共查询到20条相似文献,搜索用时 140 毫秒
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双亲水嵌段共聚物存在下特殊形貌的BaC2O4晶体合成 总被引:7,自引:0,他引:7
近年来 ,无机新型材料已经广泛应用于各个技术领域 ,而对于所合成材料的大小和形貌的调控已经成为该材料能够应用于催化、药物、电子、陶瓷、染料和化妆品等领域的一个关键因素[1 ] .利用水溶性有机添加剂作为晶体生长的诱导剂来控制无机晶体的形貌和晶型已有很多报道 .例如 :多种生物分子[2~ 5] 和普通合成的大分子添加剂[6] 对 Ca CO3 晶体在成核、晶化和生长过程中的晶型和形貌有着明显的控制作用 .近年来 ,双亲水嵌段共聚物的功能型高分子 (DHBC) [7]已经发展成为能够有效控制无机晶化过程的新型晶体生长的调控剂 .这类高分子通常是… 相似文献
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该文以更加接近生物矿化的方法研究了蔗糖/精氨酸体系对碳酸钙晶体取向、形貌和晶型的控制作用.XRD 分析表明,在蔗糖/L-精氨酸混合体系中合成的晶体主要为碳酸钙的球霰石晶型及少量的方解石型,在单独的蔗糖或L-精氨酸溶液中基本是球霰石晶型.SEM分析表明,蔗糖和L-精氨酸均可诱导形成特殊形貌的碳酸钙.实验结果表明,蔗糖/精... 相似文献
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利用仿生合成原理,选取天冬氨酸作为诱导剂,采用沉淀反应法制备出糖果状球霰石型碳酸钙粒子,并对其结构和性能进行了表征.考察了反应温度、诱导剂用量和反应时间等对碳酸钙粒子晶型和形貌的影响,探讨了其反应原理.结果表明,所得碳酸钙粒子荧光性增强.此方法对碳酸钙的仿生合成与改性研究具有一定的指导意义. 相似文献
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St / AA共聚物的组成对碳酸钙结晶及形貌影响的研究 总被引:1,自引:0,他引:1
在聚苯乙烯-丙烯酸两亲共聚物(简称PAS)溶液中制备CaCO3,用XRD、FTIR和SEM等研究随着PAS的亲水AA和亲油St单元组成的变化所引起的聚合物分子链段、溶解性质和胶束空间构象等的改变对CaCO3晶型和形貌的影响。结果显示:随着亲水性AA单元组成的提高,可以由AA链段的晶面匹配成核调控碳酸钙为方解石纳米晶,并因PAS在水溶液中溶解性不同,形成了多种碳酸钙形貌的聚集体;当St和AA的物质的量比为3∶1时,合成出类珍珠岩层碳酸钙结构。根据PAS的结构性质和在水溶液中的溶解行为初步探讨了类珍珠岩层碳酸钙的形成机理,认为是PAS基质模板和羧酸根对钙的键合作用形成这一特殊形貌碳酸钙。 相似文献
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25℃下,在鲫鱼牙齿提取液存在时,用Na_2CO_3和Ca(NO_3)_2·4H_2O作为原料合成碳酸钙,研究提取液的浓度和反应时间对产物组成和粒子形貌的影响。用粉末X-射线衍射仪(XRD)和红外光谱仪(FT-IR)对合成的产品进行了表征,用扫描电子显微镜(SEM)观察了粒子的形貌。研究结果显示,在反应时间是30s时,合成得到的产物是球霰石晶型和方解石晶型的混合物,并且随着提取液浓度的增加,球霰石所占比例呈现增加趋势;随着反应时间的增加,球霰石的含量会降低,但是产物粒子的形貌没有明显变化。结果说明,提取液的确能够影响碳酸钙的晶型和粒子形貌。 相似文献
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分别在90℃和120℃下,用2,2’-联苯二酸(bpdca)作为调控剂合成了具有不同晶型和形状Ca CO3晶体,研究羧酸浓度和温度对Ca CO3晶型和形貌的影响。用粉末衍射XRD、FT-IR表征了合成的产物,用扫描电子显微镜(SEM)观察研究了产物粒子的形状,调查研究了温度和bpdca浓度对Ca CO3粒子形貌和晶型的影响。结果表明,bpdca和温度均会对Ca CO3的晶型和形状有影响。 相似文献
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I. V. Shestak P. D. Vorob’ev D. V. Cherednichenko E. V. Vorob’eva G. V. Bondareva N. Strnadova 《Russian Journal of Inorganic Chemistry》2011,56(2):176-180
The effect of polyacrylic acid and polyethylene glycol on the crystallization of calcium carbonates in the presence of magnesium
ions was studied. It was found that the presence of magnesium ions in solution and the treatment temperature (80°C) influence
the formation of the final products of calcium carbonate crystallization. In binary mixtures, low-molecular-weight polyacrylic
acid and polyethylene glycol affect synergistically, and such mixtures can be used for selectively influencing the formation
of calcium carbonate polymorphs. 相似文献
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The calcium carbonate crystallization from aqueous solutions in the presence of alkali additives such as sodium hydroxide and ammonium hydroxide has been researched. It is found CaCO3 crystallizes predominantly in the modification of aragonite in the presence of ammonium hydroxide. The calcium carbonate formation rate in an alkaline medium and the gaseous reaction products due to sorption of gas bubbles on crystal surfaces, affect the aragonite structure formation. It is shown use of ammonium hydroxide for water treatment can solve two urgent tasks such as water softening and exclusion sediment of deposits on the equipment surfaces by a calcium carbonate crystallization in the form of aragonite. 相似文献
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Michael Maas Heinz Rehage Holger Nebel Matthias Epple 《Colloid and polymer science》2007,285(12):1301-1311
In this publication, we describe the growth of thin films of calcium carbonate beneath Langmuir monolayers of stearic acid.
The size and shape of the crystalline structures were systematically studied by means of different microscopic techniques
including Brewster angle microscopy, atomic force microscopy and scanning electron microscopy. In a series of experiments,
we explored the calcium carbonate crystallization process for different lipid monolayers and subphases. The observed phenomena
support a crystallization process which is induced by a thin, film-like structure of a precursor phase. The basic processes
of crystal and aggregate formation can be represented by a simple model which is based on electrostatic interactions between
the surfactant film and the inorganic calcium carbonate structures. 相似文献
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Freeman CL Harding JH Duffy DM 《Langmuir : the ACS journal of surfaces and colloids》2008,24(17):9607-9615
This paper presents simulations of calcium carbonate ordering in contact with self-assembled monolayers. The calculations use potential-based molecular dynamics to model the crystallization of calcium carbonate to calcite expressing both the (00.1) and (01.2) surfaces. The effect of monolayer properties: ionization; epitaxial matching; charge density; and headgroup orientation on the crystallization process are examined in detail. The results demonstrate that highly charged surfaces are vital to stimulate ordering and crystallization. Template directed crystallization requires charge epitaxy between both the crystal surface and the monolayer. The orientation of the headgroup appears to make no contribution to the selection of the crystal surface. 相似文献
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A detailed analysis of the effect of calcium carbonate nanoparticles on crystallization of isotactic polypropylene (iPP) is reported in this contribution. CaCO3 nanoparticles with different crystal modifications (calcite and aragonite) and particle shape were added in small percentages to iPP. The nanoparticles were coated with two types of compatibilizer (either polypropylene-g-maleic anhydride copolymer, or fatty acids) to improve dispersion and adhesion with the polymer matrix.It was found that the type of coating agent used largely affects the nucleating ability of calcium carbonate towards formation of polypropylene crystals. CaCO3 nanoparticles coated with maleated polypropylene can successfully promote nucleation of iPP crystals, whereas the addition of nanosized calcium carbonate coated with fatty acids delays crystallization of iPP, the effect being mainly ascribed to the physical state of the coating in the investigated temperature range for crystallization of iPP, as well as to possible dissolution by fatty acids of heterogeneities originally present in the polypropylene matrix. 相似文献
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I. A. Pochitalkina P. A. Kekin A. N. Morozov I. A. Petropavlovskii D. F. Kondakov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2016,90(12):2346-2351
The formal kinetics of calcium carbonate crystallization in aqueous solutions is studied at a stoichiometric ratio of Ca2+ and CO32- ions. The kinetics of the process was monitored by convenient and reliable methods (complexometric analysis for calcium in an aqueous solution and energy dispersive and microscopic measurement of solid particle sizes). The effect the temperature and degree of supersaturation have on the periods of induction and mass crystallization and the equilibrium concentration of calcium ions in solution is estimated at continuously controlled pH and solution ionic strength. The kinetic parameters (n, k, τ1/2, Ea) of calcium carbonate crystallization are calculated. It is shown that calcium carbonate with a calcite structure formed at a stoichiometric ratio of reagents, and changes in the temperature (25–45°C) and the solution’s degree of supersaturation (2–6) within the considered range had no effect on the characteristics of the solid phase. 相似文献
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A. V. Fakhreeva V. N. Gusakov A. I. Voloshin Yu. V. Tomilov N. E. Nifant’ev V. A. Dokichev 《Russian Journal of Applied Chemistry》2016,89(12):1955-1959
Sodium-carboxymethylcellulose inhibits the crystallization of calcium carbonate and sulfate on the surface of stainless steel in a supersaturated aqueous solution at 80°C. An increase in the size of calcium carbonate crystals and a change of their structure is observed in the presence of sodium-carboxymethylcellulose. The data obtained indicate that development of new “green” reagents for oil and gas extraction, scale inhibitors, on the basis of sodium-carboxymethylcellulose is promising. 相似文献
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F. G. Ishmuratov E. I. Koptyaeva A. I. Voloshin A. G. Telin Yu. V. Tomilov N. E. Nifant’ev V. A. Dokichev 《Russian Journal of Applied Chemistry》2015,88(12):1920-1922
Arabinogalactan inhibits the crystallization of calcium carbonate on the surface of stainless steel in a supersaturated aqueous solution at 80ºC. In the presence of arabinogalactan, the size of calcium carbonate crystals decreases and their structure changes. Arabinogalactan is a “green” scaling inhibitor. 相似文献
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Morphological control of calcium carbonate crystallized in reverse micelle system with anionic surfactants SDS and AOT 总被引:4,自引:0,他引:4
The influence of a surfactant over water on the polymorphism and crystal size of calcium carbonate produced by reaction crystallization in microemulsion systems was investigated in a mixing tank reactor. The crystallization was induced by the reaction between two aqueous micelle solutions (Na2CO3-CaCl2) stabilized by anionic surfactants, SDS (sodium dodecyl sulfate) or AOT (sodium bis(2-ethylhexyl) sulfosuccinate). With increasing surfactant ratio to water, the water-in-oil microemulsion was stably developed and the morphology of the calcium carbonate crystallized in the micelles sharply transformed from calcite to vaterite. The influence of SDS on the polymorphism and crystal size of calcium carbonate was much clearer than that of AOT. In addition, with AOT, certain step changes in the morphology and crystal size occurred around a surfactant ratio to water (R=[H2O]/[surfactant]) of 15 due to a two-phase separation of the microemulsion. 相似文献
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Liang P Shen Q Zhao Y Zhou Y Wei H Lieberwirth I Huang Y Wang D Xu D 《Langmuir : the ACS journal of surfaces and colloids》2004,20(24):10444-10448
This paper presents the crystallization behavior of calcium carbonate at the air/liquid interface of aqueous systems of carboxymethyl chitosan (CMCS) using the Kitano method. Although the synthesized CMCS (Mw approximately 100,000) with 1.57 degree of carboxymethyl substitution shows no surface activity, it controls the crystallization of calcium carbonate to form a petunia-shaped superstructure. The shuttlecock-like head of this superstructure strongly supports Colfen's opinion (Rudloff, J.; Colfen, H. Langmuir 2004, 20, 991-996) for the existence of a gas template of CO2 bubbles temporarily captured by polymer molecules, while formation of the stem of this superstructure is provisionally attributed to the presence of the strong electrostatic interactions between calcium ions and the carboxylate groups. The CaCO3 superstructure and its morphology depend not only on the polymer concentration but also on the combined number of calcium ions per CMCS molecule. These results imply that this simple and versatile method expands the morphological investigation of mineralization processes. 相似文献