低VOC低成膜温度水性聚氨酯分散体的合成与表征

以环氧树脂、甲基丙烯酸甲酯(MMA)和丙烯酸羟丙酯(HPA)复合改性水性聚氨酯(WPU),制得以丙烯酸酯为核,聚氨酯为壳,HPA为核壳之间桥连的核壳交联型PUA复合乳液。实验研究结果表明:这种复合乳液可以达到较高硬度漆膜(1H以上),最低成膜温度(2～5℃左右)。MMA添加量增大,涂膜硬度、耐水性逐渐提高,乳液的稳定性则随着降低。当MMA含量为20%左右时综合性能较好。     

周期性多发光层结构单色有机电致发光器件的研究

以具有高离化能的n型小分子材料PBD、BCP作为激子限制层,用交替沉积的方式制备了分别以Alq3/PBD、NPB/BCP为周期结构多发光层的绿光、蓝光器件.周期性多发光层结构的引入大大提高了器件性能,其中,具有双周期3发光层的绿光器件最大亮度和效率分别是常规器件的10.5倍和4.4倍,具有双周期双发光层的蓝光器件最大亮度和效率分别是常规器件的2.75和1.45倍.器件性能提高的主要原因是周期性结构的引入和多发光区域的划分增加了激子产生几率.同时,周期数对器件性能有重要影响.绿光、蓝光器件电致发光(EL)谱谱峰值基本稳定,半高谱宽出现了窄化.     

磁性核壳结构Ce掺杂氧化锆的制备及其As(Ⅲ)吸附性能（英文）

采用溶剂热法和溶胶–凝胶法制备磁性介孔As(Ⅲ)吸附剂Fe₃O₄@SiO₂@Ce-ZrO₂。该核壳结构材料具有高比表面积(168.2 m²/g)和快速磁分离性能(5.37 A·m2/kg)。与Fe₃O₄@SiO₂@ZrO₂相比,Ce掺杂样品的As(Ⅲ)平衡吸附量提高12%-23%(pH3-11),这主要归因于双金属M—O—As配合物的形成。共存的SO₄^2-和PO₄^3-会削弱As(Ⅲ)的吸附,Ca²⁺对除As(Ⅲ)有积极作用,而Cl^-和NO₃^-的影响很小。在初始As(Ⅲ)浓度5mg/L、313K和pH中性条件下,As(Ⅲ)最大吸附容量可达24.52 mg/g。准二级模型对As(Ⅲ)吸附动力学数据的拟合效果良好。此外,吸附...     

水热法一步合成核壳型TiO2/Al2O3纳米粉体的热力学分析

水热法一步合成核壳结构的工艺路线具有简化生产工艺、大大缩短生产时间的特点.所以研究制备具有核壳结构的前驱体热力学条件有重要的指导意义.热力学分析表明,在纳米Ti(OH)4表面包覆Al(OH)3的过程中,存在核包覆和膜包覆的竞争;而在其它条件不变的情况下,包覆物的过饱和度对包覆形态起到了决定性的影响.在较低的过饱和度下,可形成膜包覆;如果过饱和度过高,则形成核包覆.     

巯基乙酸稳定的CdSe/ZnS核壳结构量子点的制备与表征

用非均相成核原理,在水溶液中制备CdSe/ZnS核壳结构量子点,并研究合成工艺,包括前驱物的滴加方式和用量、CdSe核的水浴反应时间、CdSe与ZnS的摩尔比等因素对CdSe/ZnS核壳结构量子点荧光性能的影响.用透射电子显微镜和x射线衍射仪测试核壳结构量子点的形貌和结构.用紫外吸收光谱与荧光光谱表征CdSe/ZnS核壳结构量子点的荧光性能.结果表明:ZnS壳层在CdSe核量子点表面外延生长,形成了核壳结构;CdSe/ZnS核壳结构量子点的荧光性能明显高于单一的CdSe量子点;合成的工艺条件会显著影响CdSe/ZnS核壳结构量子点的荧光性能.     

光激化学发光免疫检测探针材料的设计与制备

光激化学发光免疫检测具有无背景荧光干扰、均相免洗的优势,在体外诊断快速检测领域中具有重要的应用前景。然而,该检测技术所用探针材料的稳定可控制备仍是该技术产业化应用的主要难点之一。采用PVP调控的共聚法,制备的负载铕螯合物Eu(DBM)₃Phen和硫氧杂环己烯衍生物PCU的聚苯乙烯纳米球作为受体球。采用介孔二氧化硅包覆,制备的负载光敏剂Ce6的Fe₃O₄@mSiO₂纳米球作为磁控驱动的供体球。利用扫描电子显微镜、透射电子显微镜、能谱仪等手段对受体球和磁控供体球进行表征。结果表明：受体球呈规则球形且尺寸均一,平均粒径约为200 nm,易分散于水,能与单线态氧作用而发光,最大发射波长约为615 nm;磁控供体球呈球形核壳结构,平均粒径约为700 nm,易分散于水中,在波长680 nm光照下能产生单线态氧,可用磁铁分离。分别用兔IgG和羊抗兔IgG修饰磁控供体球和受体球,结果显示两者之间能发生有效的特异性结合,用磁铁分离去除非特异性结合的探针球后,成功测得光激化学发光信号,证明了两种探针材料的成功制备。     

中空聚合物微球的制备——种子及核乳胶粒的制备

为了制得具有中空结构的聚合物微球,首先以十二烷基苯磺酸钠(SDBS)为乳化剂,在其用量低于CMC的条件下,进行甲基丙烯酸甲酯(MMA)、甲基丙烯酸(MAA)和丙烯酸丁酯(BA)的乳液聚合,制备了带羧基的种子乳胶粒.然后采用MMA、MAA和二乙烯基苯为单体进行种子乳液聚合,制备了轻度交联的带羧基的核乳胶粒.该核乳胶粒经过核-壳乳液聚合和适当的碱处理工艺就可成为具有中空结构的聚合物微球.采用粒度仪测定了乳胶粒的直径及其分布,采用TEM对乳胶粒结构形态进行了表征.研究了种子及核乳胶粒制备过程中单体加料方式、乳化剂用量及羧基单体种类等因素对聚合稳定性、乳胶粒直径及其分布以及最终的中空聚合物微球结构形态的影响,确定了制备种子及核乳胶粒的最佳工艺条件.在制备种子阶段,SDBS用量为单体总量的0.5%,采用一次性加入单体的进料工艺;在核乳胶粒制备阶段,以MAA为羧基单体,所有单体采用"饥饿式"加料,半连续补加乳化剂并使乳化剂用量为核单体总量的0.15%时可保持聚合稳定性并保证无新乳胶粒生成.     

Utilizing the autocatalysis of Co to prepare low-cost WC-Co powder for high-performance atmospheric plasma spraying

A novel method of incorporating fluidized bed chemical vapor deposition (FBCVD) with electroless plating was developed to effectively prepare the core-shell structured WC-Co composite powders. The Co nanoparticles decorated on the surface of WC particles by FBCVD acted as active catalysts for the subsequent electroless plating process. The particle size and quantity of the decorated Co particles determined the electroless plating rate but the particle size played more important role. For the conditions tested, the maximum electroless plating rate of 2.34 mg/g/min was obtained by using an optimal FBCVD pretreatment at 750°C for 3 minutes. WC-12Co composite powders with a commercial composition widely used for atmospheric plasma spraying (APS) were efficiently prepared. The composite powders exhibited excellent suitability for APS by forming a homogenous Co-W-C ternary liquid stream. The APS coating is not only well-bonded with the substrate but also consisted of hard nonequilibrium Co₃W₃C and W₂C phases with a uniform distribution. Both remarkably improved the hardness and tribological properties of the APS coating.     

Fabrication of novel silicon carbide-based nanomaterials with unique hydrophobicity and microwave absorption property

Novel SiC-based nanomaterials, namely the nitrogen and aluminum co-doped SiC@SiO₂ core-shell nanowires and nitrogen-doped SiO₂/Al₂O₃ nanoparticles, have been fabricated through a facile thermal treatment process based on the chemical vapor deposition and vapor-liquid reaction. These nanomaterials show remarkable hydrophobicity with a water contact angle (CA) over 140°, which are aroused by the surface zigzag morphology of the nanostructures and the hydrocarbyl groups generated during the preparation process. Moreover the nanocomposites also exhibit relatively prominent microwave absorption (MA) properties in the frequency range of 2.0-18.0 GHz. The minimum reflection loss (RL) value as low as −23.68 dB can be observed at 14.16 GHz when the absorber thickness is 2.6 mm with a loading rate of 16.7 wt%. And the nanocomposites-based absorbent can achieve an effective absorption bandwidth (RL < −10 dB) of 4.48 GHz with the absorbent thickness of 2.5 mm. This enhanced microwave attenuation performance can be attributed to multiple polarizations and perfect impedance matching conditions, as well as multiple internal reflections. These marvelous properties make these N and Al co-doped SiC@SiO₂ core-shell nanowires and N-doped SiO₂/Al₂O₃ nanoparticles display extensive application potential as MA materials in harsh environment.     

纳米内核-成核剂复合助剂及与PP复合材料的制备和性能

为克服现有助剂(成核剂等)在聚烯烃中产生气味、气泡及性能不稳定等复杂问题,用纳米S iO2前驱物与其对称结构的羟基进行接枝反应,发挥非对称结构效应。结果表明,改性成核剂制备的组合助剂与聚丙烯形成的复合材料,热变形温度达142℃,热收缩率小于1%,500 h力学性能保持率大于90%,纳米效应及使用效果十分显著。