相的界面相容性较好,断面表现为韧性断裂。 相似文献
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以一种松香基双季铵盐和CTAB为共混模板,正硅酸乙酯为硅源,通过调节两种表面活性剂的不同用量,在碱性条件下水解制备了SiA、SiB、SiC、SiD4种SiO2材料。采用TGA确定煅烧温度为550℃;SEM照片分析可知SiC、SiD的微观形貌优于SiA、SiB,且为分散均匀的球形颗粒,无团聚;TEM照片分析可知,SiC、SiD为具有介孔结构的球形颗粒;FT-IR确证了SiC、SiD煅烧前后的基本结构;经氮气吸附-脱附实验分析,结果表明,SiC、SiD的孔径主要集中在3.8nm处,比表面积和累积孔体积分别为685.29m2/g、1.22cm3/g和609.73m2/g、0.93cm3/g。 相似文献
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首先合成了一种新型双功能性离子液体1-甲基-3-(3'-磺酸丙基)咪唑十二烷基磺酸盐([PMIM(SO3H)][C12SO3]),并采用FT-IR、1H NMR和13C NMR对其结构进行了表征;进一步以该离子液体为模板剂和酸源,以正硅酸乙酯(TEOS)为硅源,通过溶胶-凝胶法制备出介孔SiO2,利用TGA和FT-IR研究了介孔材料的形成过程,采用SAXRD、SEM、TEM和氮气等温吸附-脱附等手段对介孔材料的结构形貌进行了表征,并研究了其对Pb2+的吸附性能。结果显示,以[PMIM(SO3H)][C12SO3]为模板剂和酸源制备的介孔SiO2其比表面积、孔容、平均孔径大小分别为1 010m2/g、0.95 cm3/g、3.25 nm,其对重金属Pb2+有很好的吸附性能。 相似文献
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Lee J Kim J Kim J Jia H Kim MI Kwak JH Jin S Dohnalkova A Park HG Chang HN Wang P Grate JW Hyeon T 《Small (Weinheim an der Bergstrasse, Germany)》2005,1(7):744-753
Hierarchically ordered mesocellular mesoporous silica materials (HMMS) were synthesized using a single structure-directing agent. The mesocellular pores are synthesized without adding any pore expander; the pore walls are composed of SBA-15 type mesopores. Small-angle X-ray scattering revealed the presence of uniform pore structures with two different sizes. Using HMMS as a nanoscopic template, hierarchically ordered mesocellular mesoporous carbon (HMMC) and polymer (HMMP) materials were synthesized. HMMS was used as a host for enzyme immobilization. To improve the retention of enzymes in HMMS, we adsorbed enzymes, and then employed crosslinking using glutaraldehyde (GA). The resulting crosslinked enzyme aggregates (CLEAs) show an impressive stability with extremely high enzyme loadings. For example, 0.5 g alpha-chymotrypsin (CT) could be loaded in 1 g of silica with no activity decrease observed with rigorous shaking over one month. In contrast, adsorbed CT without GA treatment resulted in a lower loading, which further decreased due to continuous leaching of adsorbed CT under shaking. The activity of crosslinked CT aggregates in HMMS was approximately 10 times higher than that of the adsorbed CT, which represents a 74-fold increase in activity per unit weight of HMMS due to higher CT loading. 相似文献
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Aqueous heavy metals removal by adsorption on amine-functionalized mesoporous silica 总被引:3,自引:0,他引:3
Aguado J Arsuaga JM Arencibia A Lindo M Gascón V 《Journal of hazardous materials》2009,163(1):213-221
Amino functional mesoporous silica SBA-15 materials have been prepared to develop efficient adsorbents of heavy metals in wastewater. Functionalization with amino groups has been carried out by using two independent methods, grafting and co-condensation. Three organic moieties have been selected to incorporate the active amino sites: aminopropyl (H(2)N-(CH(2))(3)-), [2-aminoethylamino]-propyl (H(2)N-(CH(2))(2)-NH-(CH(2))(3)-) and [(2-aminoethylamino)-ethylamino]-propyl (H(2)N-(CH(2))(2)-NH-(CH(2))(2)-NH-(CH(2))(3)-). Materials have been characterized by XRD, nitrogen sorption measurements and chemical analysis. We have found that all materials preserve the mesoscopic order and exhibit suitable textural properties and nitrogen contents to act as potential adsorbents. Metal removal from aqueous solution has been examined for Cu(II), Ni(II), Pb(II), Cd(II), and Zn(II); adsorption performances of materials prepared by the two functionalization methods have been compared. In addition, copper adsorption process has been thoroughly studied from both kinetic and equilibrium points of view for some selected materials. Aqueous Cu(II) adsorption rates show that the overall process is fast and the time evolution can be successfully reproduced with a pseudo-second-order kinetic model. Whole copper adsorption isotherms have been obtained at 25 degrees C. Significant maximum adsorption capacities have been found with excellent behavior at low concentration. 相似文献
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胆红素是由衰老及异常红细胞被吞噬、血红蛋白分解代谢产生的一种生物活性物质。采用具有小孔径和较大孔径两种介孔孔道的双介孔硅作为基底材料,并用葡萄糖醛酸对双介孔硅进行功能化,以实现对胆红素的选择性吸附。研究了吸附时间、温度、初始浓度、血清蛋白、离子强度对胆红素吸附的影响。实验结果表明,葡萄糖醛酸化双介孔硅对胆红素的吸附快速、高效,吸附平衡为15 min,最大吸附量为(246.78.3)mg/g,血清蛋白的存在对胆红素吸附的影响不大。胆红素吸附符合二级吸附动力学模型和Langmuir等温吸附模型。 相似文献
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Suk Bon Yoon Kuen-Woo Lee Jei-Kwon Moon Yong Suk Choi 《Journal of Experimental Nanoscience》2014,9(3):221-229
Hard template-based fabrication of mesoporous carbon unavoidably goes through the removal process of the template to generate template-free carbon replica, including troublesome disposal of template waste often accompanied by toxic etchant, which not only increases the fabrication cost of materials but also raises serious environmental concerns. As a novel strategy to overcome such problem, a direct in situ synthesis approach using silica waste in carbon/silica nanocomposite as a silica source and cetyltrimethylammonium bromide as a porogen under basic condition is reported in this study for the generation of a new composite composed of mesoporous MCM-41 silica and hollow carbon capsule. The resultant MCM-41/carbon capsule composite offers a 3-D interconnected multimodal pore system, which discloses a wide pore range of ordered uniform mesopores (ca 2.3?nm) resulting from MCM-41 silica and disordered uniform mesopores (ca 3.8?nm) and macropores (ca 300?nm) from hollow mesoporous carbon, respectively. The composite has a high specific surface area (ca 909?m2/g) and large pore volume (ca 0.73?cm3/g). The in situ transformation approach of silica waste into valuable mesoporous silica is considered as a promising scalable route for efficient new multi-functional composites useful for a wide range of applications such as adsorption of volatile organic compounds and radioactive wastes produced in a nuclear facility. 相似文献
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AbstractWe have developed composite hydrogels of chitosan (CS) and mesoporous silica nanoparticles (MSNs) in this study. The gelation rate, gel strength, drug delivery behavior and chondrocyte proliferation properties were investigated. The introduction of MSNs into CS accelerated the gelation process at body temperature and also increased the elastic modulus G′ from 1000 to 1800 Pa. When we used gentamicin (GS) and bovine serum albumin (BSA) as model small chemical drugs and biomacromolecules, respectively, the CS/MSN hydrogels released GS and BSA in a sustained manner simultaneously, but the CS hydrogels only showed sustained BSA release. Furthermore, in vitro chondrocyte culture showed that the CS/MSN composite hydrogels indeed performed much better in supporting chondrocyte growth and maintaining chondrocytic phenotype compared to the CS hydrogels. Therefore, the results suggest that the CS/MSN composite hydrogels can be potentially very useful for cartilage regeneration. 相似文献