共查询到19条相似文献,搜索用时 140 毫秒
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为了改善无机粒子在聚合物基体中的分散性与相容性.采用2种表面处理方法:硅烷偶联剂KH570表面处理Al2O3粒子得到烷基化粒子;另外在此基础上采用溶液聚合法在烷基化Al2O3粒子表面进行MMA与单体的接枝聚合,制备PMMA包覆Al2O3复合粒子.Al2O3-g-PMMA。采用XPS、IR研究烷基化粒子与复合粒子表面结构.同时通过无机粒子直接填充法与PP基体复合获得Al2O3/PP复合材料并研究其力学性能与结晶行为。 相似文献
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利用苯乙烯-甲基丙烯酸共聚物对疏水性的Mn掺杂的ZnS量子点(ZnS:Mn QDs)进行包覆,得到了发光效率更好的水溶性量子点复合物(QDs-NIP)。用紫外分光光度计(UV-vis),荧光分光光度计(PL)和红外分光光度计(FTIR)对其进行结构及光学的表征。结果发现,红外光谱图证明我们成功合成了量子点、共聚物的复合纳米粒子,且其水溶后的复合纳米粒子仍能拥有高的发光效率;我们得到的高发光效率,水溶性好的ZnS:Mn QDs为后续的细胞成像,生物传感,细胞标记等打下了好的基础。 相似文献
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为了改善无机粒子在聚合物基体中的分散性与相容性 ,采用 2种表面处理方法 :硅烷偶联剂KH5 70表面处理Al2 O3粒子得到烷基化粒子 ;另外在此基础上采用溶液聚合法在烷基化Al2 O3粒子表面进行MMA与单体的接枝聚合 ,制备PMMA包覆Al2 O3复合粒子Al2 O3-g -PMMA。采用XPS、IR研究烷基化粒子与复合粒子表面结构 ,同时通过无机粒子直接填充法与PP基体复合获得Al2O3/PP复合材料并研究其力学性能与结晶行为 相似文献
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纳米氧化锌表面包覆氧化铝复合粉体制备及其光催化活性 总被引:14,自引:0,他引:14
在制备ZnO的前驱物 ? 碱式碳酸锌的过程中原位包覆Al2O3,与在ZnO粉体表面包覆的传统工艺相比减少了多次引起粒子团聚的工艺过程,改善了包覆效果. TEM观察表明,包覆的ZnO复合粉体粒径为50 nm左右、包覆层厚为3~5 nm. XPS分析表明,包覆层为Al2O3和ZnO. 光催化活性的测试表明,包覆后的纳米ZnO光催化活性得到了明显降低. 包覆后的纳米ZnO紫外线吸收性能与未包覆的纳米ZnO基本相同,保证了其优异的紫外吸收性能. 相似文献
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为防止铝粉在存储中氧化失活,同时为含铝炸药配方设计提供借鉴,采用聚叠氮缩水甘油醚(GAP)对不同尺寸Al粉(平均粒径分别为50nm和1~2μm)进行包覆改性,获得Al@GAP复合粒子;采用扫描电镜(SEM)、透射电镜(TEM)表征其形貌;用差示扫描量热法(DSC)对不同质量比的(Al@GAP)/LLM-105混合体系的热分解过程进行了研究。结果表明,采用两步包覆法获得了不同尺寸Al粉表面包覆GAP的核壳结构复合粒子;相较于包覆前的微米级Al粉,加入GAP包覆的纳米Al粉后混合体系的热分解峰温明显降低;当Al粉质量分数大于10%时,GAP包覆后的(Al@GAP)/LLM-105混合体系的熵变(ΔS~≠)和焓变(ΔH~≠)较Al/LLM-105混合体系有所减小;(Al@GAP)/LLM-105混合体系的活化能、热爆炸临界温度及热力学参数ΔS~≠和ΔH~≠随纳米Al粉含量的增加而降低,当Al粉质量分数为30%时,较LLM-105分别降低4kJ/mol、3℃、4.3J/(mol·K)、4.2kJ/mol。 相似文献
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Sung-Woo Choi Seong-Hyeon Hong Ki-Young Ko Young Rag Do 《Journal of the American Ceramic Society》2008,91(2):451-455
Blue-emitting ZnS:Ag phosphors were coated with nanoscale zinc oxide (ZnO) and Al-doped ZnO (AZO) and the cathodoluminescence (CL) performance of the coated phosphors was investigated. The nanoscale coating was obtained by controlling the hydrolysis reaction of ZnCl2 alcoholic solution using diethylamine as a gradual OH− former, and Al doping was performed to increase the electrical conductivity of ZnO. The coatings were composed of either nanosized particles or a continuous nano layer, and the AZO-coated phosphor had a more uniformly covered surface. The coated phosphors exhibited improved aging behavior under CL excitation and the AZO coating was more effective at suppressing the degradation, possibly due to its uniformity and high conductivity. 相似文献
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Donald S. Farquhar Rishi Raj S. Leigh Phoenix 《Journal of the American Ceramic Society》1990,73(10):3074-3080
Diamond particles have been embedded in hot-pressed zinc sulfide (ZnS) ceramic to improve various mechanical properties while preserving special optical properties. Roomtemperature mechanical tests on small specimens have shown that adding 10 wt% diamond to ZnS has no effect on the yield stress, but increases the tensile strength and the elastic moduli ∼20%, and increases the fracture toughness ∼100%. The doubling in fracture toughness can be explained by elastic interaction of the diamond particles with the crack-tip stress field. The results and the interpretation presented here are believed to represent a class of composite materials where both constituents are brittle but the dispersed phase has a much higher elastic modulus than the matrix. 相似文献
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Mn-doped ZnS nanocrystals based on low dopant concentrations (0–2%) and coated with a shell of Zn(OH)2 have been prepared via soft template and precipitation reaction. The results indicate that the ZnS:Mn nanocrystal is cubic zinc blende structure and its diameter is 3.02 nm as demonstrated by XRD. Measured by TEM, the morphology of nanocrystals is a spherical shape, and their particle size (3–5 nm) is similar to that of XRD results. Photoluminescence spectra under ultraviolet region shows that the volume ratio of alcohol to water in the template has a great effect on the luminescence properties of ZnS:Mn particles. Compared with unpassivated ZnS:Mn nanocrystals, ZnS:Mn/Zn(OH)2 core/shell nanocrystal exhibits much improved luminescence and higher absolute quantum efficiency. Meanwhile, we simply explore the formation mechanism of ZnS:Mn nanocrystals in alcohol and water system and analyze the reason why alcohol and water cluster structures can affect the luminescent properties of nanoparticle. 相似文献
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《Journal of the European Ceramic Society》2017,37(15):4741-4749
In the present study, zinc sulfide (ZnS) and calcium lanthanum sulfide (CaLa2S4, CLS) composite ceramics were consolidated via field-assisted sintering of 0.5ZnS-0.5CLS (volume ratio) composite powders at 800–1050 °C. Through sintering curve analyses and microstructural observations, it was determined that between 800 and 1000 °C, grain boundary diffusion was the main mechanism controlling grain growth for both the ZnS and CLS phases within the composite ceramics. The consolidated composite ceramics were determined to be composed of sphalerite ZnS, wurtzite ZnS and thorium phosphate CLS. The sphalerite-wurtzite phase transition of ZnS was further demonstrated to be accompanied by the formation of stacking faults and twins in the ceramics. It was also found that the addition of the CLS phase improved the indentation hardness of the ceramics relative to pure ZnS by homogeneous dispersion of ZnS and CLS small grains. 相似文献
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Mahdi Hajimazdarani Nima Naderi Benyamin Yarmand Alireza Kolahi Parvaneh Sangpour 《Ceramics International》2018,44(15):17878-17884
In this research, fabrication and characterization of ultraviolet (UV) detectors based on zinc sulfide–reduced graphene oxide (rGO) nanocomposite with the focus on the wurtzite structure of zinc sulfide was carried out. The nanoparticles of ZnS were synthesized using chemical deposition method and annealed at 500?°C under flow of argon. X-ray diffraction pattern showed that ZnS with the wurtzite phase was formed at 500?°C. Here, rGO as a unique material with similar properties to graphene such as high electron transport was used in order to improve the optical properties of ZnS. For this purpose, rGO was added to ZnS with three different weight percentages of 5, 10 and 15. Scanning electron microscopy showed that ZnS nanoparticles were well placed in rGO sheets. The UV–visible spectra of the synthesized composites showed that with increasing rGO in composite, light absorption is increased. Photoluminescence (PL) spectra also showed that with increasing the percentage of rGO the generation of electron-hole in composite was increased and PL peak was enhanced. The effect of elevated generation of electron-hole pairs was apparent in optoelectrical properties of fabricated UV detectors based on the sample with higher concentration of rGO in composite. For this sample, the response time was decreased to 310 ms, and the sensitivity to UV irradiation was increased by 7.7 times. 相似文献
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Composite polymeric particles with ZnS shells 总被引:1,自引:0,他引:1
We report on a preparation of hybrid particles with polymeric cores and ZnS shells. Two types of monodisperse sterically stabilized polystyrene particles with hydroxyl-terminated PEG chains (PS/PEGMA) or β-diketone groups (PS/AAEM) on the surface have been prepared and characterized. Formation of ZnS layer on the surface of submicron particles has been studied by SEM and EDX. Deposition of ZnS on the surface of PS/PEGMA particles is not uniform and leads to formation of ‘raspberry’ morphology with rough surface. It has been found that presence of β-diketone groups on the particle surface leads to formation of well-defined ZnS layers. It has been assumed that such effect is due to the complexation of Zn cations by β-diketone groups leading to nucleation and growth of ZnS crystals on the polymer particle surface. Polymeric particles were completely covered with ZnS if the loaded amount of inorganic material was higher then 40 wt%. The thickness of ZnS layer on the particle surface can be easily varied by changing the ZnS load (in present study maximal thickness of the ZnS shell was 70 nm). It has been found that increase of the ultrasound power leads to considerable increase of the ZnS deposition on the particle surface without strong changes of the particle morphology. Hybrid particles have been investigated with XRD technique and their optical properties were studied by UV-spectroscopy. The colloidal stability of obtained particles was studied by separation analyser. Sedimentation experiments indicate that colloidal stability of obtained composite particles depends strongly on loaded ZnS amount and pH value of the aqueous medium. It has been found that highest sedimentation velocities (or maximum of instability) were determined by ZnS loads, which provide complete coverage of the particle surface. Increase of the ZnS layer thickness led to better stability of hybrid particles in aqueous medium. 相似文献
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Synthesis of Controlled Spherical Zinc Sulfide Particles by Precipitation from Homogeneous Solutions 总被引:4,自引:0,他引:4
Robert Vacassy Stefan M. Scholz Joydeep Dutta Christopher John George Plummer Raymond Houriet Heinrich Hofmann 《Journal of the American Ceramic Society》1998,81(10):2699-2705
Zinc sulfide (ZnS) powders have been obtained by precipitation from homogeneous solutions of various zinc salt compounds, with S2- as precipitating anion, formed by decomposition of thioacetamide. Spherical particles with a very narrow size distribution can be obtained by controlling the synthesis parameters. The particle sizes are influenced by the nature of the associated anion. For example, nanometer-sized ZnS particles are formed using acetate or acetylacetonate anions under acidic pH conditions, controlled by the addition of acetic acid. Although the nucleation is accelerated by the use of acetic acid, limited particle growth occurs because of the formation of complexes with zinc cations that lowers the concentration of free cations in the solution. Also, the complexing-attachment phenomena of the ZnS particles with acetate and acetylacetonate anions lead to the arrest of particle growth processes. The presence of complexed Zn2+ species in the acidic solution is demonstrated both theoretically, using a model based on the calculations of the solubility isotherms of the soluble species, and by Fourier-transform infrared techniques. The nanostructured ZnS particles may provide a suitable semiconductor nanocluster material for optoelectronic applications as well as a phosphor suitable for application in flat-panel display technology. 相似文献
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The dispersion of diamond particles in superplastic zinc sulfide produces flow softening at low diamond concentrations, and hardening at high concentrations. The minimum in the flow stress is observed at 5 wt% (5.5 vol%) diamond content. The softening can be explained in terms of the grain refinement in the ZnS in the presence of diamond particles. The smaller grain size is shown to reduce the flow stress by enhancing the rate of diffusional creep. The hardening is believed to have been caused by the formation of a network among the diamond particles at high concentrations. The fact that the diamond particle size was approximately onethird the grain size of ZnS may have contributed to the network formation. 相似文献
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《Ceramics International》2021,47(23):32938-32946
Increasing the dielectric constant of polymer/sulfide ceramic composites by using wide-bandgap semiconducting sulfide ceramic fillers like ZnS is difficult because of their low interface polarization. To increase the dielectric constant, in this study, ternary polymer-based composite films were designed and fabricated using a hybrid filler consisting of shell-like ZnS particles and core-like V2C MXene particles. First, V2C MXene with a multi-layered structure was synthesized from the simplest raw materials followed by the in-situ hydrothermal growth of ZnS particles around the V2C particles. Then, binary polymer/ZnS and ternary polymer/V2C–ZnS composites were fabricated, and their dielectric, conductive, and electrical breakdown properties were investigated. Finally, the effect of interfacial bonding between the V2C and ZnS phases was investigated by density functional theory calculations, and the contribution of V2C/ZnS interfacial bonding to the higher dielectric constant of the ternary composites than that of the binary composites was explained. The ternary composites exhibited balanced electrical properties suitable for energy storage applications. The ternary composite with 10 wt% hybrid filler loading exhibited a high dielectric constant of ~52, a low dielectric loss of ~0.11 at 100 Hz, and a high electrical breakdown strength of ~202 MV m−1. This study paves the way for the facile fabrication of high-performance composite dielectrics for application in advanced capacitors. 相似文献