咪唑封闭水性聚氨酯复鞣剂的制备及表征

通过分子设计,以咪唑为封闭剂,1,6-己二异氰酸酯（HDI）、二羟甲基丙酸（DMPA）、2,2-二（4-羟基苯基）丙烷、聚酯二醇为原料制备出咪唑封闭水性聚氨酯复鞣剂（BPU）。用FT-IR、动态激光光散射（DLS）、TEM、TGA、DSC分别对BPU分子结构、乳胶粒形态及热性能进行了表征,分析了BPU复鞣剂的分子作用基础。结果表明产物分子结构中出现了羧基、咪唑环和聚氨酯结构;乳胶粒呈较为规则的、具有核壳结构的球形,粒径的多分散性是BPU具有良好选择填充性的微观原因。TGA和DSC分析显示BPU耐热性较高并随封闭率增加而略有降低;BPU解封温度范围为107.5～124.5℃,峰值为115.1℃;应用过程中BPU解封程度极低,利于助染性能的提高。     

羧基丁苯胶/封闭聚氨酯纸基复合材料的制备及防水增强作用

以咪唑为端异氰酸酯基封闭剂,制备封闭聚氨酯预聚体,然后以羧基丁苯胶水溶液进行反相乳化,并加入氮丙啶,制得系列水分散羧基丁苯胶/封闭聚氨酯植物纤维防水增强剂(XSBRL/BPU)。XSBRL/BPU的综合性能与BPU封闭率、羧基丁苯胶/封闭聚氨酯比例、交联剂氮丙啶含量及复合乳液的添加量有关。当封闭率BR=10%、m(BPU)/m(XSBRL)=2/1、ω(氮丙啶)=2%、ω(乳液)=8%时,纸基复合材料具有良好防水性能、黏合强度和机械性能,其中,耐折度为158次、施胶度为180s、干抗张指数为63.4N.m.g-1、湿抗张指数为33.8N.m2g-1、湿强度为53.3%。     

封端型硅烷改性阳离子水性聚氨酯纸张湿强剂的研究

通过自乳化法,以异佛尔酮二异氰酸酯(IPDI)、聚四氢呋喃醚二醇(PTMEG)、聚醚三元醇、甲乙酮肟(MEKO)为原料,KH602为硅烷改性剂,制备封端型硅烷改性阳离子封端水性聚氨酯(SCBPU)纸张湿强剂。用傅里叶红外光谱仪(FT-IR)和扫描电子显微镜(SEM)分别对SCBPU分子结构及纸张的表观形貌进行表征,研究了封闭率对粒径及乳液外观和贮存稳定性的影响,并探讨了SCBPU封闭率对纸张力学性能的影响。结果表明,产物分子结构中出现了Si—O—Si和氨基甲酸酯结构。经SCBPU处理后纸张表面孔隙变少,有明显的拉丝状和薄膜状物质。随着封闭率增加,乳液粒径增大,纸张湿强度呈现先增后减的趋势,最佳封闭率为10%。     

咪唑系水性封闭型聚异氰酸酯交联剂的制备与性能

以异佛尔酮二异氰酸酯(IPDI)和2,2-二羟甲基丙酸(DMPA)制备亲水性的异氰酸酯(NCO)封端的线型预聚体,再以预聚体与三羟甲基丙烷(TMP)反应合成支化结构中间体,最后以8种咪唑(IDZ)衍生物分别对残留的NCO基团进行封闭,制得一系列水性封闭型聚异氰酸酯交联剂。以傅里叶变换红外光谱表征了交联剂的结构,以热分析法着重研究了封闭剂的结构对交联剂解封温度的影响,结果表明交联剂的最低解封温度为100℃;稳定性研究表明交联剂在水性聚氨酯乳液中有较好的力学稳定性和适用稳定性。     

聚氨酯/羧基丁苯胶胶乳的表面施胶及其交联对纸张表面强度及耐折度的影响

以聚己内酯二元醇（CAPA）为软缎,甲苯二异氰酸酯（TDI）为硬段,二羟甲基丙酸（DMPA）为亲水单体,采用自乳化法制备了水性聚氨酯乳液,并用此聚氨酯乳液与羧基丁苯胶（XSBRL）以及外加交联剂氮丙啶（aziridine）进行复配制得水性聚氨酯/羧基丁苯胶复合乳液。实验研究了此复合乳液对纸张的表面施胶性能,并优化了合成工艺条件。研究表明,当n能,并且氮丙啶的加入能进一步提高纸张的表面强度和耐折度。     

水下凝胶聚氨酯的制备及其性能研究

研究了水下凝胶聚氨酯的合成、封闭以及在水中解封闭工艺条件,实验结果表明:在亲水性聚醚多元醇中添加10%的油溶性聚醚多元醇,可显著提高水下凝胶聚氨酯的粘接强度。采用添加了油溶性聚醚多元醇的水溶性聚醚多元醇在85℃与甲苯二异氰酸酯预聚,反应时间180min,制得水溶性聚氨酯,对制取的水溶性聚氨酯活性基团进行封闭,以苯酚为封闭剂,氰酚摩尔比为1∶1.2,二月桂酸二丁基锡为催化剂,其用量为0.3%,产品置于热水中解封,凝胶效果良好。     

基于双咪唑离子介质制备高抗菌性聚氨酯的研究

利用阴离子交换反应合成阴离子为PF_6~-的双咪唑基离子二醇([BmimPF_6~-]-OH)新型扩链剂,并由此制备出一种双咪唑离子介质固载的聚氨酯([BmimPF_6~-]-PU)。通过核磁、红外光谱对其结构进行了表征,并研究了该聚氨酯的抗菌性能。结果表明:双咪唑离子介质的引入,赋予聚氨酯高效的抗菌性。在[BmimPF_6~-]-OH含量达22.86%(wt,质量分数)时,该类聚氨酯对大肠杆菌的抑菌率超过99.9%,对金黄色葡萄球菌的抑菌率达到99.4%。     

光引发聚氨酯微胶囊的制备及涂层自修复性能

以聚氨酯丙烯酸酯RJ423、1,6-己二醇二丙烯酸酯(HDDA)、光引发剂1173为芯材，以六亚甲基二异氰酸酯三聚体(HDI三聚体)和聚乙二醇(PEG2000)为单体合成聚氨酯壁材，采用界面聚合法制备了光引发聚氨酯自修复微胶囊。通过傅里叶变换红外光谱仪(FT-IR)、扫描电子显微镜(SEM)、热重分析仪(TG)、激光粒度分析仪以及万能拉伸试验机分别对微胶囊的结构形貌、热稳定性、粒径分布及涂层力学性能进行了测试与表征。结果表明，当芯壁比1∶1.5,乳化剂浓度1%,均化速度8000r/min,制备的微胶囊为规则的球形，且表面形貌规整，产率和包覆率分别达到52.14%、48.36%。且微胶囊均匀地分在在乳胶膜中并具有良好的自修复性能，并且在微胶囊含量为4%时乳胶膜的力学性能和自修复性能最佳。     

甲乙酮肟封闭水性多异氰酸酯的合成及表征

利用甲苯二异氰酸酯(TDI)、三羟甲基丙烷(TMP)与二羟甲基丙酸(DMPA)反应,三乙胺(TEA)中和成盐及甲乙酮肟(MEKO)封端反应后,制得一种水分散性封闭多异氰酸酯(WBI)。研究了封闭时间对封闭率的影响,封闭顺序对反应的影响。采用FT-IR、TGA、DSC研究了其解封温度。实验结果表明,甲乙酮肟封闭反应的较好条件为:摩尔比n(MEKO)∶n(-NCO)为1.1～1.2;反应温度为70℃;反应时间3.0h,可实现较完全的封闭,其解封温度为70～128.8℃。作为涂料固化剂可明显改善漆膜性能。     

封闭型聚氨酯的研究

首次利用新型封闭剂———乙酰苯胺,在70℃以H/NCO为1.2的条件下,实现了对聚醚和TDI的聚氨酯预聚体的封闭,实验证实,该封闭剂封闭的聚氨酯具有较低的解封温度(90℃),并通过FTIR进行了表征。     

Pesticide adsorption in relation to soil properties and soil type distribution in regional scale

Study was focused on the evaluation of pesticide adsorption in soils, as one of the parameters, which are necessary to know when assessing possible groundwater contamination caused by pesticides commonly used in agriculture. Batch sorption tests were performed for 11 selected pesticides and 13 representative soils. The Freundlich equations were used to describe adsorption isotherms. Multiple-linear regressions were used to predict the Freundlich adsorption coefficients from measured soil properties. Resulting functions and a soil map of the Czech Republic were used to generate maps of the coefficient distribution. The multiple linear regressions showed that the K(F) coefficient depended on: (a) combination of OM (organic matter content), pH(KCl) and CEC (cation exchange capacity), or OM, SCS (sorption complex saturation) and salinity (terbuthylazine), (b) combination of OM and pH(KCl), or OM, SCS and salinity (prometryne), (c) combination of OM and pH(KCl), or OM and ρ(z) (metribuzin), (d) combination of OM, CEC and clay content, or clay content, CEC and salinity (hexazinone), (e) combination of OM and pH(KCl), or OM and SCS (metolachlor), (f) OM or combination of OM and CaCO(3) (chlorotoluron), (g) OM (azoxystrobin), (h) combination of OM and pH(KCl) (trifluralin), (i) combination of OM and clay content (fipronil), (j) combination of OM and pH(KCl), or OM, pH(KCl) and CaCO(3) (thiacloprid), (k) combination of OM, pH(KCl) and CEC, or sand content, pH(KCl) and salinity (chlormequat chloride).     

Preconcentration and determination of trace metal ions from aqueous samples by newly developed gallic acid modified Amberlite XAD-16 chelating resin

Gallic acid was immobilized on Amberlite XAD-16 by coupling it through -N=N group. The resulting chelating resin Amberlite XAD-16 gallic acid, characterized by thermogravimetric analysis (TGA), infrared (IR) spectra and BET analysis, was used to preconcentrate Cr(III), Mn(II),Fe(III),Co(II), Ni(II) and Cu(II)ions. The resin was employed for the preconcentration of the metal ions present in river water and industrial area aqueous samples. Several parameters like effect of pH, effect of time, effect of sample volume and flow rate of sample were investigated. The sorption capacities for the resin were 216 micromol g(-1), 180 micromol g(-1), 403 micromol g(-1), 281 micromol g(-1), 250 micromol g(-1) and 344 micromol g(-1) for Cr(III), Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) respectively. The preconcentration factors for Cr(III), Mn(II), Fe(III), Ni(II), Co(II) and Cu(II) were found out to be 300, 200, 400, 285.7, 300 and 400 respectively. The effect of various interfering ions was also studied. Results were validated by using standard addition method for river water sample.     

Extensive measurements of H216O line frequencies and strengths: 5750 to 7965 cm(-1)

High-resolution spectra of H(2)(16)O vapor covering the region from 5750 to 7965 cm(-1) were used to determine experimental values of line positions and strengths of over 3750 vibration-rotation transitions in the (110)-(000), (011)-(000), (040)-(000), (120)-(000), (021)-(000), (200)-(000), (101)-(000), (002)-(000), (031)-(010), (210)-(010) and (111)-(010) bands from which rotational energy levels in the (040), (120), (021), (200), (101) and (002) vibrational states were obtained. The line strengths and frequencies reported here are considered to be a marked improvement over the values listed in the 1986 edition of the HITRAN database, and a preliminarly listing from this work has been included in the 1993 HITRAN edition.     

The prediction of the dissolution rate constant by mixing rules: the study of acetaminophen batches

The purpose of this article is to promote two simple and scalable methods to accelerate the formulation development of formulated granules using acetaminophen as a model system. In method I, formulated granules made from the batch of small particle-sized acetaminophen (1) by ball milling the batch of large particle-sized acetaminophen (2), and the mixture of the two batches at equal weights (mix) gave the dissolution rate constants (k) of k(1) = 0.43 +/- 0.15 minutes(-1), k(2) = 0.18 +/- 0.01 minutes(-1), and k(mix) = 0.30 +/- 0.03 minutes(-1) for 75 wt percent formulation; k(1) = 0.75 +/- 0.01 minutes(-1), k(2) = 0.18 +/- 0.01 minutes(-1), and k(mix) = 0.34 +/- 0.03 minutes(-1) for 62 wt percent formulation; and k(1) = 0.28 +/- 0.01 minutes(-1), k(2) = 0.16 +/- 0.01 minutes(-1), and k(mix) = 0.22 +/- 0.02 minutes(-1) for 30 wt percent formulation. In method II, the mixture of the formulated granules produced by mixing the formulated granules from the two batches at equal weights gave dissolution rate constants of k(mix) = 0.30 +/- 0.03 minutes(-1), 0.30 +/- 0.02 minutes(-1), and 0.22 +/- 0.01 minutes(-1) for 75 wt percent, 62 wt percent, and 30 wt percent formulations, respectively. After fitting the three data points of k(1), k(2), and k(mix) to the 10 mixing rules in materials science--series mixing rule, Hashin and Shtrikman upper bound, logarithmic mixing, Looyenga mixing rule, effective media approximation (EMA), three-point lower bound, Torquato approximation, three-point upper bound, Maxwell mixing rule, and parallel mixing rule--we found that the selection of the best suited mixing rules based on k(1), k(2), and k(mix) was solely dependent on the formulations under a given operating condition and regardless of whether the system was a powder mixture or a granular mixture. The values of k(1), k(2), and k(mix) in both the 75 wt percent and 30 wt percent formulations were enveloped by the parallel mixing rule and Maxwell mixing rule, whereas the values of k(1), k(2), and k(mix) for the 62 wt percent formulation were encompassed by the logarithmic mixing rule, Hashin and Shtrikman upper bound, and the series mixing rule. Apparently, the best suited mixing rules could be used to predict the right proportions of either the powder mixture (Method I) or the granular mixture (Method II) for obtaining any other desired dissolution rate constant, k(mix), whose value fell in between the values of k(1) and k(2).     

Transition frequencies and strengths of H217O and H218O: 6600 to 7640 cm(-1)

High-resolution spectra of O(17)- and O(18)-enriched water-vapor samples have been recorded with a Fourier transform spectrometer covering the region between 6600 and 7640 cmcm(-1). Experimental values of line positions and strengths of 1807 absorptions in the (120)-(000), (021)-(000), (200)-(000), (101)-(000), (002)-(000), bands of the two isotopic species were derived from the spectra. The analysis included the determination of accurate rotational levels belonging to the (120), (021), (200), (101), and (002) vibrational states of H(2)(17)O and H(2)(18)O.     

Hiral Effects of Single Wall Carbon Nanotube Fluorination and Hydrogenation

Abstract

In the paper the results of calculations of the electronic and energy characteristics of atomic hydrogen and fluorine adsorption processes on an external surface of single wall hiral carbon nanotubes (n, m) are represented. Molecular cluster model within a framework of quantum chemical semi‐empirical schemes MNDO and PM3 has been used. Sorption properties of (4, 1), (4, 2), (4, 3), (5, 1), (5, 3), (5, 4), (6, 1), (6, 2), (6, 3), (6, 4), and (6, 5) tubes have been considered. Periodical behavior of the chemical bond and activation energies as nanotube diameter functions has been found. It appeared that (4, 2), (4, 3), (5, 1) nanotubes show more effective adsorption processes and (5, 3), (5, 4), (6, 2), (6, 3) tubes are not advantage for the chemisorptions.     

A Calixarene-Based Fluorogenic Reagent for Selective Mercury(II) Recognition

The first calixarene-based fluorogenic Hg(II)-selective extractant, 5,11,17,23-tetrakis(1,1-dimethylethyl)-25,27-bis(N-(5-dimethylaminonaphthalene-1-sulfonyl)carbamoylmethoxy)-26,28-dimethoxycalix[4]arene (2), is reported. In solvent extraction from aqueous acidic solutions (HNO(3)), 2 exhibits excellent selectivity for Hg(II) over a wide range of transition, alkali, and alkaline earth metal cations. Quenching of its fluorescence due to Hg(II) coordination is unaffected by the presence of 100-fold excesses of alkali metal cations, alkaline earth metal cations, Ag(I), Tl(I), Cd(II), Co(II), Cu(II), Ni(II), Pb(II), Pd(II), Zn(II), or Fe(III).     

Ion-Pair Extraction of Metalloporphyrins into Acetonitrile for Determination of Copper(II)

Equilibrium study of ion-pair extraction of a cationic water-soluble porphyrin [5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin, H(2)tmpyp(4+)] and its metalloporphyrins (MP) into the acetonitrile layer, separated by addition of sodium chloride (4.00 mol dm(-)(3)) to a 1:1 (v/v) acetonitrile-water mixed solvent, was carried out to develop a new and useful method for the determination of a subnanogram amount of copper(II). M denotes Zn(2+), Cu(2+), Co(3+), Fe(3+), and Mn(3+), and P(2)(-) is porphyrinate ion. The extraction and dissociation constants of the ion-pair complexes, defined by K(ex) = [MP(ClO(4))(4)](org)[MP(4+)](aq)(-)(1)[ClO(4)(-)](aq)(-)(4), K(dis,1) = [MP(ClO(4))(3)(+)](org)[ClO(4)(-)](org)[MP(ClO(4))(4)](org)(-)(1), and K(dis,2) = [MP(ClO(4))(2)(2+)](org)[ClO(4)(-)](org)[MP(ClO(4))(3)(+)](org)(-)(1), were determined by taking into account the partition constant of sodium perchlorate (K(D) = 1.82 ± 0.01). The equilibrium constants were found to be K(ex)K(dis,1) = (7.2 ± 1.3) × 10(4), (6.4 ± 0.9) × 10(4), (1.35 ± 0.13) × 10(5), (4.8 ± 0.6) × 10(3), (1.23 ± 0.05) × 10(4), and (1.42 ± 0.07) × 10(3) at 25 °C for the free base porphyrin (H(2)tmpyp(4+)) and the metalloporphyrins of zinc(II), copper(II), cobalt(III), iron(III), and manganese(III), respectively. The K(dis,2) values were (2.9 ± 1.4) × 10(-)(2), (3.1 ± 1.1) × 10(-)(2), (8.0 ± 4.9) × 10(-)(3), and (5.1 ± 2.2) × 10(-)(2) for the free base porphyrins and the metalloporphyrins of zinc(II), copper(II), and cobalt(III), respectively. The results were developed for determination of a trace amount of copper(II) (3 × 10(-)(8)-4 × 10(-)(6) mol dm(-)(3)) in natural water samples using H(2)tmpyp(4+) with a molar absorptivity of 3.1 × 10(5) mol(-)(1) dm(3) cm(-)(1) at a precision of 1.3% (RSD). The determination of copper(II) was not interfered by the presence of 10(-)(4) mol dm(-)(3) of Mn(2+), Co(2+), Ni(2+), Hg(2+), Cd(2+), Ag(+), Cr(3+), V(5+), Al(3+), Mg(2+), Ca(2+), Br(-), I(-), SCN(-), and S(2)O(3)(2)(-) and 10(-)(5) mol dm(-)(3) of Fe(3+), Zn(2+), and Pd(2+).     

The bonding of heavy metals on nitric acid-etched coal fly ashes functionalized with 2-mercaptoethanol or thioglycolic acid

Coal fly ash is a waste by-product of the coal fire industry, which generates many environmental problems. Alternative uses of this material would provide efficient solutions for this by-product. In this work, nitric acid-etched coal fly ash labelled with 2-mercaptoethanol or thioglycolic acid was assessed for retention of Al(III), As(III), Cu(II), Cd(II), Fe(III), Mn(II), Hg(II), Ni(II), Pb(II) and Zn(II) ions. The bonding characteristics between the organic compounds with the solid support, as well as with the metal ions, were evaluated using various surface analytical techniques. Visualization of the organically-functionalized coal fly ash particle was possible using scanning electron microscopy (SEM), while the elemental composition of the functionalized material, before and after retention of the metal ions, was obtained by energy dispersive (ED)-X ray spectrometry (XRS) and electrothermal atomic absorption spectrometry (ETAAS). Fourier transform infrared (FT-IR) spectrometry and Raman spectrometry were used to obtain information about the functional groups. It was found that some metal(oid) ions (As, Ni, Pb, Zn) were coordinated through the mercaptan group, while other metal(oid)s (Al, Cd, Cu, Fe, Hg, Mn) were apparently bonded to oxygen atoms. A low-cost and effective solid phase retention system for extraction of heavy metals from aqueous solutions was thus developed.     

Theoretical Migration Model for Micellar Capillary Electrophoresis and Its Application to the Separation of Anionic Metal Complexes of HEDTC and CDTA

A mathematical model relating the effective mobility of an analyte in micellar capillary electrophoresis (MCE) to the concentration of surfactant and organic modifier in the background electrolyte (BGE) was derived. Effective mobility is expressed in terms of the electrophoretic mobility of the analyte, the partition coefficient of the analyte into the micelle, and the influence of organic modifier on these two factors. The performance of the model was evaluated using Cd(II), Pb(II), Co(II), Ni(II), Bi(III), Cu(II), and Hg(II) complexes of bis(2-hydroxyethyl)dithiocarbamate, all of which carry a partial negative charge, and Cd(II), Pb(II), Co(II), Ni(II), Bi(III), Cu(II), Hg(II), Fe(III), Ag(I), Tl(I), and Mn(II) complexes of trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid, all of which are anionic having charges in the range -1 to -3. These analytes were separated in borate BGEs containing 10-50 mM sodium dodecyl sulfate and 0-20% (v/v) methanol. Nonlinear regression was used to derive parameters for the model from experimental data and these parameters were used to predict effective mobilities of the analytes. Predicted values of effective mobilties agreed with experimental values to within 3.1%. Values of parameters from the model equation are used to explain changes in separation selectivity observed at different BGE compositions and the model equation is shown to be applicable to computer-assisted optimization of the BGE composition, in MCE using a limited number of experiments.