共查询到19条相似文献,搜索用时 293 毫秒
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在前期利用模板剂法制备层状纳米羟基磷灰石(nano-hydroxyapatite,n-HA)的基础上,利用透射电子显微镜、X射线衍射和Fourier变换红外光谱等研究并讨论工艺参数对材料结晶性能影响以及形成机理。结果表明:反应24h后,HA晶体形成且层状结构清晰;在碱性条件下,生成的产物主要是n-HA,酸性条件下则生成CaHPO4;乙醇与水的质量比为2.0时,纳米晶体形状、大小相对均一。工艺参数的变化会影响表面活性剂的堆积参数,沿着表面活性剂模板生长的羟基磷灰石颗粒有不同的微观结构及形貌。 相似文献
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采用溶胶-凝胶水热法,调控反应参数和反应工艺制备SBA-15介孔材料。通过扫描电镜、透射电镜、X射线衍射以及氮气吸附-脱附分析表征表明,在一定范围,随着表面活性剂浓度增加,介孔材料SBA-15形貌出现由球形、陀螺形到米粒状的变化,介观有序度提高。在反应物料P123与Si物质的量比为0.012时,介孔材料的物性常数如晶面间距、比表面积、孔体积和最可几孔径较小。采用静态陈化-水热法研究不同表面活性剂浓度对介孔材料形貌演变的影响,为有效调控SBA-15介孔材料形貌提供必要依据。 相似文献
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采用CTAB/正戊醇/正辛烷/水反相微乳液体系,制备了BaF2纳米粉体.研究了微乳液体系中(水与表面活性剂的摩尔比)对BaF2尺寸和形貌的影响.用扫描电子显微镜、X射线衍射仪表征样品的形貌和结构.结果表明:所得产物粒径为80nm~800nm. 相似文献
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Jing-Jing Dong Chun-Yang Zhen Hui-Ying Hao Jie Xing Zi-Li Zhang Zhi-Yuan Zheng Xing-Wang Zhang 《Nanoscale research letters》2013,8(1):378
In this paper, controllable synthesis of various ZnO nanostructures was achieved via a simple and cost-effective hydrothermal process on the Si substrate. The morphology evolution of the ZnO nanostructures was well monitored by tuning hydrothermal growth parameters, such as the seed layer, solution concentration, reaction temperature, and surfactant. X-ray diffraction and photoluminescence measurements reveal that crystal quality and optical properties crucially depend on the morphology of the ZnO nanostructures. The ease of synthesis and convenience to tune morphology and optical properties bring this approach great potential for nanoscale applications. 相似文献
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多晶硅生产中主要副产物四氯化硅副产量大、腐蚀性强、难以安全处理。笔者以四氯化硅为原料,在表面活性剂存在下制备二氧化硅。研究了物料比例、反应温度、加料速率等因素对产品比表面及产率的影响,采用红外光谱仪、X射线衍射仪、比表面积测定仪和扫描电子显微镜对晶体结构、比表面积、产品的形貌进行了表征。结果表明,采用质量浓度0.5 g/L的十二烷基苯磺酸钠(SDBS)溶液为反应底物、四氯化硅加入量为1.5 mol/L(底物)、反应温度为45℃、加料速率为0.35 mol/h,反应混合物具有较好的过滤性能,并可得到粒径分布窄的二氧化硅产品,产品收率可达80%。 相似文献
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Hongxia Lu Xiujun YuZhaohuan Zeng Deliang ChenKe Bao Liwei Zhang Hailong WangHongliang Xu Rui Zhang 《Ceramics International》2011,37(1):287-292
ZnO nanowhiskers were successfully fabricated using DC-field induced water-in-oil microemulsions method. Phase structure, morphology and microstructure of the product were investigated by X-ray diffraction and transmission electron microscopy. Parameters in preparation process such as electric field intensity and surfactant were discussed and the product formation mechanism was studied. XRD and TEM results showed that the obtained ZnO particle was hexagonal wurtzite-type with 1-3 nm in diameter and 20-70 nm in length, and morphology of the particles was shown to be correlated not only with the electric field intensity but also with the surfactant. There was a threshold when the electric field intensity was 80 V/mm. The morphology of the particles was basically spherical before the threshold, while L/D increased with the raise of electric field intensity. ZnO nanowhiskers were obtained under mixed surfactants but spherical particles were got with a single surfactant. 相似文献
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Zhitong Zhao Wenpeng Shan Yunfei Zhang Xiangde Li Jian Ma Yonggang Yan 《应用聚合物科学杂志》2012,125(4):2502-2509
Poly(amino acid)/nano hydroxyapatite (PAA/n-HA) bioactive composite was prepared by in situ melting polymerization. The composition, structure and morphology as well as glass transition temperature (Tg), dynamic mechanical properties of the PAA/n-HA composite were characterized by infrared spectrometer, X-ray diffractometer, X-ray photoelectron spectroscopy, scanning electron microscope, differential scanning calorimeter, and dynamic mechanical analyzer. The results indicated that the n-HA particles were uniformly distributed into PAA matrix and some interactions were found at the interface between PAA and n-HA, and the crystallinity of PAA in the composite decreased with the increase of n-HA content. The Tg and storage modulus of the composite increased with increasing n-HA content, demonstrating that the n-HA content had obvious effects on the crystallization kinetic parameters and thermo properties of the PAA/n-HA composite. In addition, the n-HA amount had evident effects on the degradation of the PAA/n-HA composite in phosphate buffered saline (PBS), and the weight loss ratio of the composite decreased with the increase with n-HA content. The pH value of the medium was stable around 7.40 after the composite immersion into PBS for 8 weeks. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
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Haojie Ding Liuyun Jiang Chunyan Tang Shuo Tang Bingli Ma Na Zhang Yue Wen Yan Zhang Liping Sheng Shengpei Su Xiang Hu 《Frontiers of Chemical Science and Engineering》2021,15(3):630
To obtain nano-hydroxyapatite/poly(lactide-co-glycolide) (n-HA/PLGA) nanocomposite with superior mechanical properties, here, lignin was chosen to surface-modify for n-HA through co-precipitation method. The different reaction conditions of reaction time, phosphorus source, and the lignin addition amount were studied by fourier transformation infrared spectra, X-ray diffraction, the intuitionistic dispersion experiment, transmission electron microscope and thermal gravimetric analysis. The reaction mechanism and the best appropriate reaction condition were obtained. More importantly, the results of electromechanical universal tester, scanning electron microscope, differential scanning calorimetric analyzer, polarized optical microscopy and dynamic mechanical analysis confirmed that the obtained n-HA could greatly increase the mechanical strength of PLGA, owing to the excellent dispersion and promotion crystallization effect. Moreover, in vitro cell culture experimental results indicated that the n-HA surface-modified by lignin was favorable to improve the cell biocompatibility of PLGA. The study suggested that the introduction of lignin was a novel method to acquire a highly dispersed n-HA, which would provide a new idea to achieve the n-HA/PLGA nanocomposite as bone materials in future, and it would pave the way towards a new application of lignin in biomedical field. 相似文献
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以二氧化钛(TiO2)和八水合氢氧化钡[Ba(OH)2·8H2O]为原料,采用水热合成法,成功制备出具有四方相晶型和空心形貌结构的钛酸钡粉体。利用透射式电子显微镜(TEM)和X射线衍射(XRD)对样品的形貌结构和晶型做了表征,通过研究反应过程中钛酸钡粉体的结构和晶型随时间的变化过程,对空心钛酸钡的形成机理做了详细的探讨,并考察了不同反应温度和钡浓度对钛酸钡粉体结晶和生长的影响。研究结果表明:反应温度和钡浓度会影响钛酸钡粉体的晶型和形貌,并以此提出了一种空心钛酸钡的形成机理;当反应温度为180 ℃、钡浓度为3.0 mmol/L时,能获得粒径分布均匀的四方相晶型的空心钛酸钡粉体。 相似文献
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研究了一种作为药物载体的多孔球形羟基磷灰石生物材料的制备工艺。采用微乳液法先制得多孔球形碳酸钙,并以此为模板与磷酸氢二钠在一定条件下反应制备出直径约10μm的多孔球形羟基磷灰石。通过X射线衍射,扫描电子显微镜等手段对制备的羟基磷灰石的结构、组成和形貌进行表征,考察了不同反应温度、表面活性剂浓度、反应时间对多孔球形貌的影响,并对反应机理进行了初步探讨。结果表明,当制备多孔球形碳酸钙模板的温度为25℃、吐温-80浓度为3%且碳酸钙与磷酸氢二钠反应时间为30h时,得到的羟基磷灰石为5-10μm、分散性好的球形晶体。 相似文献
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采用天然棉花为模板制备了具有高光催化活性的SnO2/ZnO复合中空纤维光催化材料;利用X-射线衍射(XRD)、扫描电子显微镜(SEM)技术对其相结构和形貌进行了表征;以亚甲基蓝(MB)的脱色降解为模型反应,考察了Sn4+和Zn2+物质的量比为0.1∶1时煅烧温度对其催化性能的影响。实验结果表明:制备的样品为复制了棉花纤维模板形貌、具有中空结构的SnO2和ZnO半导体复合材料(SnO2/ZnO);煅烧温度对材料SnO2/ZnO的结晶度、晶粒大小﹑表面微结构和催化性能等有显著影响;650℃左右所得样品在太阳光下的催化活性最好,1 h可使MB溶液的脱色降解率达100%;该材料易于离心分离,具有良好的催化活性和重复使用性能。 相似文献
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Douglas M. Fox Richard H. Harris Jr. Jeffrey W. Gilman Mikhail Y. Gelfer Benjamin S. Hsaio Paul H. Maupin Paul C. Trulove 《Polymer》2011,52(23):5335-5343
A polyhedral oligomeric silsesquioxane (POSS) tethered imidazolium surfactant was used to exchange montmorillonite for the preparation of polymer nanocomposites in polystyrene, poly(ethylene-co-vinyl acetate), and polyamide-6 using a melt blending technique. Simultaneous temperature resolved small angle X-ray scattering and wide angle X-ray diffraction was used to monitor the surfactant stability and phase behavior of the polyamide-6 nanocomposites. Good thermal stability of the surfactant was in agreement with thermogravimetric analysis. Transmission electron microscopy revealed a mixed intercalated/exfoliated structure, with the presence of small tactoids exhibiting gallery spacings greater than 3.8 nm in all three polymers. Fluorescently tagged organically exchanged montomorillonite was used to assess the quality of nanoparticle dispersion. Exchanging the montmorillonite with lower loadings of the POSS surfactant slightly increased the size of clay tactoids, but did not significantly alter the gallery spacing or overall dispersion. The results suggest that the bulky and rigid structure of POSS, as well as its tendency to aggregate into ordered crystals, form a bilayer structure in the clay galleries and prevent montmorillonite from completely exfoliating, even in polyamide-6. 相似文献