采用巯基-BPO氧化还原引发体系实现GMA在硅胶微粒表面的高效接枝聚合

使用偶联剂γ-巯丙基三甲氧基硅烷(MPMS,KH-590),对微米级硅胶微粒进行了表面化学改性,制得了表面带有巯基的改性微粒MPMS-SiO2.使改性微粒MPMS-SiO2表面的巯基与溶液中的BPO构成氧化-还原引发体系,实现了油溶性单体甲基丙烯酸缩水甘油酯(GMA)在硅胶微粒表面的引发接枝聚合,制得了接枝度为26g/100g的接枝微粒PGMA/SiO2.采用红外光谱(FTIR)、扫描电镜(SEM)及热重分析(TGA)等方法对接枝微粒PGMA/SiO2进行了表征。在此基础上,重点研究了主要因素对巯基-BPO体系引发GMA接枝聚合的影响.研究结果表明,巯基-BPO体系引发的接枝聚合,由于活性位点位于固体表面,因此也是一种表面引发接枝法。与在固体微粒表面引入可聚合双键的"穿过接枝"("grafting through")法相比,巯基-BPO引发体系可更有效地实现油溶性单体的接枝聚合.为制得高接枝度的接枝微粒PGMA/SiO2,适宜的温度为55℃,适宜的BPO用量为单体的1wt%左右,适宜的单体浓度为10 wt%。     

锦纶织物表面无Sn2+离子敏化活化法化学镀银工艺优化

采用交联壳聚糖预处理锦纶织物后化学镀银,通过正交试验确定了化学镀银的工艺条件:硝酸银14 g·L-1,氢氧化钠6 g·L-1,氨水130 mL·L-1,时间50 min.采用扫描电子显微镜、能量分散谱仪(SEM-EDS)和X-射线衍射(XRD)观察、表征和评价织物镀层的表观形貌、结构组成和摩擦性能.结果表明,织物表面无敏化化学镀银层的晶粒细致、分布均匀,尺寸为28.9 nm,(111)面择优取向较明显,耐摩擦性能好.     

锦纶织物无钯活化化学镀银工艺及性能研究

应用无钯活化化学镀方法在预制聚苯胺层的锦纶织物上沉积金属银,研究了化学镀条件（主盐硝酸银、还原剂葡萄糖、络合剂氨水、氢氧化钠用量、温度和时间）对金属沉积速率和织物方阻的影响.优化化学镀的最佳工艺为：硝酸银12 g/L,葡萄糖2.8 g/L,氨水100 mL/L,氢氧化钠8 g/L,温度30℃,时间50 min.同时讨论...     

表面活性剂改性有机沸石对废水中亚甲基蓝的吸附行为

用表面活性剂十六烷基三甲基溴化铵(CTMAB)和十二烷基硫酸钠(SDS)复合改性沸石,制备了阴阳离子表面活性剂改性沸石,利用X射线衍射和红外吸收光谱表征了改性前后沸石的结构,并研究了改性沸石对亚甲基蓝的吸附行为.结果表明,改性后沸石的吸附性能明显增强;在溶液pH 8、常温,吸附时间100 min、改性沸石用量20 g/...     

稀土镧在腈纶纤维化学镀银中的应用及其电化学性能

采用化学镀法(镀液中加入适量的稀土镧)在硅烷偶联剂改性后的腈纶纤维表面沉积金属银,由粒径分析、X射线衍射、扫描电子显微镜、阴极极化曲线以及循环伏安曲线等方法对其进行表征,研究了硝酸镧对化学镀银沉积速度、镀层质量和电化学性能的影响。结果表明,镀银液中加入适宜的硝酸镧,银的沉积速率和腈纶纤维表面银镀层的表面质量均有不同程度的提高。电化学测试表明,镀银液中增大硝酸镧的浓度(0～0.01 g/L),阴极极化曲线极化度增大,氧化还原峰的电流上升,电沉积的速度加快。     

改性蒙脱土吸附2,4-二氯-5-硝基苯酚的研究

分别采用新型双子阳离子表面活性剂Y-16和十六烷基三甲基溴化铵(CTAB)改性钠基蒙脱土,通过IR、TGA、XRD对其进行表征,研究了表面活性剂的浓度、改性蒙脱土的用量以及接触时间对2,4-二氯-5-硝基苯酚(DCNP)吸附的影响。结果表明:上述两种表面活性剂成功插入钠基蒙脱土层间结构且扩大了其层间距。随着表面活性剂的浓度、改性蒙脱土的用量、接触时间的增加,改性蒙脱土对DCNP的吸附量也随之增加,并达到最大值。当采用0.1g 1.8CEC改性蒙脱土且接触时间为180min时,CTAB-MMT和Y-16-MMT对DCNP达到最大吸附量分别为184.84mg·g~(-1)、164.47mg·g~(-1)。改性蒙脱土对DCNP的吸附行为符合二级动力学方程和Langmuir等温吸附方程。     

空心微珠表面化学镀Ni-Co-P合金

以无机非金属粉煤灰空心微珠为芯材, 利用化学镀工艺对其表面进行金属化改性, 可以得到表面完整包覆的导电粉体, 该粉体具有中空, 质轻, 粒度细, 高强度, 耐高温, 导电性能好等多种优异性能, 可部分代替金属和铁氧体微粉作为电磁波吸收剂. 采用SnCl2和PdCl2进行敏化-活化处理后, 在空心微珠表面化学包覆Ni-Co-P合金层, 利用XRD、EDS、SEM和镶嵌金相等方法对样品进行形貌观察和分析表征, 结果表明, 使用PdCl2作活化剂可以得到优质均匀的Ni-Co-P合金镀层, 镀层光亮, 均匀, 包覆完整. 化学镀后镀层呈非晶态, 450 ℃氢气气氛下热处理后出现结晶相Ni3P和六方晶系的α-Co单质.     

2,2′-联吡啶和亚铁氰化钾对乙醛酸化学镀铜的影响

以乙醛酸作还原剂、Na2EDTA为络合剂、2,2′-联吡啶和亚铁氰化钾作为添加剂组成化学镀铜体系,研究了两种添加剂对化学镀铜速率、镀层表面形貌、组成和结构的影响.结果表明:添加适量的2,2′-联吡啶和亚铁氰化钾,不仅提高了镀液的稳定性,而且使沉积速率增加1倍.这两种添加剂的同时使用,使镀层颜色变亮,形貌发生变化.所得镀层是多晶铜,没有发现夹杂Cu2O.     

2,2''''-联吡啶和亚铁氰化钾对乙醛酸化学镀铜的影响

以乙醛酸作还原剂、Na2EDTA为络合剂、2,2'-联吡啶和亚铁氰化钾作为添加剂组成化学镀铜体系,研究了两种添加剂对化学镀铜速率、镀层表面形貌、组成和结构的影响.结果表明:添加适量的2,2'-联吡啶和亚铁氰化钾,不仅提高了镀液的稳定性,而且使沉积速率增加1倍.这两种添加剂的同时使用,使镀层颜色变亮,形貌发生变化.所得镀层是多晶铜,没有发现夹杂Cu20.     

乙酰丙酮金属配合物表面改性纳米二氧化钛

以乙酰丙酮稀土和乙酰丙酮铁配合物通过吸附法对纳米TiO2进行表面改性,以光催化降解甲基橙为探针反应,在紫外光照条件下考察了改性条件对纳米TiO2催化活性的影响,包括金属元素种类、配合物含量、吸附温度、溶剂用量、吸附时间等.研究表明,乙酰丙酮铁改性纳米TiO2最有效.当w[Fe(acac)3/TiO2]为0.25%,吸附温度为60℃,溶剂用量为乙醇/TiO2等于29 mL/g,吸附1.5 h时,改性后的纳米TiO2催化活性比改性前有了很大的提高.即使在普通白炽灯光照条件下,改性催化剂仍显示出很高的光催化活性,明显优于非改性的纯TiO2.改性纳米TiO2经过IR、XRD、UV-Vis、荧光、SEM-EDS和高倍光学显微镜等分析表征.     

Study on the cationic modification and dyeing of ramie fiber

A modification procedure for ramie fiber using 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (CHPTAC) as a cationic agent and NaOH as a catalyst was developed in this paper. The morphological and structural transformations of the fiber induced by modification were determined by XRD (XRD), differential scanning calorimetry (DSC), and thermogravimetry analysis (TGA). XRD results show that the crystal structure of the modified fiber was still preserved although its crystallinity was decreased, which was confirmed from the TGA results. The mechanisms for the modification and dyeing of ramie fiber were analyzed, and the optimum modification conditions were determined to be the CHPTAC concentration of 30 g L⁻¹, the NaOH concentration of 15 g L⁻¹, the reaction temperature of 50 °C, and the reaction time of 60 min. The raw and the modified fibers were dyed with C.I. reactive red 2. The K/S values for the cationic modified fiber increased to be three times as high as the unmodified fiber. The dye uptakes increased greatly with an increase in the nitrogen contents up to 0.4% on the modified fibers.     

A novel approach for Apocynum venetum/cotton blended fabrics modification by cationic polymer nanoparticles

Apocynum venetum/cotton blended fabrics have been subjected to treat with cationic polymer nanoparticles followed by dyeing with Acid Red B,and then studied for their dyeing performance and morphology.The investigation on the effect of modification factors on the blended fabrics indicated that the 0.5 g/L nanoparticles concentration,60 min treating time,60 °C treating temperature and pH 6-8 are the optimum modification process to improve the dyeability of acid dye.In addition,the SEM images show that nanoparticles can be adsorbed on the surface of modified A.venetum or cotton fibers,and the two different fibers could have the same adsorption ability to Acid Red B.     

Photochemical modification of an optical fiber tip with a silver nanoparticle film: a SERS chemical sensor

We present a method of photochemical modification of an optical fiber tip with a silver nanoparticle film. The deposited silver nanoparticle film displays alternating light and dark circles, which are similar to a radial diffraction pattern. The modified optical fiber is examined as a chemical sensor for in situ detection. The modified fibers show excellent SERS activity, a low limit of detection (LOD), and good reproducibility. The maximum SERS activity of the sensor was achieved within 5.0 min of deposition. Thus, the method is also quite rapid.     

Development of antimicrobial cotton fabric using bionanocomposites

In order to provide antimicrobial activity to cotton, cotton fabrics were treated by montmorillonite (KSF), montmorillonite–dihydroxy ethylene urea (KSF–MDEU), KSF–chitosan (CS) and KSF–CS–MDEU solutions containing 12.5, 25 and 50 ppm silver ion. The effect of modification on the antibacterial activity of cotton fabrics was also evaluated after 10 cycles of washings. MDEU exhibited better antimicrobial activities after washing process. By using 25 ppm silver, KSF and CS modification solution, good performance in terms of antibacterial activity was obtained. The addition of CS and MDEU increased the whiteness index values of cotton fabrics treated with KSF containing different silver concentrations. The characterization of modified cotton samples was done by Fourier transform infrared spectroscopy, X-ray diffraction analysis, inductively coupled plasma-mass spectroscopy, scanning electron microscopy and thermogravimetric analysis.     

An optimal method of DNA silver staining in polyacrylamide gels

A silver staining technique has widely been used to detect DNA fragments with high sensitivity on polyacrylamide gels. The conventional procedure of the silver staining is tedious, which takes about 40-60 min and needs five or six kinds of chemicals and four kinds of solutions. Although our previous improved method reduced several steps, it still needed six kinds of chemicals. The objective of this study was to improve further the existing procedures and develop an optimal method for DNA silver staining on polyacrylamide gels. The novel procedure could be completed with only four chemicals and two solutions within 20 min. The steps of ethanol, acetic acid, and nitric acid precession before silver impregnation have been eliminated and the minimal AgNO3 dose has been used in this up-to-date method. The polyacrylamide gel of the DNA silver staining displayed a golden yellow and transparent background with high sensitivity. The minimum 0.44 and 3.5 ng of DNA amount could be detected in denaturing and nondenaturing polyacrylamide gel, respectively. This result indicated that our optimal method can save time and cost, and still keep a high sensitivity for DNA staining in polyacrylamide gels.     

Adsorption thermodynamic and kinetic of disperse dye on cotton fiber modified with tolylene diisocyanate derivative

Adsorption thermodynamic and kinetic study of disperse dye on cotton fiber modified with tolylene diisocyanate derivative was carried out under the condition of pH value 6.0 ± 0.2, initial dye concentration 0.01–3.0 g/L and liquor ratio 2,000:1. The result showed the equilibrium adsorption isotherm of disperse dye on modified cotton fiber was Langmuir—Nernst mixed Model and the saturated adsorption capacity of the turning point was 7.1429 mg/g. The calculation of the thermodynamic parameters indicated that the Van der Waals’ forces played a major role between the disperse dye and the modified cotton fiber, and the adsorption of disperse dye on the modified cotton fiber was exothermic process. Compared with the diffusion coefficient and the activation energy of disperse dye on various fibers, the disperse dye diffusion in modified cotton fiber was more difficult than that in original cotton. Meanwhile, it was found that the adsorption kinetics of disperse dye on modified cotton fiber was well agreed with a pseudo second-order kinetic model.     

不同结构二元羧酸改性棉纤维铁配合物的制备和光催化性能

分别使用3种不同结构的二元羧酸[酒石酸(TA)、 苹果酸(MA)和丁二酸(SA)]对棉纤维改性引入羧基并与Fe ³⁺离子反应制备羧酸改性棉纤维铁配合物, 考察了二元羧酸结构和浓度对改性棉纤维的羧基含量(Q_COOH)及其铁配合物的铁配合量(Q_Fe)的影响. 研究了3种羧酸改性棉纤维铁配合物作为有机染料氧化降解反应和Cr(Ⅵ)还原反应光催化剂的性能. 结果表明, 改性棉纤维的Q_COOH值随羧酸浓度的增加而增加. 不含羟基的SA比2种羟基羧酸TA和MA能给棉纤维引入更多羧基, 而2种羟基羧酸改性棉纤维铁配合物则具有更高的Q_Fe值. 3种羧酸改性棉纤维铁配合物对染料氧化降解反应和Cr(Ⅵ)还原反应都表现出显著的光催化作用, 且随其Q_Fe和辐射光强度的提高而增强. TA改性棉纤维铁配合物比其它2种配合物具有更高的光催化活性. 3种配合物不但能将Cr(Ⅵ)还原为Cr(Ⅲ)离子, 而且还能将其部分吸附去除, MA改性棉纤维铁配合物具有较高的铬离子去除效率.     

Low-temperature sorption-luminescence determination of silver using silica gel chemically modified with mercaptopropyl groups

Silica gel chemically modified with mercaptopropyl groups extracts silver(I) from solutions in the acidity ranges from 4 M HNO₃ to pH 8 and from 0.01 M HCl to pH 7. The time it takes to attain a sorption equilibrium is no more than 2 min; distribution coefficient is 1 × 10⁵ cm³/g. Yellow-orange luminescence was produced in the adsorbent phase upon the UV irradiation of wet adsorbates cooled to the liquid-nitrogen temperature (77 K). This effect was used for the development of a procedure for the low-temperature sorption-luminescence determination of silver. The calibration graph was linear in the range 1–80 µg Ag per 0.1 g of adsorbent. The detection limit was 0.05 µg per 0.02 g of adsorbent. The relative standard deviation was no more than 6% for silver amounts higher than 5 µg.__________Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 4, 2005, pp. 390–393.Original Russian Text Copyright © 2005 by Losev, Elsuf ev, Trofimchuk.     

双光子微纳加工技术结合化学镀工艺制备三维金属微弹簧结构

利用飞秒激光双光子微纳加工技术与化学镀工艺制备了三维金属微弹簧结构.采用扫描电子显微镜(SEM)及选区电子能谱(EDS)对镀层进行了表征,当化学镀时间为15 min时,所得到的镀层厚度约为130 nm.对不同电镀时间下获得的镀层电阻率进行了测定,实验结果表明,当电镀时间为35 min时得到的镀层电阻率约为80×10^-9 Ω·m,仅为银块体材料电阻率16×10^-9 Ω·m的5倍.利用这种方法,我们制备了总长度为28.75 μm、周期为2.93 μm的悬空金属弹簧结构,其中弹簧圈数为9圈,直径为6 μm,弹簧线分辨率为1.17 μm.文中所述的将双光子微纳加工技术与化学镀技术相结合的方法可以实现任意三维微金属结构与器件的制备,在微光学器件、微机电系统(MEMS)及微传感器等领域有着广泛的应用前景.     

Fast and sensitive method to determine chloroanisoles in cork using an internally cooled solid-phase microextraction fiber

A new generation of solid-phase microextraction (SPME) fiber, an internally cooled fiber (cold fiber with polydimethylsiloxane loading) that allows heating the sample matrix and simultaneously cooling the fiber coating, was used to determine 2,4-dichloroanisole, 2,6-dichloroanisole, 2,4,6-trichloroanisole and pentachloroanisole in cork. A comparison between the cold fiber and regular SPME fiber was performed. An automated headspace solid-phase microextraction (HS-SPME) using commercial fibers and an internally cooled SPME fiber (CF-HS-SPME) coupled to gas chromatography-time-of-flight mass spectrometry (GC-TOF-MS) was used. The extraction conditions for both CF-HS-SPME and HS-SPME were optimized using full factorial design and Doehlert matrix. The best extraction conditions for CF-HS-SPME were obtained using 10 min of incubation time, 10 min of extraction time, and sample and fiber temperature of 130 and 10 degrees C, respectively. For HS-SPME, polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber was used with 10 min of incubation time, 75 min of extraction time, 85 degrees C of sample temperature, 8 ml of water was added and agitated at 500 rpm. The quantification limits for the target compounds using CF-HS-SPME procedure were between 0.8 and 1.6 ng g(-1) of cork, while for HS-SPME were between 4 and 6 ng g(-1) of cork. Furthermore, the CF-HS-SPME procedure could be used as a non-destructive method after minor modification of the agitator for the autosampler.