Ag–Sr doped mesoporous bioactive glass nanoparticles loaded chitosan/gelatin coating for orthopedic implants

In this study, we investigated surface and biological properties of Ag–Sr-doped mesoporous bioactive glass nanoparticle (Ag–Sr MBGN) loaded chitosan/gelatin coatings deposited by electrophoretic deposition (EPD) on 316L stainless steel. The EPD parameters, that is, deposition time, applied voltage, and distance between the electrodes was optimized by the Taguchi design of experiment (DoE) approach. Scanning electron microscopy (SEM) images illustrated the spherical morphology of the synthesized Ag–Sr MBGNs with the mean particle size of 160 ± 20 nm. Energy-dispersive X-ray (EDX) spectroscopy results confirmed the presence of Ag and Sr in the synthesized MBGNs. Optimum EPD parameters determined by DoE approach were 5 g/L of Ag–Sr MBGNs, deposition time of 5 min, and applied voltage of 30 V. SEM images confirmed that the coatings were fairly homogenous. Fourier-transform infrared spectroscopy and EDX results confirmed the presence of chitosan, gelatin, and Ag–Sr MBGNs in the coatings. Chitosan/gelatin/Ag–Sr MBGN composite coatings exhibited suitable wettability for the protein attachment and proliferation of osteoblast cells. The composite coatings exhibited suitable adhesion strength with the substrate. The coatings developed HA crystals upon immersion in simulated body fluid. The results of the turbidity test confirmed that the coatings are antibacterial to the Escherichia coli cells.     

Optimization of Parameters for Synthesis of MFI Nanoparticles by Taguchi Robust Design

MFI‐type zeolite was successfully synthesized by hydrothermal crystallization of clear synthesis mixtures. A statistical experimental design method (the Taguchi method with an L8 orthogonal array) was implemented to optimize the experimental conditions for the preparation of MFI nanocrystals with respect to particle size and distribution as the desirable properties. In the Taguchi experimental design, crystallization temperature, water content, template/silica molar ratio, aluminum content, as well as the presence of alkaline cations were chosen as significant parameters affecting the properties. It was shown that water and aluminum content of the synthesis solution were the most important parameters affecting particle size and distribution. The MFI nanocrystals with an average particle size of 95 nm and the narrow particle size distribution of ± 8.5 nm were synthesized under optimum conditions.     

The preparation and characterization of NaWO3 particles for heat shielding by Taguchi optimization method

The synthesis of sodium tungsten oxides (NaWO₃) particles was accomplished to apply on the heat shielding film. In this preparation, Taguchi method with L₉ orthogonal array was used to optimize experimental conditions for the formation of NaWO₃ particles. Primary mean particle size and the standard deviation of NaWO₃ particles were considered as the characteristics. Concentration of sodium tungstate (Na₂WO₄), concentration of sodium borohydride (NaBH₄), and pH value were selected as main parameters. As the result of Taguchi analysis in this work, the concentration of sodium tungstate was the most influencing parameter on the particle size and the standard deviation. The pH value had also principal effect on particle size and size distribution. The optimal conditions were determined by using Taguchi optimization design method and NaWO₃ particles with primary mean size (∼100 nm) were prepared. By the analyses of X-ray diffraction and UV–vis spectrum, it was found that the annealed NaWO₃ particles were more effective on heat shielding than non-annealed particles.     

Application of the Taguchi Method in Analyzing the Impact of Modified Gemini Surfactants on TiO2 Nano-Suspension

Regarding the TiO₂ nano-suspension under different influencing parameters such as hydrophilic chain length of the modified gemini surfactant (dispersant), electrolyte concentration and dispersant concentration, this study applied the Taguchi Method to analyze the optimal parameters of the TiO₂ nano-suspension using an L9(3³) orthogonal array for making the experimental formulas with the average particle size of the suspension as the smaller-the-better indicator. The experimental results suggested that the dispersing particle size of the nano-suspension was affected in order by the dispersant concentration (64.11%), the hydrophilic group chain length of dispersant (11.16%) and the electrolyte concentration (3.04%). Then, by the confirmation experiments based on the optimal parameter combinations of Taguchi Method analysis, the TiO₂ nano-suspension of uniform and minimized particle size were obtained. The result was within the 95% confidence interval, indicating that the reproducibility of the parameter design was high.     

Multi‐Parameter Study of Nanoscale TiO2 and CeO2 Additives in Composite AP/HTPB Solid Propellants

A statistical Taguchi L8 matrix was used to conduct a multi‐parameter study of the use of nanoscale additives in composite solid propellants. The additives studied were TiO₂ (titania) and CeO₂ (ceria). The other parameters involved in the experiment were the oxidizer loading and distribution, additive percentage and size, additive size (nano‐scale or μm‐scale), and the mixing method. Four baseline propellants without additives were also produced for comparison. The propellants were tested from 3.45 to 13.78 MPa in a strand bomb, and burning rate curves were determined for all formulas. By analyzing the Taguchi matrix, the sensitivity of each parameter according to the pressure sensitivity and burning rate of the propellant was calculated. The dominant factors depend on whether the additive is needed for modifying the pressure index or the absolute value of the burning rate. In general, the effectiveness of the additives was most influenced by oxidizer percentage, oxidizer size distribution, and additive type. The amount of additive, mixing method, and additive size all had relatively minor impacts on the effectiveness of the additives.     

紫外光辐照下以PAMAM树形分子为模板制备Ag纳米簇及光致发光性能研究

以G5．0-OHPAMAM树形分子为模板，用紫外光辐照法制备银纳米簇．用透射电子显微镜、紫外-可见吸收光谱和共振散射光谱等对所制备的银纳米簇进行了表征．结果表明：用紫外光辐照法可以制备尺寸分布均匀、稳定的银纳米簇；且辐照时间、PAMAM树形分子的浓度及Ag^＋／PAMAM树形分子的摩尔比都会对所制备的银纳米簇产生较大的影响．由于所制备的银纳米簇的粒径小于树形分子的流体力学半径，表明树形分子起到了“内模板”作用．同时研究了银纳米簇的尺寸对其光致发光性能的影响，发现通过调节银纳米簇的尺寸可实现其光致发光的可调性．     

保压工艺和浇口尺寸对非球面镜头收缩性能的影响

以非球面光学塑料镜头为研究对象,结合田口实验设计方法对其进行模拟实验,通过对实验数据进行信噪比和方差分析,研究了浇口尺寸、保压压力、保压时间及其三者之间的交互作用对产品体积收缩性能的影响。结果表明,影响非球面镜头收缩性能的因素从大到小依次为:保压压力、浇口尺寸和保压时间;同时研究表明保压压力和浇口尺寸之间的交互作用也是影响产品收缩性能的重要因素之一。最后基于研究所得的最优工艺方案组合,达到了降低了产品体积收缩、提升产品合格率的目的。     

Taguchi‐based analysis of polyamide 6/acrylonitrile–butadiene rubber/nanoclay nanocomposites: The role of processing variables

Applying the Taguchi method of experimental design, we prepared various polyamide 6 (PA6)/acrylonitrile butadiene rubber (NBR)/nanoclay nanocomposites under different processing conditions by melt mixing in an internal mixer. The effects of the processing variables, including the rotor speed, chamber temperature, and mixing order on the morphology, that is, the rubber particle size and interlayer distance, and the mechanical properties, that is, the tensile modulus and impact strength, were then investigated. As demonstrated with the Taguchi approach, the lower temperature associated with higher rotor speeds improved the mechanical properties of the 90/5/5 PA6/NBR/nanoclay systems. However, it was revealed that the mixing order did not affect the mechanical properties for the assigned composition. Hence, the simultaneous mixing of all the ingredients is seemingly the simplest way of mixing to obtain the desired mechanical properties. These results were confirmed with transmission and scanning electron microscopy observations and X‐ray diffraction measurements. Image analysis corresponding to the mean particle size of the NBR constituent was also performed. The optimum processing condition to achieve the appropriate mechanical properties is ultimately predicted by the Taguchi analysis and corresponded to a chamber temperature of 230°C and a screw speed of 80 rpm. Moreover, the simultaneous mixing of all of the ingredients was suggested for convenience. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 820‐828, 2013     

Continuous-Wave Laser Patterning of Three-Dimensional Microstructure in Glasses Containing Silver Nanoparticles

A method is reported that uses visible continuous-wave laser to directly fabricate micropatterns in glasses containing silver (Ag) nanoparticles. Ag nanoparticles were formed in the glass using thermal treatment. Upon laser irradiation, Ag nanoparticles with their surface plasmon in resonance with the laser beam were partially melted and decreased in size due to the temperature increase induced by the excited Ag nanoparticles. Three-dimensional patterns were achieved by scanning the laser beam through the thickness of the glass.     

P(St-AM)@Ag复合微球的气敏性研究

通过在核壳聚合物聚(苯乙烯-丙烯酰胺)微球表面吸附Ag+继而用紫外灯光照还原,制备了P(St-AM)@Ag复合微球。采用扫描电子显微镜、紫外可见反射光谱、X-射线粉末衍射对P(St-AM)@Ag复合微球进行了表征,并研究了复合微球的气敏性。结果表明,所制备P(St-AM)@Ag复合微球对乙醚蒸气具有良好的响应性和响应稳定性,复合微球粒径越小、微球表面包覆的Ag越多,响应性越大,粒径205nm的P(St-AM)@Ag复合微球在饱和乙醚蒸气中的最大响应性可达3.12。     

Physico-Chemical Effects on the Scale-Up of Ag Photodeposition on TiO2 Nanoparticles

We have previously demonstrated that TiO₂ nanoparticles can be functionalized by photodeposition with silver or gold particles in the 1?C2 nm range presumed to be desirable for catalysis applications. However, the preparation of these samples directly on microscope grids, while conducive to particle size determinations, did not produce sufficient materials for reaction studies. We report here scale-up techniques designed to produce greater quantities of material for testing, while maintaining characteristics that contribute to uniformity in the deposition process. For the scale-up process, an irradiation source with highly uniform intensity is necessary to generate Ag/TiO₂ samples with consistent Ag loading. In addition, control of the precursor concentration is also required to produce Ag/TiO₂ samples with high Ag loading and narrow Ag size distribution. The optimum conditions for the scale-up process found in this study involved Ag photodeposition from a 5 × 10^?3 M AgNO₃ solution using a high pressure Hg lamp at 366 nm for 60 s. Under these reaction conditions, the size of Ag particles determined by TEM and HAADF-STEM imaging was within 1?C2 nm and the Ag loading was ~3.2 wt%. Achievement of this level of uniformity required control of the uniformity of illumination, as well as of the solution concentration and irradiation conditions. Higher solution concentrations and higher power led to the growth of larger (ca. 10 nm) silver particles. In contrast, the loading and size distribution of the Ag particles photodeposited were remarkably insensitive to the source and morphology of the TiO₂ nanoparticles utilized. No Ag peak was resolved in the XRD patterns for Ag/TiO₂ samples obtained from the optimized scale-up process, corroborating the size range determination of the Ag nanoparticles. XPS showed that the Ag particles in all cases were metallic Ag.     

吸附相反应技术制备纳米Zno/SiO2

采用吸附相反应技术制备ZnO/SiO2纳米复合材料,考察了反应途径、体系中水含量和NaOH浓度对ZnO/SiO2纳米复合材料的影响,并采用透射电子显微镜(TEM)、X-射线衍射(XRD)、酸碱滴定和络合滴定等手段对ZnO/SiO2纳米复合材料进行了表征.结果表明,利用吸附相反应技术能有效调控ZnO粒子粒径,吸附质种类与浓度以及吸附层厚度与性质均会影响粒子的粒径.随着吸附层厚度的增大,粒径逐渐增大;随着物理吸附层的形成以及吸附质浓度增高,粒径逐渐变小.与Ag纳米粒子制备过程对比,发现制备Ag和ZnO粒子的反应机理不同导致两种粒子的形成和生长过程有较大差异.     

银纳米颗粒负载TiO2复合薄膜的光催化活性及其光电流性质

制备了3种不同粒径的Ag纳米颗粒，将它们分别掺入二氧化钛溶胶，制备成复合二氧化钛薄膜，利用TEM测定了Ag粒子的大小，测量TiO2复合膜的光电流，以亚甲基蓝降解反应评价了Ag／TiO2薄膜的光催化活性，结果表明，负载不同粒径Ag纳米粒子后，TiO2薄膜的光电流和光催化活性均得到一定程度的提高。当负载平均粒径6.9nm的Ag粒子后，薄膜具有最高的光电流和最强的光催化活性。     

苯乙烯/丙烯酸共聚高分子微球的制备与研究

以苯乙烯为主单体,丙烯酸为亲水性功能单体,采用无皂乳液聚合方法制备了苯乙烯/丙烯酸共聚微球,并在微球表面沉积金属Ag纳米粒子。讨论了引发剂用量、功能单体丙烯酸的加入方式以及用量对微球粒径和形态的影响,并研究了金属Ag纳米粒子的沉积过程。通过透射电镜观察发现,微球形态规整,粒径分布均匀。金属Ag纳米粒子较均匀的沉积在微球表面。     

微细发泡注塑成型工艺与微泡尺寸的关系

以数值模拟作为实验手段,工艺参数对微泡长大的影响的判断则采用田口实验方法来进行;结果得出各工艺参数对微泡尺寸的影响次序由大到小为：熔体温度、初始填充量、注射时间、模具温度。在此基础上,进一步研究了各个工艺参数对微泡长大的影响,得出适当降低熔体温度和提高初始填充量可以优化微细发泡注塑制品的微泡尺寸;而注塑时间和模具温度对微泡尺寸的影响不大。     

Synthesis and intercalation of silver nanoparticles in kaolinite/DMSO complexes

Ag nanoparticles were synthesized in the interlamellar space of a layered kaolinite. Disaggregation of the lamellae of the nonswelling kaolinite was achieved by the intercalation of dimethyl sulfoxide (DMSO). The kaolinite was suspended in aqueous AgNO₃ solution and the adsorbed Ag⁺ ions were reduced on the surface of kaolinite lamellae with NaBH₄ or UV light irradiation. The silver nanoparticles formed were characterized by X-ray diffraction (XRD), small angle X-ray scattering (SAXS), and transmission electron microscopy (TEM). We studied the effects of the two reduction methods on the size and the size distribution of Ag nanoparticles and how clay mineral structure is altered as a consequence of particle formation. It was established that the size of Ag nanoparticles depends on both silver content and the reduction method. Photoreduction of silver led to the formation of relatively large Ag nanoparticles (diameter 8–14 nm).     

航空煤油在不同孔径的Ag基介孔材料吸附剂上深度吸附脱硫的研究

以3种不同孔径的介孔材料MCM-41,SBA-15,大孔SBA-15(SBA-15-L)为载体,采用离子交换法制备了Ag/Al-MCM-41,Ag/Al-SBA-15和Ag/Al-SBA-15-L介孔材料吸附剂。利用XRD,N2吸附,SEM-EDS,ICP-MS等手段对所制备的吸附剂进行了表征,并在固定床上对航空煤油进行了吸附脱硫研究。结果表明,交换Ag+所制备的吸附剂依然保持介孔材料的特性,并可将含S量为150×10-6的航空煤油中的硫化物,选择性的吸附脱除到S含量低于1.0×10-6。其中,在Ag/Al-MCM-41,Ag/Al-SBA-15和Ag/Al-SBA-15-L吸附剂上,可分别得到8.0,9.0和17.0mL的清洁航空煤油(含硫量小于1.0×10-6)。实验结果也表明,所制备的吸附剂吸附脱硫性能主要取决于介孔材料载体的孔径大小,载体的孔径越大,Ag+的利用率越高,吸附剂的吸附脱硫性能越强。将吸附饱和的Ag/Al-SBA-15-L吸附剂,于空气中在350℃进行再生5h,吸附剂的吸附性能可以100%的恢复。     

Influence of laser parameters in surface texturing of polyphenylene sulfide composites

Creating dimples at the ideal geometries to enhance the tribological properties of the polyphenylene sulfide (PPS) composite surface is the principal purpose of this study. In this manner, the effects of focus position (FP), pulse number (PN), and energy used for the making dimple geometry were investigated. In the ablation process, Nd:YAG laser with 1064 nm wavelength was used. Optimum laser process parameters were intended to obtain the largest ratio of dimple depth to width, circular dimples with a minimum ratio of molten zone diameter to spot size. The most effective parameters for obtaining dimple of desired properties are pulse energy (PE) with 60.64%, pulse duration (PD) with 55.61%, and FP with 55.94% for aspect ratio, circularity, and ratio of the diameter of the dimple to the spot size, respectively. In order to achieve a high aspect ratio or good circularity or minimum molten zone-to-spot size ratio, Taguchi optimization predicted the laser parameters. In the confirmation experiment with the proposed parameters, the highest aspect ratio was obtained as 2.05, the best circularity was obtained as 1.05, and minimum molten zone-to-spot size ratio was obtained as 1.073. Using the Taguchi method, accurate results were found with less experimentation. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47976.     

Characterization and Antimicrobial Property of Poly(Acrylic Acid) Nanogel Containing Silver Particle Prepared by Electron Beam

In this study, we developed a one step process to synthesize nanogel containing silver nanoparticles involving electron beam irradiation. Water-soluble silver nitrate powder is dissolved in the distilled water and then poly(acrylic acid) (PAAc) and hexane are put into this silver nitrate solution. These samples are irradiated by an electron beam to make the PAAc nanogels containing silver nanoparticles (Ag/PAAc nanogels). The nanoparticles were characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). In addition, the particle size and zeta-potential were confirmed by a particle size analyzer (PSA). The antibacterial properties of the nanogels were evaluated by paper diffusion test. The Ag/PAAc nanogels had an antibacterial effect against Escherichia coli and Staphylococcus aureus. The nanogels also demonstrated a good healing effect against diabetic ulcer. The size of the Ag/PAAc nanogels decreased with increasing irradiation doses, and the absolute value of the zeta potential increased with increasing irradiation doses. Also, the Ag/PAAc nanogels exhibited good antibacterial activity against both Gram-negative and Gram-positive bacteria. In in vivo wound healing, the Ag/PAAc nanogels have a good healing effect.     

Thermal decomposition as route for silver nanoparticles

Single crystalline silver nanoparticles have been synthesized by thermal decomposition of silver oxalate in water and in ethylene glycol. Polyvinyl alcohol (PVA) was employed as a capping agent. The particles were spherical in shape with size below 10 nm. The chemical reduction of silver oxalate by PVA was also observed. Increase of the polymer concentration led to a decrease in the size of Ag particles. Ag nanoparticle was not formed in the absence of PVA. Antibacterial activity of the Ag colloid was studied by disc diffusion method.