Preparation and properties of polyurethane networks based on α,ω-difunctional poly(hexafluoropropylene oxide)

Poly(hexafluoropropylene oxide), poly(HFPO), networks were prepared from functional polymers by end linking via urethane groups. The prepolymers were characterized by NMR spectroscopy and GPC. The networks were characterized by determination of the number of network chains from the shear modulus, and were snown to contain both trifunctional crosslinks and difunctional links. The properties of the networks were investigated by a range of techniques. Compared with fully-fluorinated networks formed via triazine cross-links, investigated previously, the urethane-linked networks were more readily prepared but were poorer elastomers, were less thermally stable, and were less resistant to swelling by common polar solvents. © 1995 John Wiley & Sons, Inc.     

Synthesis, properties, and applications of urethane-modified acrylated poly(ester-amide)s

Epoxy resin-based unsaturated poly(ester-amide) resins (UPEAs) were treated with acryloyl chloride to afford acrylated UPEAs resins (AUPEAs). Urethane-based acrylated poly(ester-amide)s prepared by reaction with diisocyanate were characterized by elemental analysis, by molecular weight determination (by vapour pressure osmometry), by IR spectral study, and by thermogravimetry. The curing of interacting blends was monitored by differential scanning calorimetry (DSC). On the basis of DSC data in-situ glass-reinforced composites were prepared from the resulting materials and their mechanical, electrical, and chemical properties were characterized. Unreinforced blends were characterized by thermogravimetry.     

Method extension study to validate applicability of AOAC Official Method 996.14 Assurance polyclonal enzyme immunoassay for detection of Listeria monocytogenes and related Listeria spp. from environmental surfaces: collaborative study

Test portions from 3 environmental surface types, representative of typical surfaces found in a food production facility, were analyzed by the Assurance Listeria Polyclonal Enzyme Immunoassay (EIA) and the U.S. Department of Agriculture/Food Safety and Inspection Service (USDA/FSIS) culture method for Listeria monocytogenes and related Listeria species. In all cases, naturally contaminated environmental test samples were collected from an actual food production facility by sponge or swab. Test samples from concrete surfaces were collected by both swab and sponge; sponge test samples were collected from rubber surfaces, and swabs were used to sample steel surfaces. Test portions from each surface type were simultaneously analyzed by both methods. A total of 23 collaborators, representing government agencies, as well as private industry in both the United States and Canada, participated in the study. During this study, a total of 550 test portions and controls was analyzed and confirmed, of which 207 were positive and 336 were negative by both methods. Six test portions were positive by culture, but negative by the EIA. Three test portions were negative by culture, but positive by the EIA. Two test portions were negative by EIA and by culture, but confirmed positive when EIA enrichment broths were subcultured to selective agars. The data reported here indicate that the Assurance Listeria EIA method and the USDA/FSIS culture method are statistically equivalent for detection of L. monocytogenes and related Listeria species from environmental surfaces taken by sponges or swabs.     

Method extension study to validate applicability of AOAC Official Method 997.03 visual immunoprecipitate assay (VIP) for Listeria monocytogenes and related Listeria spp. from environmental surfaces: collaborative study

Test portions from 3 environmental surface types, representative of typical surfaces found in a food production facility, were analyzed by the Visual Immunoprecipitate assay (VIP) and the U.S. Department of Agriculture/Food Safety and Inspection Service (USDA/FSIS) culture method for Listeria monocytogenes and related Listeria species. In all cases, naturally contaminated environmental test samples were collected from an actual food production facility by sponge or swab. Test samples from concrete surfaces were collected by both swab and sponge; sponge test samples were collected from rubber surfaces, and swabs were used to sample steel surfaces. Test portions from each surface type were simultaneously analyzed by both methods. A total of 27 laboratories, representing government agencies as well as private industry in both the United States and Canada, participated in the study. During this study, a total of 615 test portions and controls was analyzed and confirmed, of which 227 were positive and 378 were negative by both methods. Nine test portions were positive by culture, but negative by the VIP. Five test portions were negative by culture, but positive by the VIP. Four test portions were negative by VIP and by culture, but confirmed positive when VIP enrichment broths were subcultured to selective agars. The data reported here indicate that the VIP method and the USDA/FSIS culture method are statistically equivalent for detection of L. monocytogenes and related Listeria species from environmental surfaces taken by sponges or swabs.     

系列甘露糖醛酸寡糖的制备与鉴定

用酸降解法制备了系列甘露糖醛酸寡糖(聚合度2～8),并分析测定了寡糖的结构. 褐藻胶经部分酸水解,于pH=2.85处分级获得聚甘露糖醛酸. 继续用酸降解法降解聚甘露糖醛酸,经凝胶柱层析分离纯化,获得系列甘露糖醛酸寡糖. 用荧光标记糖电泳(FACE)对寡糖进行了分析,并用电喷雾离子化质谱(ESI-MS)、 核磁共振波谱(NMR)及红外光谱(FTIR)进行了结构表征. 本研究用酸降解法制备饱和甘露糖醛酸寡糖,用凝胶柱层析法分离获得系列聚合度的寡糖,为褐藻胶大分子构效关系研究和药物的筛选与发现提供了重要的基础资料.     

Kinetics and thermodynamics of the adsorption of some dyestuffs and p-nitrophenol by chitosan and MCM-chitosan from aqueous solution

The effect of initial concentration, temperature, and shaking rate on the adsorption of three dyestuffs [orange II (O-II), crystal violet (CV), and reactive blue 5 (RB5)] and an ideal adsorbate, p-nitrophenol (PNP), by chitosan (Sigma C-3646) and the effect of temperature on the adsorption of O-II and CV by monocarboxymethylated chitosan (MCM-chitosan) were investigated. Kinetic data obtained for the adsorption of each dyestuff and PNP by chitosan and of O-II and CV by MCM-chitosan at different temperatures were applied to the Lagergren equation, and adsorption rate constants (k(ads)) at these temperatures were determined. These rate constants related to the adsorption of O-II and RB5 by chitosan and of O-II by MCM-chitosan were applied to the Arrhenius equation, and activation energies (E(a)) were determined. In addition, the isotherms for adsorption, at different temperatures, of each dyestuff and PNP by chitosan and of O-II and CV by MCM-chitosan were also determined. These isothermal data were applied to linear forms of isotherm equations that they fit, and isotherm constants were calculated. Because the isotherm curves obtained for the adsorption of O-II and CV by chitosan and of CV by MCM-chitosan fit the Langmuir adsorption isotherm, b constants were applied to thermodynamic equations, and thermodynamic parameters (delta G, delta H, and delta S) were calculated. Lastly, chitosan and MCM-chitosan were compared with respect to the ability to take up the dyestuffs and PNP.     

Novel structural derivatives of poly-p-phenylenevinylene

Blends of oligoarylenevinylenes were prepared with polycarbonate, resp. polystyrene. These blends were investigated by electron microscopy as well as by differential scanning calorimetry (DSC) measurements. Block copolymers with well defined arylenevinylene segments were prepared by polycondensation of OH-functionalized oligoarylenevinylenes and aliphatic biscarboxylic acid chlorides. Arylenevinylene functionalized polystyrenes were prepared by Pd-catalyzed coupling reactions.     

Polybenzimidazoles containing anthracene photodimer

Polybenzimidazoles that contained anthracene photodimer were prepared. The molecular weights of the polymers prepared by the photopolymerization of bis-anthrylbenzimidazoles were limited by the precipitation of the resulting polymers from the reaction organic solvents. Higher molecular weight polymers were obtained by the photopolymerization of bis-anthryl-Schiff's bases, followed by the oxidation of the resulting polymers. These polymers were soluble in acidic solvents such as formic and sulfuric acids but were insoluble in organic solvents.     

CO2加氢合成二甲醚的催化剂的制备

先采用均匀沉淀法制备出CuO—ZnO催化剂,然后以CuO—ZnO催化剂作为晶核采用水热合成法制备出CuO—ZnO／HZSM-5（氢型ZSM-5分子筛）复合催化剂．利用X射线衍射和氨程序升温脱附手段对复合催化剂进行表征,并应用于CO2催化加氢合成二甲醚的反应．研究结果表明,在相同的反应条件下,这种CuO—ZnO／HZSM-5复合催化剂与采用物理混合法制备出的复合催化剂相比具有更好的催化效果,不但提高了CO2的转化率、二甲醚的选择性以及二甲醚和甲醇的总选择性,同时还改善了催化剂的稳定性．     

分子三维投影法在苯酚类化合物构效关系研究中的应用

对苯酚类化合物进行三维投影得到了5个形状参数,将其与3个Am指数及8个量子化学参数相结合.由最佳变量子集回归法对变量进行了压缩与选择,运用多元回归分析和人工神经网络法分别构造了预测数学模型,得到了满意的结果.     

Amino acids and peptides. LV. Application of 2-adamantyl derivatives as protecting groups to the synthesis of peptide fragments related to Sulfolobus solifataricus ribonuclease. II.

Segment condensations were performed to construct peptide fragments related to Sulfolobus solifataricus Ribonuclease. At each condensation step, the new protecting groups were stable. The protected peptide fragments were treated with a low-high HF procedure to give the desired peptide fragments. These peptide fragments were also prepared by the solid-phase method, and the obtained peptides were compared with those obtained by the solution method. The peptide fragments obtained by the solution method were identical with those obtained by the solid-phase method on analytical HPLC, indicating that the new protecting groups could be easily removed by HF, and no racemization occurred during the synthesis of the protected peptides.     

苯丙烯类葡萄糖氧苷的合成及其抗缺氧活性

以取代苯甲醛(1a~1t)为原料,通过Knoevenagel缩合、酯化和LiAlH₄还原等反应制得苯丙烯醇衍生物(3a~3t);以取代肉桂醛(1u~1x)为原料,经NaBH₄还原制得苯丙烯醇衍生物(3u~3x); 3a~3x与全乙酰化溴代葡萄糖经Koenigs-Knorr偶联反应及MeONa/MeOH体系脱除乙酰保护基反应,合成了24个苯丙烯类葡萄糖氧苷(5a~5x),其中5c,5f ~ 5x为新化合物,其结构经¹H NMR和ESI-MS表征。采用MTT法测定了5对缺氧损伤的内皮细胞(EA.hy926)的抗缺氧活性。实验结果表明： 5b, 5e, 5g, 5p, 5q, 5s, 5t和5y对EA.hy926的抗缺氧活性均高于经景天苷。     

锂离子电池纳米N iO负极材料的研究

分别应用溶胶凝胶法和室温固相法合成纳米N iO材料,运用DSC、TG等热分析技术分析了合成的样品,通过选择不同的溶剂和调节溶液的pH值,优化溶胶凝胶法合成纳米N iO负极材料.XRD、TEM技术表征材料的结构和形貌,并对所得材料作了电化学性能测试.     

Rigid-rod polymers with polysiloxane side chains. I. Synthesis and characterization of rigid-rod polyimides with polysiloxane side chains and their compatibility with linear polysiloxanes

Rigid-rod aromatic polyimdies having polydimethylsiloxane side chains were prepared for the purpose of dispersing rigid-rod molecules in silicone matrices for molecular reinforcement. The polyimides were obtained by imidizing the polyamide-acids bearing the side chains either thermally or chemically, which were synthesized by reacting 4,4′-diaminobiphenyl-terminated polysiloxane macromonomers with pyromellitic dianhydride in THF. The polyamide-acid films obtained by removing the solvent were soluble in THF, but the polyimides were insoluble in any common solvent. The polyimides showed no melting transition below 350°C on DSC analysis, at which temperature the side chain started decomposing. Although all the polyimides were anisotropic as observed by a polarizing microscope, x-ray diffraction analysis suggested the presence of only limited chain organization. Blends with linear polydimethylsiloxanes were prepared by casting the THF solution containing the polyamide-acid and the polydimethylsiloxane, followed by solvent evaporation and thermal imidization. With relatively longer side chains, the polyimides were proved to be compatibilized with polydimethylsiloxanes. © 1994 John Wiley & Sons, Inc.     

含羧甲磺酰基水暂溶性分散染料的研究──几个中间体及染料的合成

用氯磺化法或硫醚氧化法结合成出８个中间体，并以其作为重氮组分，合成出１０个新的含羧甲磺酰基水暂溶性分散染料。     

电感耦合等离子体原子发射光谱法(ICP-AES)测定铜磁铁矿中铜、锰、铝、钙、镁、钛和磷的含量

通过样品处理、干扰实验、方法检出限、准确度和精密度实验,确定了最佳实验条件,建立了电感耦合等离子体-原子发射光谱法(ICP-AES)测定铜磁铁矿中铜、锰、铝、钙、镁、钛和磷含量的方法。试料经盐酸、硝酸、氢氟酸、高氯酸分解,用盐酸溶解盐类,过滤,采用电感耦合等离子体原子发射光谱法同时测定滤液中铜、锰、铝、钙、镁、钛和磷的含量。方法检出限为锰、钛和磷小于0.00085%,其它元素小于0.0054%,分析结果与分光光度法、X射线荧光光谱法(XRF)和原子吸收光谱法(AAS)分析结果一致,8个实验室对5个水平样品进行协同实验给出了方法的精密度。     

Two Energetic Ionic Salts of en·PA·H2O and en·TNR: Preparation,Structural Characterization,and Properties

Energetic salts of en · PA · H₂O and en · TNR were synthesized by using ethylenediamine and picric acid (PA) or 2,4,6‐trinitroresorcinol (TNR) as raw materials, and their structures were characterized by elemental analysis and FT‐IR spectroscopy. Single crystals of the title salts were obtained and their structures were determined by single‐crystal X‐ray diffraction. The thermal decomposition behaviors were investigated by DSC and TG‐DTG technologies, furthermore the non‐isothermal kinetic parameters and enthalpies of formation for the salts were calculated. Their combustion heats were measured by oxygen bomb calorimetry and their enthalpies of formation were also calculated based on the combustion heat data. In addition, the detonation pressure (P) and detonation velocities (D) of the salts were predicted by using the K‐J equations. The results indicated that the title salts have potential applications in the field of energetic materials.     

新型取代苯甲胺葡萄糖氮苷的合成及其抗缺氧活性

以取代苯甲醛(1a~1s)为原料,通过三条路线［A:1a~1o为起始原料,经硼氢化钠还原和溴代反应制得苄基溴衍生物(3a~3o); 3a~3f与邻苯丁二酰亚胺经Gabriel反应制得N-苯甲基邻苯丁二酰亚胺衍生物(4a~4f); 4a~4f与水合肼反应后与D-吡喃葡萄糖反应合成了N-β-D吡喃葡萄糖苯甲胺类化合物(6a~6f)。 B: 3g~3o与全乙酰化D-吡喃葡萄糖胺反应制得全乙酰化葡萄糖氮苷5g~5o; 5g~5o在MeONa-MeOH中脱除乙酰基合成了6g~6o。 C: 1p~1s与全乙酰化D-吡喃葡萄糖胺反应制得全乙酰化葡萄糖氮苷5p~5s; 5p~5s经MeONa-MeOH脱除乙酰基合成了6p~6s］合成了19个取代苯甲胺N-β-D吡喃葡萄糖氮苷类似物(6a~6s,其中6a, 6b, 6e, 6f, 6j, 6n~6q, 6s为新化合物),其结构经¹H NMR和ESI-MS表征。采用MTT法研究了6a~6s对缺氧内皮细胞代谢活力的影响。结果表明： 6a, 6g, 6h和6l的抗缺氧活性优于红景天苷。     

Preparation and Characterization of Nano-Structured SiO2 Thin Films on Carbon Steel

Nano-structured SiO2 thin films were prepared on the surface of carbon steel for the first time by LPD. The compositions of the films were analyzed by XPS, and the surface morphology of the thin films were observed by AFM. The thin films were constituted by compact particles of SiO2, and there was no Fe in the films. In the process of film forming, the SiO2 colloid particles were deposited or absorbed directly onto the surface of carbon steel substrates that were activated by acid solution containing inhibitor, and corrosion of the substrates was avoided. The nano-structured SiO2 thin films that were prepared had excellent protective efficiency to the carbon.     

有机溶剂热生长技术制备硫族化合物及其光学特性的研究

以有机溶剂热生长技术(solvothermaltechnique)制备了半导体硫族化合物(CdS、ZnS、MoS₂)等纳米颗粒,采用XRD、TEM等技术对其结构进行表征.以ITO导电玻璃以及导电聚合物(PANI、PPY)膜为基底,将纳米颗粒涂布其上并以PL法研究其光学特性,实验结果表明:经修饰后,材料的荧光发射位置发生显著的变化.