杜邦公司超细二氧化钛生产工艺

据《AdditiceforPolymers》1998，NO11，P8报道，美国杜邦（DuPout）公司开发出一种新的超细二氧化钛（TiO2）粒子生产工艺，粒子特点为光学上透明，但仍保持对紫外线辐射的阻隔性。生产工艺由该公司特殊化学集团独立环发，用氨基草酸钛作为起始化合物，采用水热（hydIDth。DiaO工艺，仅生成金红石型粒子，不象其他工艺生成金红石型和锐钛型二氧化钛的混合物，另外不需再进行锻烧，假烧阶段要增加生产成本，而且会生成二氧化钛聚集体，降低二氧化钛粒子的透明性。用这种工艺生成的超细二氧化钛粒子大小分布均匀，不大于100纳米（urn人…     

一种低紫外辐射灯具玻壳的制备与性能研究

采用溶胶-凝胶法制备金红石型纳米TiO_2,在制备中间过程中加入CeO_2,制备出金红石型纳米TiO_2-CeO_2复合紫外吸收剂,研究了TiO_2与CeO_2的最佳配比。在玻璃制备过程中加入金红石型纳米TiO_2-CeO_2复合紫外吸收剂,研制出低紫外辐射灯具玻壳。同时研究了复合紫外吸收剂加入量对灯具玻壳紫外吸收性能和其他理化性能的影响。     

室温下二氧化钛晶相可控新技术

锐钛型二氧化钛可用作抗菌剂;金红石型二氧化钛可用于光伏电池、智能传感器、光通信技术等领域,但是获得相稳定的二氧化钛对研究者来说一直是个难题。低于500℃时,二氧化钛材料会转化成锐钛型,高于500℃时则转化成金红石型。针对这一问题,美国北卡罗拉纳州大学材料科学与工程学院Jay Narayan博士及其团队开发了一种可在常温下精确     

金红石型纳米钛白粉在车辆涂料中的应用

介绍了金红石型纳米二氧化钛在丙烯酸金属烘干漆中的应用,通过将有机光稳定剂及不同比例的金红石型纳米二氧化钛加到丙烯酸金属烘干漆中,并检测其相应的性能,观察金红石型纳米二氧化钛对涂膜的耐候性、硬度、附着力、颜料沉淀以及金属闪光漆的随角异色效果的影响。     

钛-铝合金表面二氧化钛纳米管的制备及生物矿化

采用电化学阳极氧化在钛-铝合金表面生成一层结构高度有序的二氧化钛纳米管阵列,并在模拟体液中进行生物矿化实验。利用扫描电子显微镜和X-射线衍射仪对TiO2纳米管的结构形貌以及通过生物矿化生成的羟基磷灰石涂层进行了表征。实验结果表明,钛-铝合金表面的TiO2纳米管直径为80～100nm,管长约1μm。在模拟体液中的矿化实验结果证明在TiO2纳米管上沉积了羟基磷灰石涂层。     

纳米金红石型二氧化钛胶体制备包核二氧化钛

通过几种不同包核二氧化钛制备方法比较,进行了纳米金红石型二氧化钛胶体制备包核二氧化钛工艺过程的探索,结果表明:采用我国储量丰富的低价的矿石粉(如高岭土、硅石粉、云母粉、碳酸钙、硫酸钡等)作为包核二氧化钛的内核原料,以纳米金红石型二氧化钛胶体为包核主原料,工艺简单,成本低,环保治理简便,废水经处理后可循环使用,产品品质优良,白度、遮盖力、吸油量等性能指标接近二氧化钛标准,能替代二氧化钛应用于涂料、造纸、橡胶和塑料等领域.     

氧化铝基板上二氧化钛纳米棒薄膜的形貌及其润湿性的研究

使用溶胶凝胶法在氧化铝基板上涂敷一层二氧化钛溶胶,煅烧后形成诱导层,随后用水热法在诱导层上生长纳米棒,研究水热前驱液中钛酸四丁酯(TBOT)浓度对二氧化钛纳米棒薄膜生长的影响,用XRD、SEM、TEM对样品的结构和形貌进行了表征,使用接触角测量仪测试样品的润湿性。测试结果表明:涂敷诱导层可以让氧化铝基板上生长出致密的单晶生长的金红石相二氧化钛纳米棒薄膜,生长的晶面方向为(0,0,1);当水热前驱液中钛酸四丁酯浓度逐渐增大时,基片表面先是生成棒状二氧化钛,与水的接触角逐渐增大,最高可达到102.475°,随后纳米棒逐渐聚集,生成集束状和球状二氧化钛,接触角开始减小,最小可达到4.455°。     

Materials Studio在材料模拟中的应用——以TiO2晶体为例

二氧化钛具有三种主要的晶型,金红石型,锐钛矿型和板钛矿型,三种晶型的结构不同,因此性质也不同。本文将使用Materials Studio中的CASTEP程序对二氧化钛三种晶型进行模拟,并测量不同晶型中体系的能带结构和态密度。     

硬硅钙石复合隔热涂料制备与隔热性能测试

以硬硅钙石作阻隔型填料,以金红石型二氧化钛和中空玻璃微珠为反射型功能填料,制备建筑外墙隔热涂料。研究了单掺硬硅钙石、金红石型二氧化钛、中空玻璃微珠以及复合添加3种填料对涂层隔热性能的影响。结果表明:单掺硬硅钙石、金红石型二氧化钛或中空玻璃微珠均可提高涂层隔热性能,硬硅钙石的适宜掺量为9%,金红石型二氧化钛的适宜掺量为30%,空心玻璃微珠的适宜掺量为20%;复合掺入硬硅钙石、金红石型二氧化钛和空心玻璃微珠可进一步提高涂层隔热性能,掺量为9%、30%和15%时,涂层的热反射率可达93.69%。按建筑行业标准JG/T235—2008《建筑反射隔热涂料》进行检测,涂料对波长为250～2 500 nm范围内的太阳反射比为0.85,半球发射率为0.87,隔热温差为13℃,符合标准要求;空心玻璃微珠、二氧化钛和硬硅钙石复合掺入后,发挥协同作用,能更加有效地提高涂层的隔热性能。     

二氧化钛相变研究现状

综述了二氧化钛由锐钛矿型向金红石型转变的影响因素,重点研究了温度调控与添加剂调控对二氧化钛锐钛矿型向金红石型转变的影响和作用机理。结果表明：温度调控能直接有效地促进二氧化钛锐钛矿型向金红石型转变;掺杂熔点低于TiO2的金属氧化物V2O5、SnO2等,离子半径与Ti4+半径相近的Fe3+、V4+、Ce4+等,以及体积小的低价阴离子Cl-、F-等都能促进TiO2由锐钛矿型向金红石型转变。     

两步电化学法制备羟基磷灰石/氧化铝复合生物涂层的研究

研究旨在开发一种可应用于医用金属表面生物学改性的复合生物陶瓷涂层。通过先阳极氧化、再电沉积的两步电化学方法成功制备了羟基磷灰石(hydroxyapatite,HA)／Al2O3复合生物涂层。利用扫描电子显微镜(SEM)研究了阳极氧化Al2O3(anodic aluminum oxide,AAO)膜的表面形貌与HA／Al2O3复合涂层的表面及截面形貌结构;用X射线衍射仪(XRD)、Fourier变换红外光谱仪(FT-IR)与能谱仪(EDS)表征了复合涂层的物相组成;用等离子原子发射光谱仪(ICP-AES)和粘接拉伸试验分别测定涂层在模拟体液(SBF)中的体外行为和浸渍后涂层间的结合强度,结果表明：所制备的HA含有少量碳酸根,在SBF中呈现优良的稳定性并能诱导新的磷灰石层的形成;HA底部嵌入AAO膜的孔洞中形成互锁界面,经模拟体液处理后两者之间结合强度为3．2MPa。     

以葡萄糖为造孔剂制备多孔羟基磷灰石涂层

采用电泳沉积方法在钛基材表面制得羟基磷灰石(hydroxyapatite,HA)/葡萄糖复合涂层,经烧结处理得到多孔HA涂层。采用红外光谱仪、扫描电镜、X射线衍射和热重分析表征了涂层的组成、表面形貌、物相组成及热稳定性,黏结-拉伸实验测定涂层与基体的结合强度,人体模拟体液(simulated body fluid,SBF)浸泡测定涂层的生物亲合性。结果表明:经700℃烧结处理,复合涂层中的葡萄糖微粒热分解得到多孔HA涂层,孔径为2～20μm,涂层与基体的结合强度可达17.6MPa;在1.5倍SBF(各离子浓度为SBF的1.5倍)中浸泡5d后,多孔HA涂层表面碳磷灰石化,呈现良好的生物亲合性。     

溶胶-凝胶法与两步沉淀法制备的镁黄长石粉体的体外生物活性比较

通过溶胶-凝胶法和两步沉淀法分别合成镁黄长石(Ca2MgSi2O7)粉体,并通过模拟体液浸泡对这两种方法合成的镁黄长石的体外生物活性进行比较。用X射线衍射、扫描电镜、原子发射光谱(ICP-AES)以及pH计分别对浸泡后形成的羟基磷灰石的物相、形貌以及浸泡后模拟体液的离子浓度变化、pH值进行表征。结果表明：两步沉淀法合成的镁黄长石在浸泡5d后就能明显检测到羟基磷灰石生成,而溶胶-凝胶法合成的镁黄长石在浸泡7d后才能检测到羟基磷灰石生成;两步沉淀法合成的镁黄长石诱导的羟基磷灰石呈结晶较好的虫状结构,而溶胶-凝胶法合成的镁黄长石诱导的羟基磷灰石呈结晶不完整的圆形颗粒结构;而且,两步沉淀法合成的镁黄长石具有更快的Ca离子释放能力。因此,两步沉淀法合成的镁黄长石相对于溶胶-凝胶法合成的镁黄长石具有更好的诱导羟基磷灰石形成能力和生物活性。     

Evaluation of ascorbic acid-loaded calcium phosphate bone cements: Physical properties and in vitro release behavior

In this study, different concentrations of ascorbic acid (50, 100 and 200 µg/mL) were added to the liquid phase of a calcium phosphate cement (CPC). The cements were immersed in simulated body fluid (SBF) for different intervals and physical, physicochemical and mechanical properties of them were evaluated. The release of added ascorbic acid from CPCs into the SBF solution was also studied. From the results, both setting time and injectability of CPC decreased by adding ascorbic acid, however the compressive strength was sharply increased before soaking in SBF solution. But, the compressive strength values of all cements (with or without ascorbic acid) soaked in SBF solution for more than 7 d duration were comparable. The X-ray diffractometry results showed that in vitro apatite formation ability of cement reactants did not change by adding ascorbic acid. The scanning electron microscopy images indicated that morphology of the formed apatite crystals was nano-needlelike and needle diameter was less than 100 nm. The loaded ascorbic acid was slowly released from CPC into the SBF solution so that about 10% and 20% of the loaded drug was released after 504 h for the cements containing 100 and 200 µg/mL ascorbic acid, respectively. The release rate was increased when the amount of added ascorbic acid decreased by 50 µg/mL.     

预钙化加速类骨磷灰石在镍钛合金表面生长的电化学阻抗谱

通过酸碱处理活化NiTi合金表面,在模拟体液中仿生生长类骨磷灰石层以改善其生物相容性.采用电化学阻抗谱研究了预钙化对加速磷灰石沉积的影响,并基于双层模型建立了电子等效电路.结果表明:随着在模拟体液中浸泡时间的延长,化学处理的NiTi合金表面类骨磷灰石不断生长,并且添加预钙化试样浸泡3 d,即可在合金表面生长出均匀完整的类骨磷灰石层,而未预钙化试样表面沉积物稀少.对应电子等效电路中,预钙化试样电阻值明显大于未预钙化试样的,显示预钙化促进了活化NiTi合金表面类骨磷灰石的生长.     

Biomimetic apatite deposited on microarc oxidized anatase-based ceramic coating

Biomimetic apatite was formed on a microarc oxidized (MAO) anatase-based coating containing Ca and P in a simulated body fluid (SBF). At the process of the SBF immersion (0–96 h), the Ca and P of the MAO coating dissolve into the SBF, increasing the supersaturation degree near the surface of the MAO coating, which could promote the formation and growth of apatite. After SBF immersion for 7 days, the surface of the MAO coating was modified slightly. The entire surface immersed for 14 days was covered by an apatite coating. The apatite possesses carbonated structure, controllable crystallinity and pore networks. The results indicate that the MAO coating formed in an electrolyte containing phosphate and EDTA–Ca chelate complex possesses good apatite-forming ability.     

Enhanced BMP-2-Mediated Bone Repair Using an Anisotropic Silk Fibroin Scaffold Coated with Bone-like Apatite

The repair of large bone defects remains challenging and often requires graft material due to limited availability of autologous bone. In clinical settings, collagen sponges loaded with excessive amounts of bone morphogenetic protein 2 (rhBMP-2) are occasionally used for the treatment of bone non-unions, increasing the risk of adverse events. Therefore, strategies to reduce rhBMP-2 dosage are desirable. Silk scaffolds show great promise due to their favorable biocompatibility and their utility for various biofabrication methods. For this study, we generated silk scaffolds with axially aligned pores, which were subsequently treated with 10× simulated body fluid (SBF) to generate an apatitic calcium phosphate coating. Using a rat femoral critical sized defect model (CSD) we evaluated if the resulting scaffold allows the reduction of BMP-2 dosage to promote efficient bone repair by providing appropriate guidance cues. Highly porous, anisotropic silk scaffolds were produced, demonstrating good cytocompatibility in vitro and treatment with 10× SBF resulted in efficient surface coating. In vivo, the coated silk scaffolds loaded with a low dose of rhBMP-2 demonstrated significantly improved bone regeneration when compared to the unmineralized scaffold. Overall, our findings show that this simple and cost-efficient technique yields scaffolds that enhance rhBMP-2 mediated bone healing.     

Effect of carbonate content on the in vitro bioactivity of carbonated hydroxyapatite

The effect of carbonate content on the apatite-forming ability of carbonated hydroxyapatite (CHA) in simulated body fluid (SBF) has been investigated. Five different nanocrystalline B-type CHA with carbonate content ranged from 2.01 to 5.25 wt% were prepared, sintered, and assessed for their in vitro bioactivity in SBF solution for 7-weeks under static conditions at 36.5 °C. The formation of the apatite layer and the surface morphology of CHA were examined by using a scanning electron microscope (FESEM) at week 1, 3, and 7 of SBF immersion, respectively. The Ca/P molar ratio of the CHA was determined by X-ray fluorescence (XRF). In addition, the sample weight changes and the pH of the SBF solution were measured. The results show that the formation of apatite layer depends on the carbonate content of CHA. Increasing the carbonate content caused significant increases in the surface area of CHA and the rate of apatite formation. Weight loss was observed for all CHA samples during the first week of SBF immersion, and thereafter followed by weight regain weekly until week 7. The changes in the pH of SBF and the Ca/P molar ratio were proportional to the carbonate content of CHA. This study thus highlights the importance of determining carbonate content aspect that govern the bioactivity of CHA.     

Fabrication and In Vitro Bioactivity of Poly (ϵ-caprolactone) Composites Filled with Silane-Modified Nano-Apatite Particles

Silane coupling agents were firstly employed to modify the surfaces of nano-apatite (n-HA) particles, and then thin films of the silanized n-HA/PCL composites were successfully developed by incorporating solvent dispersion and thermal co-blending with hot-pressing methods. In vitro studies were conducted using the 2-time simulated body fluid (2SBF). Composite specimens were soaked in 2SBF from 3 to 14. Results showed that a layer of bone-like apatite was formed within 7 days on the surfaces of all composites, after its immersion in 2SBF, demonstrating moderate in vitro bioactivity of these composites.     

生理模拟液中的磷酸钙微晶玻璃的表面变化

应用玻璃结晶法制备了以磷酸钙为主体的多孔微晶玻璃载体材料。在一定的条件下对该药物载体材料进行了生理模拟液的浸泡实验,并用Fourier红外光谱和扫描电镜对其表面进行了表征分析。试验结果表明：经模拟液浸泡后,在材料的表面沉积了一定量的类骨磷灰石(碳酸羟基磷灰石),其形貌为球状颗粒,并证实了载体材料的粗糙表面有利于碳酸羟基磷灰石晶体的形成。研究结果有助于分析碳酸羟基磷灰石的形成机理及了解磷酸钙微晶玻璃载体材料在体内的骨诱导机理。