Preparation and surface properties of latexes with fluorine enriched in the shell by silicon monomer crosslinking

A series of core-shell acrylic copolymer latexes containing fluorine enriched in the shell have been prepared by emulsion polymerization of a variety of hydrocarbon monomers with (perfluoroalkyl)methyl methacrylate and vinyltriethoxysilicone. In the presence of a reactive anionic and a long chain anionic-nonionic emulsifier, the core-shell latexes were prepared and characterized by transmission electron microscopy (TEM) and tapping-mode atomic force microscopy (AFM). From AFM and contact angle measurements, it was observed that the resulting fluorine and silicon-containing acrylic copolymers with surface energy as low as 15.5 mN/m formed a dense and gradient film containing a surface layer with high a fluorine content, and that the fluorinated particles can be fixed on the surface due to the crosslinking reaction of multi-functional silicon monomer even though the fluorinated carbon number was not enough to crystallize.     

分散固相萃取结合气相色谱-高分辨质谱快速筛查酱油中多种氯丙醇

建立了酱油中1，3-二氯-2-丙醇、2，3-二氯-1-丙醇、3-氯-1，2-丙二醇和2-氯-1，3-丙二醇的分散固相萃取-气相色谱-高分辨质谱快速筛查检测方法。样品采用乙酸乙酯提取，提取液浓缩后经N-丙基乙二胺净化，气相色谱-高分辨质谱测定，内标法定量。结果表明，该方法对于酱油中4种氯丙醇的定量限为0.5~10 μg/kg。在3个浓度水平下的加标回收率为78%~103%；相对标准偏差均不大于8.8%。该方法快速、简便、准确、灵敏，可作为酱油中4种氯丙醇的有效检测方法。     

利用高炉水淬渣制备(Ca/Y)-α-Sialon陶瓷的组织与性能

以高炉水淬渣合成的Ca-α-Sialon粉体为原料采用无压烧结技术制备了（Ca/Y）-α-Sialon陶瓷。通过用排水法、三点弯曲实验法、金相显微镜法、XRD法等手段研究了（Ca/Y）-α-Sialon陶瓷的烧结致密化过程、材料的力学性能、显微组织、相组成和材料的断裂特征。结果表明,适量的Y2O3促进材料的烧结致密化和提高材料的力学性能,但Y2O3过量（大于10%）时对材料的烧结和力学性能不利。掺杂Y^3＋的（Ca/Y）-α-Sialon呈柱状晶,随着Y2O3含量的增加和烧结温度的提高,（Ca/Y）-α-Sialon呈柱状晶出现粗化和等轴化。含10%Y2O3的材料在1700℃烧结时可获得较高的力学性能。     

A novel method of the separation/preconcentration and determination of trace molybdenum(VI) in water samples using microcrystalline triphenylmethane loaded with salicyl fluorone

It is the first time that triphenylmethane was used as an adsorbent to preconcentrate and separate trace amount of molybdenum in water samples. The effects of different parameters, such as acidity, stirring time and various metal ions, the amounts of triphenylmethane and salicyl fluorine, etc. on the enrichment yield of molybdenum have been studied to optimize the experimental conditions. Under the optimum conditions, molybdenum can be adsorbed on the surface of microcrystalline triphenylmethane loaded with salicyl fluorone by the intermolecular action strength. The possible reaction mechanism for the enrichment of molybdenum was discussed in detail in this paper. Mo(VI) can be completely separated from Pb(II), Co(II), Cu(II), Cr(III), Ni(II), Hg(II), Zn(II), Cd(II), Fe(III) and Al(III) in the solution. The proposed method was successfully applied to the determination of trace amount of molybdenum in various water samples by spectrophotometry after preconcentration using microcrystalline triphenylmethane. The preconcentration factor is from 83 (500 ml water sample was enriched to 6.0 ml) to 166 (1000 ml water sample was enriched to 6.0 ml). The detection limit is 1.3 × 10⁻⁵ mg l⁻¹ and the linearity is maintained in the concentration range 3.8 × 10⁻³ to 0.36 mg l⁻¹ with a correlation coefficient of 0.9998. The recoveries are in the range of 93.5-104%. The relative standard deviation is 1.8-2.9%. Analytical results obtained with this novel method are very satisfactory.     

配合物[Li(THF)_2]_2(μ—Cl)_4[(η~5—CH_3C_5H_4)Nd·THF]的合成及其晶体结构

环戊二烯基希土氯化物是一类合成希土有机配合物的重要前身。尽管在1980年前没能成功地合成含轻希土元素的这类配合物,但目前已发现,采用具有较大体积的取代环戊二烯做配体,如C_5Me_5H,C_5H_3〔Si(CH_3)_3〕_2H,C_5Me_4C_3H_7H和桥联的配体(C_5H_4)_2(CH_2)_3H_2都可得到相应的取代环戊二烯基轻希土氯化物。控制LnCl_3和CpNa的反应摩尔比也可以成功地得到这类轻希土的环戊二烯基氯化物。     

α''-取代磺酰基-α,β-不饱和酮的不对称催化环加成反应的研究

在手性金属钛配合物催化剂存在下，研究了α′－取代磺酰基－α，β－不饱和酮的不对称催化环加成反应；讨论了α，β－不饱和酮各种取代磺酰基对反应活性和对映选择性的影响；高收率地合成了高光学纯度的环加成产物，并对环加成产物的构型进行了鉴定。     

Solvation of acylium fragment ions in electrospray ionization quadrupole ion trap and Fourier transform ion cyclotron resonance mass spectrometry

In electrospray ionization (ESI) quadrupole ion trap and Fourier transform ion cyclotron resonance mass spectrometry, certain fragment ions (e.g. acylium ions) generated either during the ion transportation process (in the source interface region) or in the ion trap are found to undergo ion--molecule reactions with ESI solvent molecules (water, acetonitrile and aliphatic alcohols) to form adduct species. These unexpected solvated fragment ions severely complicate the interpretation of mass spectrometic data. High-resolution accurate mass measurements are important in establishing the elemental compositions of these adduct species and preventing erroneous data interpretation.     

Crystalline Morphology and Polymorphic Phase Transitions in Electrospun Nylon 6 Nanofibers

Uniform nylon 6 nanofibers with diameters around 200 nm were prepared by electrospinning. Polymorphic phase transitions and crystal orientation of nylon 6 in unconfined (i.e., as-electrospun) and a high T(g) (340 degrees C) polyimide confined nanofibers were studied. Similar to melt-spun nylon 6 fibers, electrospun nylon 6 nanofibers also exhibited predominant, meta-stable gamma crystalline form, and the gamma-crystal (chain) axes preferentially oriented parallel to the fiber axis. Upon annealing above 150 degrees C, gamma-form crystals gradually melted and recrystallized into the thermodynamically stable alpha-form crystals, which ultimately melted at 220 degrees C. Release of surface tension accompanied this melt-recrystallization process, as revealed by differential scanning calorimetry. For confined nanofibers, both the melt-recrystallization and surface tension release processes were substantially depressed; gamma-form crystals did not melt and recrystallize into alpha-form crystals until 210 degrees C, only 10 degrees C below the T(m) at 220 degrees C. After complete melting of nano-confined crystals at 240 degrees C and recrystallization at 100 degrees C, only alpha-form crystals oriented perpendicular to the nanofiber axis were obtained. In the polyimide-confined nanofibers, the Brill transition (from the monoclinic alpha-form to a high temperature monoclinic form) was observed at 180-190 degrees C, which was at least 20 degrees C higher than that in unconfined nylon 6 at approximately 160 degrees C. This, again, was attributed to the confinement effect.     

聚碳酸酯改性聚酯型热塑性聚氨酯弹性体的合成与性能

以聚碳酸１，６－已二醇酯（ＰＣ）、聚己二酸－１，４－丁二醇酯（ＰＢＡＧ）、４，４－二苯基甲烷二异氰酸酯（ＭＤＩ）和１，４－丁二醇（ＢＤＯ）为原料，合成线型聚碳酸酯改性聚酯型热塑性聚氨酯弹性体（ＴＰＣＺＥ）．对其玻璃化转变温度Ｔｇ、力学性能、耐水解性能和流变特性进行了研究。实验结果表明：随ＰＣ二醇含量的增加，弹性体的贮能模量下降，Ｔｇ则向高温方向（从－７．８℃到＋２．６℃）移动。水解后的强度保持率从８５．４％提高到９９，７％和１１７％，熔体的表现粘度降低，加工性能得到改善。     

快速气相色谱法测定食用油中的未衍生化长链脂肪酸

建立了利用短的微径色谱柱直接测定食用油中未衍生化长链脂肪酸的快速气相色谱方法。C12~C22脂肪酸在2 min之内实现基线分离，定量标准曲线的相关系数大于0.988，最低检测限（S/N=3）为2.80~9.60 mg/L,回收率为74.5%~86.5%。该方法快速、简便、准确，分析通量大，已成功地用于香油、色拉油及调和油等3种食用油中长链脂肪酸含量的测定。