Synthesis and Rheological Characterization of Water-Soluble Glycidyltrimethylammonium-Chitosan

In this study, chitosan (CS) grafted by glycidyltrimethylammonium chloride (GTMAC) to form GTMAC-CS was synthesized, chemically identified, and rheologically characterized. The Maxwell Model can be applied to closely simulate the dynamic rheological performance of the chitosan and the GTMAC-CS solutions, revealing a single relaxation time pertains to both systems. The crossover point of G′ and Gʺ shifted toward lower frequencies as the CS concentration increased but remained almost constant frequencies as the GTMAC-CS concentration increased, indicating the solubility of GTMAC-CS in water is good enough to diminish influence from the interaction among polymer chains so as to ensure the relaxation time is independent of the concentration. A frequency–concentration superposition master curve of the CS and GTMAC-CS solutions was subsequently proposed and well fitted with the experimental results. Finally, the sol-gel transition of CS is 8.5 weight % (wt %), while that of GTMAC-CS is 20 wt %, reconfirming the excellent water solubility of the latter.     

Fast response photochromic textiles from hybrid silica surface coating

In this study, a hybrid silica sol-gel embedded with a photochromic dye has been applied to wool fabric to form a photochromic coating. The treated wool fabrics showed very quick photochromic response. Five different silanes have been used as the silica precursor, and the resultant coating showed slight differences in photochromic performance, fabric washing fastness, and surface hydrophilicity. However, the silica type had a considerable influence on fabric handle property. The silica matrix from the silane containing a long alkyl chain had a very little influence on the fabric handle and better photochromic performance than those from other different silane precursors.     

稻壳灰制备硅铁红的工艺研究

[目的]研究了稻壳灰制备硅铁红的工艺,为拓宽稻壳灰综合利用途径提供参考。[方法]在微波辐射条件下,采用稻壳灰为原料制备水玻璃,而后以此水玻璃为原料,利用溶胶-凝胶法,在微波辅助干燥条件下制备硅铁红颜料。同时考查了硅/铁摩尔比、微波辐射功率及时间、煅烧温度等因素对硅铁红包裹率的影响。[结果]研究表明,硅/铁摩尔比为7∶1,微波辐射功率和时间分别为600 W和8min,前驱体煅烧温度和时间分别为750℃和2 h;此条件下制备的Fe2O3/SiO2,其包裹率达到93.1%。[结论]在微波辅助下通过简单的sol-gel工艺,可以将SiO2玻璃包裹于Fe2O3颗粒表面而制备出硅铁红包裹颜料并且所制备的硅铁红包裹率高达93%左右,比市售硅铁红的包裹率要高。该工艺操作简单,适合工业化生产。     

Zn_(1-x)Mg_xO薄膜的溶胶—凝胶法制备与光学性质分析

以二水合乙酸锌和四水合乙酸镁为主要原料,石英玻璃为基片,采用溶胶—凝胶法结合旋涂工艺制备Zn1-xMgxO薄膜(x=0、0.1、0.2、0.3).用XRD和分光光度计分别测量薄膜的晶体结构和透射光谱,并对所得谱线进行分析.XRD分析表明,所制备的薄膜仍保持氧化锌的六角纤锌矿结构,未发现形成MgO杂相;Zn0.7Mg0.3O薄膜沿(002)晶面具有一定的择优取向,Mg2+离子替代Zn2+离子进入ZnO晶格,使晶格常数发生变化;随Mg2+离子掺杂浓度的增加,系列样品(002)晶面衍射峰半高宽增大,平均晶粒尺寸递减,(002)晶面的晶面间距略微减小.透射光谱分析表明,随掺杂浓度增高,薄膜在可见光区域内的透光率增大,光学带隙依次增大.     

Pr 3+/TiO2催化剂的制备及光催化性能分析

采用溶胶凝胶法制备了不同浓度、不同煅烧温度下Pr 3+掺杂TiO2光催化剂。对所制样品进行XRD、FT-IR、SEM表征,通过降解碱性品红溶液来测试样品的光催化性能。结果表明稀土Pr 3+掺杂TiO2能细化晶粒,提高热稳定性;在400 ℃下煅烧,摩尔比为n(Pr 3+)/n(TiO2)=0.2%的催化剂,加入氧化剂1 mL30%的双氧水,可以抑制电子和空穴复合,提高催化性能,在无灯源照射条件下,催化时间120 min,降解率达到100%。     

以钼酸钠为熔盐制备硅酸锆晶须

以无水四氯化锆为锆源、正硅酸乙酯为硅源、无水乙醇为溶剂、钼酸钠为熔盐介质,采用非水解溶胶-凝胶工艺结合熔盐法制备硅酸锆晶须,研究熔盐存在条件下硅酸锆干凝胶的物相转变以及熔盐的引入、热处理温度及保温时间等对硅酸锆晶体一维择优生长的影响.熔盐的加入不仅降低了硅酸锆的合成温度,而且对其一维生长有明显促进作用;热处理温度过高或过低、保温时间过长或过短均不利于硅酸锆晶须的形成.850℃保温3h能制备出产率高、直径在50～100 nm,长径比为20～30、沿[001]方向择优生长的硅酸锆晶须.     

Dissolved oxygen sensor based on sol-gel matrix doped with tris(2,2’-bipyridine)ruthenium dichloride

To establish a immobilization method of oxygen sensitive dye, a dissolved oxygen sensor based on a sol-gel matrix doped with ruthenium complex ([Ru(bpy)3]2+) as the oxygen-sensitive material is reported. The results indicate that the I0 /I100 value of the [Ru(bpy)3]2+-doped in tetraethylorthosilane (TEOS) composite films are estimated to be 10.6, where I0 and I100 correspond to the detected fluorescence intensities in pure nitrogen saturated water and pure oxygen saturated water, respectively. Also, the Stern-Volmer plot shows a very good linearity at low dissolved oxygen concentrations. The response time of the composite films is 5 s upon switching from nitrogen saturated water to oxygen saturated water and 10 s from oxygen saturated water to nitrogen saturated water. The dissolved oxygen sensors based on the ruthenium complex/TEOS composite films exhibit greater sensitivity, stability and faster response time as compared to the existing ones. Furthermore, the thin films possess greatly minimized dye leaching effect.     

退火对掺铟氧化锌薄膜结构及光学性能的影响

采用溶胶-凝胶法在石英衬底上制备掺铟氧化锌薄膜,研究不同退火温度对薄膜结构及发光性能的影响.结果表明,掺铟氧化锌薄膜仍为六角纤锌矿结构的ZnO相,在大于450 nm的波段薄膜样品的透射率都较高;随着退火温度的升高,透射率先增后减,600℃时达到最大;薄膜样品的光学带隙都小于纯ZnO的理论值(3.37 eV),且随退火温度的升高呈先减后增趋势;样品的结晶度与发光强度随着退火温度的升高而增强.     

水胺硫磷分子印迹固相微萃取涂层的制备及在果蔬水胺硫磷农药检测中的应用

以聚乙二醇为功能单体,水胺硫磷为模板分子,采用溶胶-凝胶技术,制备水胺硫磷分子印迹固相微萃取涂层,并建立顶空固相微萃取与气相色谱(HS-SPME/GC)联用检测果蔬中水胺硫磷残留量的方法。结果表明,制备的印迹涂层对水胺硫磷具有较高的选择性,且萃取能力大大高于非印迹涂层及常用商用涂层。在最优条件下,建立的检测方法在10～10 000μg/kg范围内线性相关系数为0.999 6,检出限为5.6μg/kg,5次重复实验所得相对标准偏差为2.29%。应用该检测方法测定黄瓜、蕃茄、苹果、梨和大白菜等5种果蔬基质中水胺硫磷含量时,均未有水胺硫磷检出,在5种基质中加标回收率均在89.4%～106.6%之间。     

多孔不锈钢基体上多孔SiO2陶瓷膜的制备

为了研究SiO₂陶瓷在孔径1 μm的多孔不锈钢基体上的成膜性能,利用正硅酸乙酯通过胶溶法制得SiO₂溶胶,对其制备过程中氨水的添加量、胶溶温度和胶溶时间以及SiO₂陶瓷膜层制备过程中溶胶的陈化时间、黏合剂种类、制膜液浓度和烧结温度进行了探讨。结果表明,溶胶制备时氨水的添加量为2.1 mol/mol,胶溶温度50℃,胶溶时间12 h;SiO₂陶瓷膜层制备时溶胶的陈化时间为24 h,黏合剂为聚乙烯醇1750（PVA 1750）,制膜液浓度为0.047 mol/L,烧结温度为850℃;该条件下可以制得连续的颗粒状斜方相SiO₂晶体陶瓷膜。