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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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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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反应条件对乳液法自组装合成氧化锰纳米粒子结构、形貌和尺寸的影响 总被引:1,自引:0,他引:1
通过改变反应物物质的量比、分散相与连续相体积比、反应体系温度和煅烧后处理温度,研究了反应条件对乳液法自组装合成氧化锰纳米粒子结构、形貌和尺寸的影响.结果表明:当高锰酸钾与油酸物质的量比在1∶5~1∶1之间时,形成蜂窝状纳米粒子和空心纳米粒子;当分散相(油酸)与连续相(水)的体积比为4∶200时,形成良好的空心球纳米结构;反应体系温度升高不利于产物的洗涤;不同温度的煅烧后处理不仅影响氧化锰纳米粒子的形貌,而且影响其结晶度和晶型. 相似文献
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枝状文石型碳酸钙的仿生合成及在PVC中的应用 总被引:1,自引:0,他引:1
利用生物矿化原理,以聚丙烯酸(PAA)为有机基质,采用碳化法合成了具有枝状形貌的文石型碳酸钙粒子.通过场发射扫描电镜(FESEM)、X射线衍射仪(XRD)和傅里叶变换红外光谱仪(FTIR)等检测手段研究了产物的结构和形貌,并初步探讨了粒子的生长机理.结果表明,在文石型碳酸钙粒子的合成中,有机基质和反应温度是非常重要的参数.同时将该产品填充于聚氯乙烯(PVC)中,测定了PVC塑料的力学性能和加工性能. 相似文献
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以在不同的热处理温度下合成的具有可变化学结构的碳点(CDs)为添加剂调控合成矿物碳酸钙。在室温条件下合成了花生状、哑铃状和球形碳酸钙颗粒。用扫描电镜(SEM)、傅里叶红外光谱仪(FTIR)、荧光光谱仪(PL)和X射线衍射仪(XRD)对样品进行了表征,详细研究了碳酸钙双球粒子的生长过程。CDs表面随处理温度可调变的极性官能团(主要为羧基、醛基、羟基等)被认为是导致合成碳酸钙粒子形貌变化的原因。对碳酸钙双球粒子的生长机理研究表明,Ostwald成熟和定向聚集机制是在CDs存在下最终双球粒子形貌形成的驱动力。 相似文献
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Inspired by mineralization in biological organisms, fabrication of higher ordered CaCO(3) crystals modified by surfactants has received much attention. In our present work, mixed surfactants of hexadecyl(trimethyl)azanium bromide and sodium dodecyl sulfate were used to mediate the nucleation and growth of CaCO(3) crystals. When the concentration of sodium dodecyl sulfate in the solution is constant (0.1 mM), the polymorph of CaCO(3) crystals changed from pure vaterite to pure aragonite with increase of the ratio of hexadecyl(trimethyl)azanium bromide to sodium dodecyl sulfate. Various morphologies of vaterite and aragonite were obtained. Based on the time-resolved experiments, we suggest that the flower-like CaCO(3) formed via aggregation of hexagon-like vaterite induced by the surfactants. More importantly, we realized that a cluster-shaped morphology of aragonite was produced through the nucleation of aragonite at the surfaces of the hexagon-like vaterite. 相似文献
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CaCO3 crystallization on a chitosan membrane was studied using diffusion of (NH4)2CO3 vapors into a CaCl2 solution containing differing added amounts of two polyacrylic acids (PAAs) with molecular weights of ca. 2.0 x 10(3) and ca. 4.5 x 10(4). The coexistence of PAA and the chitosan membranes produced thin CaCO3 island crystals, which developed into a continuous CaCO3 film on the membranes. Continuous CaCO3 films consisting of only aragonite formed on the chitosan membranes at the optimum amount of PAA. When the amount of PAA is not optimum, the polymorph of CaCO3 switches from aragonite to vaterite, and the morphology has a tendency to become an isolated island structure. The formation of the aragonite and vaterite island crystals and the appearance of a range of added PAA suitable for their formation are explained by the action of two parallel phenomena: (a) the high concentration of Ca2+ ions in the chitosan membrane vicinity is achieved by the interaction between the -COO- groups of PAA adsorbed by the -NH3+ groups of the chitosan membrane through an electrostatic force and free Ca2+ ions in the CaCl2 solution, which produces the high supersaturation with CaCO3 in the membrane vicinity during CO2 diffusion; (b) PAA, remaining as mobile carboxylic anions in the CaCO3 solution, inhibits the growth of the CaCO3 island crystals by its adsorption. The CaCO3 supersaturation in the membrane vicinity is controlled by regulating the balance of these phenomena, which leads to the formation of the desired CaCO3 polymorph. 相似文献
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在不加任何结晶控制剂或模板条件下,以CaCl2和Na2CO3为原料,利用复分解反应法制备了具有较好形貌和高长径比,且分布均一的文石型碳酸钙晶须,并利用扫描电镜(SEM)、X-射线粉末衍射(PXRD)和傅里叶转换红外光谱图(FT-IR)等手段对其进行了表征。研究了浓度、滴加速度、反应温度、搅拌速度以及滴加方式等因素对碳酸钙晶须的影响。结果表明最佳制备工艺为:CaC12溶液与Na2CO3溶液的浓度为0.05 mol.L-1,溶液滴加速度为1 mL.min-1,反应体系温度为80℃,搅拌速度为250 r.min-1。 相似文献
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ZhiGuoHU ShiLiSONG JianJiWANG LinYANG 《中国化学快报》2004,15(6):707-710
In this paper, the effect of ionic liquids on the CaCO3 crystal growth has been studied for the first time. The obtained CaCO3 crystals were charactcred by the X-ray diffraction and scanning electron micrographs. The results showed that the control ability of ionic liquids for CaCO3 crystals growth was dependent on the counter anion very much. 相似文献
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Carbon nanotubes were used to induce the formation of spherical vaterite crystals and stabilize the metastable crystals in the biomimetic mineralization of CaCO3 for the first time. It was found that carboxyl-functionalized multiwalled/single-walled carbon nanotubes (MWNT-COOH/SWNT-COOH) can favor the formation of spherical vaterite crystals and stabilize the crystals. In the presence of CNT-COOH, CaCO3 vaterite crystals with diameters of ca. 1-7 microm coated and embedded with the carbon nanotubes (CNTs) were obtained in 30 min by adding Na2CO3 aqueous solution to the aqueous solution of CaCl2. The spherical vaterite crystals covered by the carboxylic CNTs can exist stably in water for a week. Carboxylic-polymer-functionalized CNTs can also facilitate the formation of spherical vaterite crystals, whereas the formed crystals completely transformed into thermodynamically stable calcite crystals in water within 10 h. "Offline" TEM observations of the mineralization process of CaCO3 in the presence of CNT-COOH or pristine CNTs revealed the stability mechanism of vaterite crystals with carboxylic CNTs. The crystals nucleate at the carboxyl groups of CNT-COOH, grow around the CNTs, and finally form spherical vaterite crystals embedded and covered by the CNTs. The strong interaction between CNT-COOH and crystals together with the strong mechanical strength of CNTs stabilizes the formed vaterite crystals and makes them difficult to dissolve in water. These findings announce that nanomaterials could strongly influence the mineralization of biomineralization matters, which may help us prepare novel biomaterials and bionanomaterials. 相似文献
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Müller H Zentel R Janshoff A Janke M 《Langmuir : the ACS journal of surfaces and colloids》2006,22(26):11034-11040
In this paper we describe how to template a demixed monolayer into a spatially patterned inorganic replica. For this purpose a new amphiphilic monomer was synthesized which can be polymerized both in solution and in the monolayer of a Langmuir-Blodgett (LB) trough. Since it inhibits the crystallization of CaCO3, it can be used--in combination with stearic acid (nucleation-promotor)--to control CaCO3 crystals formed under the monolayer. Investigations of the two-component monolayer (Langmuir isotherms and AFM measurements of transferred films) show--in the biphasic region--demixing in solid analogue stearic acid domains and the liquid analogue phase of the monomer. Crystallization of CaCO3 starts under the stearic acid domains whose size varies from less than 100 nm to several tens of micrometers. The addition of poly(acrylic acid) into the subphase hinders the three-dimensional growth of CaCO3 crystals from the monolayer into the solution. Thus, it becomes possible to transfer the pattern of the demixed domains into an inorganic replica of CaCO3. 相似文献
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以十二碳醇磷酸酯(DDP)为改性剂, 采用碳化法制备了分散性良好的球状碳酸钙粒子. 通过FESEM, XRD, FTIR及活化度和接触角测试对产物进行了表征. XRD分析结果表明, 随着DDP添加量的增加, 所得CaCO3由方解石型向文石型转变. FTIR结果表明, 改性剂与碳酸钙表面是以化学键合和物理吸附方式相结合. 当DDP含量达到2%时, 接触角为120.43°, 活化度达到99%, 碳酸钙粒子由亲水性转变为完全疏水性. 考察了反应温度和DDP含量对产物形貌与结晶行为的影响, 并对改性机理进行了初步探讨. 将产品填充到聚丙烯(PP)中, 测定了PP的力学性能. 相似文献
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The effects of seven carboxylic acids, i.e., acrylic acid, maleic acid, tartaric acid, malic acid, succinic acid, and citric acid, on CaCO(3) crystallization were studied using the unseeded pH-drift method along with a light-scattering technique. Experiments were started by mixing solutions of CaCl(2) and NaHCO(3) in the presence or absence of additives. The crystallization was studied by recording the decrease in pH resulting from the reaction Ca(2+)+HCO(3)(-)-->CaCO(3)+H(+). A given amount of carboxylic acid was added to the solution of CaCl(2) or NaHCO(3) before mixing the reactants. The pH profiles obtained in the case of the CaCl(2) solution containing an additive were similar to those for the NaHCO(3) solution containing one, and when an additive was added after the onset of crystallization, the growth of CaCO(3) immediately stopped. The light-scattering observations, in all cases, indicated that CaCO(3) nucleation occurred at 10-20 s after mixing of the reactants. The results indicated that the nucleation of CaCO(3) was not influenced by the presence of carboxylic acids, but CaCO(3) crystal growth was reduced by their adsorption to the surface of the CaCO(3) crystals. These phenomena were explained by assuming a stronger affinity of the carboxylic acids for CaCO(3) particles than for the free Ca(2+) ions in solution. The crystallization of CaCO(3) in the presence of additives was divided into three stages: nucleation, growth incubation, and growth periods. Copyright 2001 Academic Press. 相似文献
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孪生球状碳酸钙的直接混合沉淀法制备及表征 总被引:3,自引:0,他引:3
以醋酸钙和碳酸钠为原料, 柠檬酸三钠为晶形控制剂, 利用液相直接混合沉淀法合成了分散性好、粒度约1.5~3.0 μm、长短轴比约2∶1的孪生球形碳酸钙晶体. 利用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、傅里叶红外光谱仪(FTIR)、原子力扫描探针显微镜(ASPM)和粒度分析仪等对样品进行了表征. 结果表明, 在不添加柠檬酸三钠的溶液中得到微米级的立方状碳酸钙晶体, 而添加柠檬酸三钠(质量分数30%~40%)后则得到具有不同表面粗糙度的孪生球状碳酸钙晶体. 同时, 用分形生长理论和成核限制聚集(NLA)模型对孪生球状碳酸钙粒子的形成机理进行了分析. 相似文献