TiO2/羟基磷灰石的结构及其光催化降解醛类的性能

 采用水热合成和离子交换法相结合制备了不同Ti/(Ti+Ca)摩尔配比的羟基磷灰石负载二氧化钛(TiO2/HAP)光催化剂. 用X射线衍射、拉曼光谱、红外光谱、紫外-可见漫反射光谱和微型连续光反应技术研究了催化剂的晶体结构、表面构造、光响应性能以及光催化降解甲醛和乙醛的性能. 结果表明, Ti/(Ti+Ca)配比是影响TiO2/HAP晶体结构、表面构造和光响应性能的重要因素, Ti/(Ti+Ca)摩尔比为 0.2时, TiO2/HAP为锐钛矿型TiO2和HAP的混合相, TiO2与HAP之间形成了 Ti-O-P 键,二者得到了有效的复合. 复合材料相对于TiO2在漫反射光谱吸光带边上有明显的红移,扩展了材料的吸光域. 在合适的条件下, TiO2/HAP光催化降解甲醛和乙醛的转化率分别达89.2%和82.7%, 矿化率达92.1%和75.2%.     

羟基磷灰石/丝素蛋白复合纤维的制备及其矿化研究

在以静电纺丝法制备羟基磷灰石(HAP)/丝素蛋白(SF)复合纤维的前提下, 采用同轴共纺法获得了以HAP为“芯”、SF为“皮”的双组分电纺纤维(电纺膜), 并通过扫描和透射电镜、红外光谱以及X射线衍射等手段对电纺纤维进行了表征. 结果表明, HAP均存在于上述两种方法制备的纳米纤维中, 但同轴共纺法不仅可以避免HAP/SF共混电纺时pH值对丝素蛋白结构的影响, 并且能大大提高电纺膜中HAP的含量. 同时, 我们还分别以SF纤维、HAP/SF复合纤维和HAP/SF“皮-芯”纤维作为有机基质, 对羟基磷灰石在其上的矿化过程进行了探索, 结果表明含较多羟基磷灰石的HAP/SF“皮-芯”纤维更有利于矿化的进行.     

Ru掺杂BiOBr空心微球的原位合成及其光催化CO_2还原和有机污染物降解性能研究

采用水热法原位合成了Ru掺杂BiOBr空心微球(Ru/BiOBr)复合光催化剂,并对其进行了XRD、 SEM、 TEM、 EDS、 DRS、 EIS等表征.结果表明,所合成的BiOBr材料是由许多小厚度的交错纳米片自组装而成的,同时Ru纳米颗粒成功负载到BiOBr表面,该复合材料对还原CO_2和降解有机模拟污染物(罗丹明B, RhB)具有良好的光催化性能.当Ru的掺杂量为0.4%时复合材料的光催化活性最佳, 4 h后甲醇产量可达1103μmol/g_(cat),并且60 min内对RhB的降解率达到98%.除此之外,还讨论了复合材料的光催化机理和稳定性.     

碳纳米管/壳聚糖复合微球的原位仿生矿化及表征

对碳纳米管(CNTs)进行酸化处理, 采用乳化交联法制备CNTs/壳聚糖(CS)复合微球, 在其表面诱导羟基磷灰石仿生合成, 研究了CNTs对复合微球仿生矿化的影响, 并与纯CS微球的仿生矿化进行了对比. 利用扫描电子显微镜(SEM)、 X射线衍射仪(XRD)、 溶胀率和含水率测试等考察了复合微球矿化前后的形貌特征、 物相结构及稳定性. 结果表明, 在相同时间下, CNTs/CS复合微球表面纳米羟基磷灰石的形成能力明显优于纯CS微球, 且形态稳定性更高. 细胞实验结果表明, 与MG63细胞共培养7 d时, 矿化复合微球细胞增殖明显.     

C_3N_4/BiVO_4/Cu_2O复合材料用于纯水中CO_2光还原为甲醇

采用分步合成方法将Cu_2O纳米颗粒原位还原组装到C_3N_4/BiVO_4表面,设计并合成了C_3N_4/BiVO_4/Cu_2O复合材料.在该过程中,首先将具有光氧化能力的BiVO_4与C_3N_4复合制备出C_3N_4/BiVO_4复合物,进一步通过原位合成法在C_3N_4/BiVO_4复合物表面沉积Cu_2O纳米颗粒制备出C_3N_4/BiVO_4/Cu_2O复合材料.通过高分辨透射电镜和高分辨扫描电镜,X射线粉末衍射,紫外-可见光谱及荧光光谱等测试方法对材料的结构、形貌与组成进行了系统的表征.在纯水体系中,光催化研究表明该复合材料具有较好的二氧化碳到甲醇的转化效率,复合材料的形成有利于促进光生电子和空穴的分离,从而提高光催化性能.     

含磷脂酰胆碱的聚乳酸的诱导矿化研究

分别以甘油磷脂酰胆碱和1,4-丁二醇为引发剂开环丙交酯,制备了含磷脂酰胆碱的聚乳酸(PLA-PC)和聚乳酸(PLA),比较了两者在诱导矿化中的差异.用傅立叶红外光谱仪(FTIR)、X-射线衍射仪(XRD)和扫描电子显微镜(SEM)对PLA-PC膜表面形成的矿化物进行了表征.结果表明,形成的矿化物为羟基磷灰石(HAP),PLA-PC膜有利于成核和生长,晶体呈片状,并随矿化时间延长,HAP晶粒逐渐增大,晶片厚度也逐渐变大.     

微纳复合结构MFe2O4负极材料的可控合成与性能

采用新溶剂热体系一步合成MFe₂O₄(M=Zn/Co)负极材料. 通过调控反应时间可分别制备出由一次纳米颗粒组装成的亚微米级空心和实心球形结构复合材料. 与实心球形微纳复合材料相比, 空心球形微纳复合材料具有结晶度高、 颗粒粒径大、 放电比容量高、 循环性能好及电化学阻抗低等优点. 空心球形ZnFe₂O₄和CoFe₂O₄样品充放电循环50周后分别保持655和1180 mA·h/g的比容量, 远高于实心球形ZnFe₂O₄和CoFe₂O₄材料的305和524 mA·h/g, 说明微纳复合铁酸盐材料的结构和组装形式对其电性能有较大影响.     

羟基磷灰石包覆γ-Fe2O3担载氧化钼:一种新型磁性可回收的烯烃环氧化多相催化剂

制备了羟基磷灰石(HAP)包覆纳米γ-Fe2O3颗粒复合材料(HAP-γ-Fe2O3),并进一步采用浸渍法担载氧化钼(MoOx/HAP-γ-Fe2O3).高分辨透射电镜结果表明,γ-Fe2O3纳米颗粒被包覆于HAP当中,平均粒径为1～3 nm.所制各催化剂对以叔丁基过氧化氢为氧化剂的烯烃环氧化反应显示了良好的催化活性,...     

聚乳酸骨固定材料的研究

用聚乙烯醇(PVA)的二甲基亚砜(DMSO)溶液对水热反应法合成的超细羟基磷灰石(HAP)进行表面改性,用溶液分散复合法分别制备了HAP含量均为0．03g／mE的聚乳酸(PLLA)／HAP和PLIA／HAP-PVA复合物,并经过挤出成型得到φ=5mm的棒材。重点研究了热拉伸取向的拉伸规律及表面改性前后HAP粒子在PLLA基质中的分散情况。结果表明,经PVA改性的HAP粒子在PLLA基质中的分散要明显优于未经改性的HAP粒子。拉伸取向后PLLA／HAP-PVA复合材料的弯曲强度达262MPa。     

纳米CdSe与聚4-乙烯基吡啶盐的复合与表征

用巯基乙酸作稳定剂在水相中合成了CdSe纳米颗粒. 聚4-乙烯基吡啶季铵盐(PVPNI)通过静电作用与CdSe纳米颗粒复合形成了纳米复合材料.该复合材料通过红外光谱数据（IR）、电感耦合等离子发射光谱（ICP-AES）、透射电镜（TEM）等方法进行了表征,并通过紫外可见吸收光谱(UV-Vis)和荧光光谱(PL)对其光学性质进行了研究.结果表明,复合材料的形成,改善了纳米CdSe的分散性,并提高了纳米CdSe的荧光强度.     

Comparative study of particle size analysis of hydroxyapatite-based nanomaterials

The purpose of this work was to compare hydroxyapatite (HAP) and composites of HAP, HAP with chitosan (CS), and HAP with poly(vinyl pyrrolidone) (PVP), in terms of their particle size and morphology, using different methods, such as Coulter counter analysis, X-ray diffraction (XRD), and transmission electron microscopy (TEM). Although many researchers have studied HAP and CS/HAP and PVP/HAP composites extensively, there is no evidence of a comparative study of their particle sizes. For this reason, different complementary methods have been used so as to provide a more complete image of final product properties — particle size — from the perspective of possible applications. The syntheses of HAP and HAP with polymer nanoparticles were carried out employing a precipitation method. Variation in particle size with synthesis time and influence of the reactants’ concentration on the materials’ preparation were systematically explored. Crystallite size calculated from XRD data revealed nanosized particles of HAP, CS/HAP, and PVP/HAP materials in the range of 2.5–9.2 nm. Coulter counter analysis revealed mean particle sizes of one thousand orders of magnitude larger, confirming that this technique measures agglomerates, not individual particles. In addition, the particles’ morphology and an assessment of their binding mode were completed by TEM measurements.     

HAP自组装球的简易合成及其光催化增效作用

选择生物协同模板,通过简单的控制组装工艺,制备出结构均一有序的羟基磷灰石(HAP)纳米组装球.该纳米组装球整体尺寸约5-6 μm,球体中心部分尺寸约为2.5-3 μm.通过X射线粉末衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、傅里叶变换红外(FT-IR)光谱、比表面积(BET)测试等手段对产物形貌、结构和比表面积进行了表征.产物作为催化剂载体,对氧化锌催化降解罗丹明B (RhB)的催化效率提高了125%,催化剂回收率提高了23.1%,有效降低了催化剂的用量,在有机物降解领域具有潜在的应用价值.同时还对产物的控制生成过程和催化增效机理做了初步探讨.     

溶胶-凝胶法制备Ca10(PO4)6(OH)2 /TiO2复合涂层及其在模拟生理体液中的行为

The composite films consisting of hydroxyapatite (HAP) submicron particles embedded in the gel composed of the titania nanoparticles were prepared on commercial Ti6A14V plates with titania buffer layer obtained by a spin-coating technique. The films were calcined in air at various temperatures, and the bioactivities of the films were investigated by immersing them in acellular simulated body fliud (SBF). X-ray diffraction(XRD), Fourier transform infrared spectroscopy (FTIR), Field emission-scanning electron microscopy(FESEM) and Energy dispersive X-ray (EDS) analysis were employed to investigate the phase formation and structure of the films before and after immersion, and the variations of Ca and P contents in SBF were measured by Inductively Coupled Plasma Spectroscopy(ICP). The results show that the as-prepared films were dense, homogeneous, all well-crystallized, and there was a close interracial bond between the film and the substrate. The characterisatics of the grown layer on the surfaces of the HAP/TiO2 films after immersion in SBF for different periods of time are specially discussed.     

苯乙烯和N-乙烯基吡咯烷酮共聚物/Ag复合微球的制备及性能研究

首先用无皂乳液聚合法制备了单分散聚苯乙烯(PSt)乳液,以此为种子乳液,使用N,N-亚甲基双丙烯酰胺(MBA)为交联剂,过硫酸钾(KPS)为引发剂,进行苯乙烯和N-乙烯基吡咯烷酮(NVP)共聚合制备了以PSt为核、St和NVP共聚物为壳的具有核-壳结构的聚合物微球(P(St-NVP)).以此微球为模板通过化学沉积法得到了粒径分布均匀、单分散的P(St-NVP)/Ag复合微球.傅里叶红外光谱、X-射线衍射、扫描电镜、透射电镜、激光粒度仪和紫外-可见光谱对复合微球的结构、形貌、物相及催化性能进行了表征.结果表明,P(St-NVP)/Ag复合微球具有规则的球形结构,粒径在400～700 nm之间,随交联剂浓度或种子乳液浓度的增加,复合微球粒径减小.粒径在十几个纳米左右的银粒子均匀分布在微球表面和内部.载银复合微球在NaBH4还原4-硝基苯酚为4-氨基苯酚的模型反应中表现出较高的催化活性.     

聚肽-壳聚糖复合体系的自组装行为研究

以聚肽、壳聚糖为原料,制备复合纳米粒子,采用透射电镜、动态激光散射仪及Zeta电位分析仪、荧光光谱仪对制备成的聚肽-壳聚糖复合体系纳米粒子的形貌、粒径、Zeta电位及临界胶束浓度等自组装行为进行表征,结果表明:聚肽-壳聚糖复合体系纳米粒子是具有壳-核结构的球型粒子;纳米粒子平均粒径为240nm,粒径分布较均匀,稳定性较好;复合体系中聚肽的临界胶束浓度为4.55×10-4mg/mL.     

Roles of amorphous calcium phosphate and biological additives in the assembly of hydroxyapatite nanoparticles

Potential mechanisms for formation of highly organized biomineralized structures include oriented crystal growth on templates, the aggregation of nanocrystals by oriented attachment, and the assembly of inorganic nanoparticles mediated by organic molecules into aggregated structures. In the present study, the potential role of amorphous calcium phosphate (ACP) in facilitating the assembly of hydroxyapatite (HAP) nanoparticles into highly ordered structures was evaluated. The physical characteristics of HAP nanoparticles prepared by three different methods were analyzed after extended exposure to additives in solution. Higher order HAP architecture was detected only when the starting particles were aggregates of nanospheres with HAP cores and ACP shells. Enamel-like HAP architecture was produced when the biologic additive was 10 mM glycine or 1.25 microM amelogenin. Large platelike crystals of the type present in bone were induced when the additive was 10 mM glutamic acid. Surface ACP initially links the HAP nanoparticles in a way that allows parallel orientation of the HAP nanoparticles and then is incorporated into HAP by phase transformation to produce a more highly ordered architecture with features that are characteristic for HAP in biologic structures. These studies provide evidence for a new mechanism for assembly of biominerals in which ACP functions by linking HAP nanocrystals while they assume parallel orientations and then is incorporated by phase transformation into HAP molecules that rigidly link HAP nanocrystals in larger fused crystallites. Biologic molecules present during this process of biomineral assembly specifically regulate the assembly kinetics and determine the structural characteristics of the final HAP architecture.     

阴离子氨基酸表面活性剂调控下水热合成羟基磷灰石纳米片

利用水热合成方法, 在含有氨基酸结构的阴离子表面活性剂N-酰基十二烷基肌氨酸钠(Sar-Na)的控制下, 合成具有较大长径比(aspect ratio)的片状纳米羟基磷灰石晶体. 采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)和傅立叶变换红外(FTIR)光谱表征, 并分析了合成产物的形貌、结构和组成. 结果表明, 在Sar-Na的调控下合成了长度0.5-1.0 μm、宽约30 nm的片状羟基磷灰石晶体, 其长径比约为20:1. 考察了表面活性剂Sar-Na的用量对羟基磷灰石形貌的影响. 随着Sar-Na的添加及用量的增加, 羟基磷灰石由椭圆形变为长片状, 并且片的两端逐渐变尖. 结果显示了Sar-Na对羟基磷灰石形貌的控制作用, 为合成具有较大长径比的羟基磷灰石纳米片提供了一个新的途径.     

Preparation of poly(methyl methacrylate) grafted hydroxyapatite nanoparticles via reverse ATRP

Surface-initiated reverse atom transfer radical polymerization (reverse ATRP) technical was successfully employed to modify hydroxyapatite (HAP) nanoparticles with poly(methyl methacrylate) (PMMA). The peroxide initiator moiety for reverse ATRP was covalently attached to the HAP surface through the surface hydroxyl groups. Reverse ATRP of methyl methacrylate (MMA) from the initiator-functionalized HAP was carried out, and the end bromide groups of grafted PMMA initiated ATRP of MMA subsequently. Fourier transformation infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA) and transmission electron microscopy (TEM) were employed to confirm the grafting and to characterize the nanoparticle structure. The grafted PMMA gave HAP nanoparticles excellent dispersibility in MMA monomer. As the amount of grafted PMMA increased, the dispersibility of surface-grafted HAP and the compressive strength of HAP/PMMA composites were improved.     

SiO2 /Au核壳结构纳米粒子的制备及表征

通过以金纳米粒子为表面晶种和壳生长的方法制备了金纳米壳包覆二氧化硅的复合纳米粒子。采用TEM 和UV-Vis对复合粒子进行了表征和研究，结果表明所得到的复合粒子粒径均匀、金纳米壳光滑完整，且壳厚度可通过反应物的用量来控制。当核半径与壳厚度之比在4到13之间变化时,复合粒子的光学共振峰在可见光区到近红外光区范围内可发生大于500 nm波长的移动。     

PET/SiO2 nanocomposites prepared by cryomilling

The mixed powders of poly(ethylene terephthalate) (PET) and SiO₂ has been subjected to cryomilling. The evolution of microstructure with time was characterized using scanning electron microscope, transmission electron microscope, field emission scanning electron microscope, and laser diffraction particle size analyzer. It was shown that, upon cryomilling for 10 h, SiO₂ nano particles were well deconglomerated into single particles (～30 nm) that get homogeneously dispersed in PET matrix. The resulted PET/SiO₂ primary particles were flake‐shaped with a size of 400 nm. These primary composite particles agglomerated to form secondary composite particles with an average size about 7.6 μm. A three‐stage model was purposed for the formation mechanism of the nanocomposite structures induced by cryomilling. Our evidences suggest that cryomilling is a capable and promising technique for the production of polymer/inorganic nanocomposites. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1161–1167, 2006