ABS/改性抗菌纳米ZnO的力学及抑菌性能

采用偶联剂处理法对抗菌纳米ZnO表面进行改性,制备了丙烯腈-丁二烯-苯乙烯共聚物(ABS)／改性抗菌纳米ZnO复合材料。结果表明:改性抗菌纳米ZnO质量分数为3％时,复合材料的改性效果最佳,其拉伸强度、断裂伸长率、硬度、缺口冲击强度和无缺口冲击强度分别较纯ABS树脂提高37．4％,3．4％,44．0％,15．8％,11．8％;复合材料对大肠杆菌、金色葡萄球菌的抑菌率分别达到76．3％及84．0％。     

烷基二苯醚二磺酸盐的制备与性能表征

制备了一类由刚性基团联接的特殊双亲水基型阴离子表面活性剂———十二烷基二苯醚二磺酸钠(C12-MADS)、双十二烷基二苯醚二磺酸钠(C12-DADS)及十六烷基二苯醚二磺酸钠(C16-MADS),并对其性能进行了研究。25℃时3种烷基二苯醚二磺酸钠的CMC分别为1 16×10-3、1 10×10-5和4 51×10-4mol/L,γCMC分别为44 9、43 5和46 8mN/m,C12-MADS和C16-MADS在浓度分别为2 21×10-2和3 80×10-2mol/L时的胶束聚集数(Nm)分别为24和29。合成的烷基二苯醚二磺酸钠在质量分数高达0 1的无机酸、碱和盐溶液中保持稳定,发泡性低于烷基苯磺酸钠(LAS),但乳化性能优于LAS。C12-MADS在650mg/L硬水中去污比值为14 05%,明显高于LAS(7 18%)。C12-MADS和C12-DADS在4d后的生物降解度≥90%。该类表面活性剂具有优良的应用性能。     

六偏磷酸钠对陶瓷釉料中纳米ZnO分散作用的研究

研究了六偏磷酸钠对纳米ZnO在水体系中和陶瓷釉料体系中的分散作用以及纳米ZnO对陶瓷成品釉面性能的影响.采用沉降实验、粒度分析、釉料流变性、陶瓷成品光泽度和釉料始熔温度测试手段,对含纳米ZnO的水溶液、釉料和陶瓷成品进行了表征.结果表明,在实验条件下,纳米ZnO在水中最佳分散条件为:0.5%六偏磷酸钠,3.0%纳米ZnO,pH为9.在陶瓷釉料中最佳分散条件为:0.5%六偏磷酸钠,4.0%纳米ZnO,pH为9.釉料中含4.0%纳米ZnO的陶瓷制品,光泽度提高5.10%,烧成温度降低约15℃.     

六偏磷酸钠对陶瓷釉料中纳米ZnO分散性的影响

研究了六偏磷酸钠对纳米ZnO在水中和陶瓷釉料中的分散性以及纳米ZnO对陶瓷成品性能的影响.采用沉降实验、粒度分析、釉料流变性、陶瓷成品光泽度、烧成温度测试手段,对含纳米ZnO的水溶液、釉料和陶瓷成品进行表征.结果表明,在实验条件下,纳米ZnO在水中最佳分散条件为0.5%六偏磷酸钠,3.0%纳米ZnO,pH为9.在陶瓷釉料中最佳分散条件为0.5%六偏磷酸钠、4.0%纳米ZnO、pH为9、陶瓷基釉200 mL.以此釉料烧成的陶瓷制品,使光泽度提高7.14%,烧成温度降低约15℃.     

纳米硫酸钡的流变性研究

流变性能是涂料的一种重要性能,纳米硫酸钡作为理想涂料填料的一种,研究了分散剂对纳米硫酸钡的流变特性的影响,考察了分散剂用量、纳米硫酸钡固含量与纳米硫酸钡流变性的关系,利用粘度测定仪对纳米硫酸钡的流变性进行了表征.结果表明：聚丙烯酸钠用量为5％,纳米硫酸钡固含量为43％,粘度随转速变化的范围为40～60 mPa＆#183;s;六偏磷酸钠用量为5％,纳米硫酸钡固含量为43％,粘度随转速变化的范围为11 000～63 000 mPa＆#183;s,呈现出两种不—同粘度范围的非牛顿型流体特性.     

燃烧法制备纳米ZnO及光催化降解甲基橙的研究

分别以甘氨酸和柠檬酸为燃料,Zn（NO3）2为氧化剂,采用燃烧法制备纳米ZnO粉体并采用模拟太阳光进行甲基橙光催化降解研究。XRD和SEM表征样品表明,燃烧法能简单、快速制备纳米ZnO粉体。研究表明,燃烧剂和氧化剂的配比以及反应温度对制备的纳米ZnO降解甲基橙效果有较大影响。Zn（NO3）2与甘氨酸之比为0．2～0．5（物质的量比）,反应温度为5000C;Zn（NO3）2与柠檬酸之比为1．5,反应温度为600℃进行反应制备得到的纳米ZnO降解甲基橙效果较好。降解实验的结果表明,纳米ZnO能有效地光催化降解甲基橙染料。以柠檬酸为燃料制备的ZnO样品,在1h内对10mg·L^-1甲基橙溶液的降解率为90％。     

纳米ZnO／ABS复合材料的制备及性能研究

制备了改性纳米ZnO／丙烯腈-丁二烯-苯乙烯共聚物复合材料，研究改性纳米ZnO用量对复合材料维卡软化温度及紫外线老化前后力学性能的影响。结果表明：适量添加改性纳米ZnO既可有效提高ABS复合材料的维卡软化温度及各种力学性能，又可赋予复合材料优良的耐老化性能。改性纳米ZnO用量为3％时，ABS复合材料的维卡软化温度达102℃，比纯ABS树N（98．7℃）提高3．2℃；紫外线老化前后复合材料的拉伸强度较纯ABS树脂分别提高37．4％和44．6％、断裂伸长率提高0．9％和357％、硬度提高45．4％和29％、缺口冲击强度提高13.8％和44．7％、无缺口冲击强度提高12．4％和44.4％。     

烷基二苯醚二磺酸钠与普通离子型表面活性剂的复配研究

测定了十六烷基二苯醚二磺酸钠(C16-MADS)与十二烷基苯磺酸钠(LAS)以及与十二烷基三甲基氯化铵(DTAC)复配体系的表面张力。研究了这两个复配体系的表面化学性质,并且将正规溶液理论应用于这两个复配体系中,来研究它们形成胶团能力、降低表面张力效率和降低表面张力能力3种增效作用。结果发现：C16-MADS／LAS复配体系具有形成胶团能力和降低表面张力效率的协同效应;C16-MADS／DTAC复配体系具有降低表面张力能力和降低表面张力效率的协同效应;还发现利用正规溶液理论对它们协同效应的判断与实验测定的情况完全相符。     

纳米ZnO改性苯丙外墙涂料的研制及性能研究

采用无机纳米ZnO对苯丙建筑外墙涂料进行改性。结果表明：当纳米ZnO含量为2．0％时效果最好,获得了均匀分布的涂层,涂膜的表面平整、光滑、致密;涂料的耐擦洗性和耐老化性也有显著提高。另外,涂膜干燥时间大大缩短,各项性能都优于未改性苯丙建筑外墙涂料。     

以次磷酸钠为还原剂制备纳米铜粉

研究了以化学还原法与均匀沉淀法相结合的方法制备纳米铜粉。实验以次磷酸钠为制备纳米铜粉的还原性沉淀剂。实验得出较佳工艺条件：硫酸铜浓度0．08～0．5mol／L，次磷酸钠的浓度0．4～1mol／L，还原剂的滴加速度35滴／min，表面活性剂用量占原料质量分数的0．3％，温度50℃，pH=2．0，六偏磷酸钠0．5～2g。对产品进行XRD谱图和TEM电镜分析，证实为纳米级铜粉，但在空气中不稳定，极易被氧化为Cu2O。     

Effect of silica doping on the densification and grain growth in zinc oxide

The ability of silica (SiO₂) in controlling the densification and grain growth behavior of nano crystalline zinc oxide (ZnO) has been systematically studied. It has been observed that SiO₂ acts as a sintering inhibitor in the ZnO–SiO₂ system up to 4 wt.% limiting value beyond which densification behavior of the system remains almost unchanged, especially above 1100 °C. The addition of SiO₂ to ZnO retards grain growth which in turn results a finer ultimate grain size as compared to the undoped ZnO. However, stabilization in grain size occurs at ≥4 wt.% SiO₂ addition. It has been observed that SiO₂ incorporation changes the grain growth mechanism up to 4 wt.% addition, beyond which no remarkable changes was noticed. The grain growth (n) shows distinctly different slopes as a function of sintering time for the SiO₂ doped ZnO systems than undoped ZnO. The different slopes tend to indicate that different diffusion mechanisms and probably the formation of a secondary phase (Zn–Si–O) at the grain boundary control the densification and grain growth. The thermal expansion coefficient of the system has been found to decrease substantially beyond 4 wt.% SiO₂ addition to ZnO.     

Effect of processing on morphological structure of polyacrylonitrile matrix nano‐ZnO composites

The effects of processing methods—free casting and spinning—on dispersion of nano‐ZnO in a polyacrylonitrile (PAN) matrix were studied for this article. From observation with an transmission electron microscope, it was found that monoaxial drawing in spinning processing formed a fiberlike image of the nano‐ZnO phase in the PAN matrix. The geometric parameters—the diameter and ratio of the nanoparticle phase—were about 20 and 15 nm, respectively, when the concentration of nano‐ZnO was 1 wt % in the PAN matrix, whereas spherelike morphology was obtained by free casting, for which, naturally, the ratio of its length to its diameter was unity. This indicates that evidently the morphology of the nanoparticle phase is affected by processing methods. However, when the concentration of nano‐ZnO went up to 2 wt % in the PAN matrix spinning process, the linear ratio of length to diameter of the nanoparticle phase decreased to 2.9 because drawing energy adsorption, through deformation of the nanoparticle phase, became a marked effect. The degree of anisotropy, including crystallization and orientation of polymer, was also affected by the concentration of nano‐ZnO for the same reason. When the concentration of nano‐ZnO reached 2 wt %, the anisotropy of PAN was obviously depressed according to the results of wide‐angle X‐ray measurement. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1053–1057, 2003     

The Effect of Sodium Dodecyl Sulfate (SDS) and Cetyltrimethylammonium Bromide (CTAB) on the Properties of ZnO Synthesized by Hydrothermal Method

ZnO nanostructures were synthesized by hydrothermal method using different molar ratios of cetyltrimethylammonium bromide (CTAB) and Sodium dodecyl sulfate (SDS) as structure directing agents. The effect of surfactants on the morphology of the ZnO crystals was investigated by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) techniques. The results indicate that the mixture of cationic-anionic surfactants can significantly modify the shape and size of ZnO particles. Various structures such as flakes, sheets, rods, spheres, flowers and triangular-like particles sized from micro to nano were obtained. In order to examine the possible changes in other properties of ZnO, characterizations like powder X-ray diffraction (PXRD), thermogravimetric and differential thermogravimetric analysis (TGA-DTG), FTIR, surface area and porosity and UV-visible spectroscopy analysis were also studied and discussed.     

Effect of nano zinc oxide on the cure characteristics and mechanical properties of the silica‐filled natural rubber/butadiene rubber compounds

With the increasing interest in environmental and health issues, legal restrictions, such as European Union (EU) End of Life Vehicle Directives, were strengthened. This led us to incorporate nano zinc oxide (nano‐ZnO), with particle sizes of 30–40 nm and specific surface areas of 25.0–50.0 m²/g, instead of conventional ZnO into natural rubber (NR)/butadiene rubber (BR) compounds to decrease the content of zinc in the formulation. In the unfilled system, only a 20 wt % nano‐ZnO content, compared to conventional zinc oxide content, showed the cure characteristics and mechanical properties of the same level. This was because the increase in the specific surface area of the nano‐ZnO led to an increase in the degree of crosslinking. The effect of nano‐ZnO on the cure characteristics and mechanical properties was more pronounced in the silica‐filled system than in the unfilled system. This was mainly because of the dispersing agent used in the silica‐filled system, which also improved the dispersion of nano‐ZnO. The silica‐filled NR/BR compounds containing 0.3–3.0 phr of nano‐ZnO showed improved curing characteristics and mechanical properties, such as optimum cure time, 100 and 300% modulus, tensile strength, and tear strength compared to the compound with 5 phr of conventional ZnO. The optimum amounts of nano‐ZnO and stearic acid were only 1.0 and 0.1 phr, respectively. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Gelcasting of alumina nanopowders based on gelation of sodium alginate

The alumina nanopowder was synthesized via the sol–gel method. θ-Alumina with crystallite size in the range of 25–110 nm was crystallized by calcination of the powder at 900 °C for 1 h. Sodium alginate, a natural innoxious polymer, was applied for in situ forming process of an Al₂O₃ green body, using calcium phosphate as a solidifier agent. Sodium hexa metaphosphate was also utilized as a chelator. Rheological and gelation behaviors of resultant slurry were analyzed. The viscosity of slurries with 15 vol.% alumina and 1.8 vol.% calcium phosphate dispersed by 1 wt.% sodium alginate solution, was less than 800 mPa s. The green bodies from the gelcasting process were dried at room temperature for 36 h and pressureless sintered at 1500 °C for 3 h. A uniform microstructure without huge grain growth was revealed by SEM.     

Morphology,mechanical property,and modeling evaluation of P(3HB‐co‐4HB)/nano‐ZnO composites

Poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) (P(3HB‐co‐4HB)) and nanometer zinc oxide (nano‐ZnO) modified by solid titanate coupling agent (TMC980) were selected to prepare P(3HB‐co‐4HB)/nano‐ZnO composites via melt blending. Scanning electron microscope (SEM), capillary rheometer, polarized optical microscopy (POM), and universal testing machine were used to characterize the fracture morphology, rheological property, spherulitic morphology, and mechanical properties of P(3HB‐co‐4HB)/nano‐ZnO composites. Halpin‐Tsai equation was used to quantitatively evaluate the dispersion and enhancement effects of modified nano‐ZnO on P(3HB‐co‐4HB). The results demonstrated that modified nano‐ZnO at 0.2%∼0.3% of volume fraction could significantly improve the tensile strength, elastic modulus and toughness, increase the melt viscosity, refine the spherulitic size, and rough the fracture morphology of P(3HB‐co‐4HB)/nano‐ZnO composites. Based on the effective aspect ratio (ξ) from Halpin‐Tsai model evaluation, the optimal dosage of nano‐ZnO for P(3HB‐co‐4HB)/nano‐ZnO composites was also at 0.2%∼0.3% of volume fraction. The Halpin‐Tsai equation was found to predict the experimental data most accurately for the P(3HB‐co‐4HB)/nano‐ZnO composites. POLYM. COMPOS., 37:3113–3121, 2016. © 2015 Society of Plastics Engineers     

TiO2–ZnO/Ni–5wt.%Al composite coatings on GH4169 superalloys by atmospheric plasma spray techniques and theirs elevated-temperature tribological behavior

Ni–based composite coatings with different amounts of TiO₂–ZnO were fabricated by atmospheric plasma spraying (APS) to protect GH4169 superalloy substrates against excess wear and friction at elevated temperatures. In addition, the influence of the simultaneous addition of the oxides on the microstructure, microhardness, and wear behaviour was investigated. According to the results, the simultaneous addition of TiO₂/ZnO provides anti-friction and wear inhibition over 600 °C. In particular at 800 °C, the TiO₂–ZnO/Ni–5wt.%Al composite coating (10 wt% TiO₂ and 10 wt% ZnO were incorporated within Ni–5wt.%Al matrix) exhibits a superior lubricity and wear resistance compared to the Ni–5wt.%Al based coatings. The XRD, Raman, and TEM characterisations reveal the formation of a glaze oxide layer consisting of NiO, TiO₂, ZnO and the in-situ production of ternary oxide (Zn₂TiO₄), which was primarily responsible for the tribological performance of the sliding wear contacts at the specific temperature.     

Preparation and properties of transparent zinc oxide/silicone nanocomposites for the packaging of high‐power light‐emitting diodes

New transparent zinc oxide (ZnO)/silicone nanocomposites with outstanding integrated properties, including a high UV‐shielding efficiency and transparency, bigger thermal conductivity, and lower dielectric constant, were successfully developed; they were prepared by the uniform dispersion of organic modified nano‐ZnO in a silicone matrix through in situ polymerization. The ZnO precursor was prepared by a direct precipitation method, which was then calcinated at different temperatures to produce nano‐ZnO with various morphologies and sizes. The effects of the size, surface nature, and content of nano‐ZnO on the key properties (e.g., optical and dielectric properties, thermal conductivities) of the composites were systematically investigated. The results show that the organic nano‐ZnO prepared by 3‐methacryloxypropyltrimethoxysilane can increase the dispersion of nano‐ZnO in silicone resin, and the interfacial adhesion between inorganic and organic phases, and consequently improve the integrated properties of nanocomposites. The increase of the particle content and size of ZnO in composites can lead to high thermal conductivity and UV‐shielding efficiency but lower visible‐light transparency, so there is an optimum content and size of ZnO in composites to obtain the best integrated properties of the composites. Specifically, the nanocomposite containing 0.03 wt % organic nano‐ZnO with an average size of 46 ± 0.4 nm not only had a high visible‐light transparency, UV‐shielding efficiency, and thermal conductivity but also possessed a low dielectric constant and loss and met the requirements of high‐performance electronic packaging for high‐power light‐emitting diodes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Mechanical and antibacterial properties of modified nano‐ZnO/high‐density polyethylene composite films with a low doped content of nano‐ZnO

Nano‐ZnO/high‐density polyethylene (HDPE) composite films were prepared via melt blending and a hot compression‐molding process. The properties, including ultraviolet absorption, mechanical and antibacterial properties of the films, and plasticizing behavior of the composites, were investigated. The results show that the absorbance in the ultraviolet region of the HDPE films was enhanced after the addition of modified nano‐ZnO to the HDPE matrix. Also, we found that improvement in the HDPE films of the tensile strength and elongation at break was achieved by the incorporation of modified ZnO nanoparticles up to 0.5 wt % in contrast with the original nano‐ZnO/HDPE composite films. Antibacterial testing was carried out via plate counting, and the results indicate that the HDPE films doped with modified ZnO nanoparticles showed favorable antibacterial activity, especially for Staphylococcus aureus. However, the low doped content of modified nano‐ZnO in the HDPE matrix made the balance torque of the composites increase slightly. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Nanomechanical and tribological behavior of hydroxyapatite reinforced ultrahigh molecular weight polyethylene nanocomposites for biomedical applications

A hydroxyapatite (HA) particulate reinforced ultrahigh molecular weight polyethylene (UHMWPE) nanocomposite is fabricated by internal mixer at 180°C and using of paraffin oil as a processing aid to overcome the high viscosity of melted UHMWPE. The reinforcing effects of nano‐HA are investigated on nanomechanical properties of HA/UHMWPE nanocomposites by nanoindentation and nanoscratching methods. Results show that the nanocomposite with 50 wt % nano‐HA exhibits a Young's modulus and hardness of 362.5% and 200% higher, and a friction coefficient of 38.86% lower than that of pure UHMWPE, respectively. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42052.