孪尾疏水缔合水溶性共聚物聚(丙烯酰胺/丙烯酸钠/N,N-二己基丙烯酰胺)/十二烷基硫酸钠水溶液的粘度行为

水溶性三元共聚物;孪尾疏水缔合水溶性共聚物聚(丙烯酰胺/丙烯酸钠/N;N-二己基丙烯酰胺)/十二烷基硫酸钠水溶液的粘度行为     

含孪尾型丙烯酰胺的HAPAM在新胶束聚合体系中的制备及其疏水缔合性

以表面活性单体2-丙烯酰胺基十二烷磺酸钠(NaAMC12S)为表面活性剂构建了新的胶束共聚合体系,实施了丙烯酰胺(AM)与N,N-二正十二烷基丙烯酰胺(DiC12AM)的胶束共聚合,制备了含孪尾型丙烯酰胺的疏水缔合聚丙烯酰胺(HAPAM),该聚合物为三元共聚物DiC12AM/NaAMC12S/AM.通过控制共聚合条件,制得了微结构系列变化的共聚物;采用红外光谱法表征了三元共聚物的化学结构,用荧光探针法与表观粘度法重点研究了共聚物DiC12AM/NaAMC12S/AM的大分子链微结构与其疏水缔合性的关系.结果表明:新胶束共聚合体系大大简化了胶束的共聚合操作,而且由于表面活性单体进入共聚物主链,使三元共聚物DiC12AM/NaAMC12S/AM具有更强的疏水缔合性.与由单尾型丙烯酰胺N-正十二烷基丙烯酰胺(C12AM)为疏水单体制备的HAPAM相比,由DiC12AM制得的HAPAM疏水缔合性更为显著.     

聚(丙烯酰胺/丙烯酸钠/N,N-二辛基丙烯酰胺)与表面活性剂的相互作用

利用粘度法研究了孪尾疏水缔合水溶性聚(丙烯酰胺/丙烯酸钠/N,N-二辛基丙烯酰胺)[P(AM/NaAA/D iC8AM)]与表面活性剂十二烷基硫酸钠(SDS)、十六烷基三甲基溴化铵(CTAB)、壬基酚聚氧乙烯醚(OP-10)的相互作用。研究表明SDS、CTAB的加入,能显著地降低P(AM/NaAA/D iC8AM)水溶液的临界缔合浓度。表明P(AM/NaAA/D iC8AM)与SDS、CTAB的疏水缔合作用较强,而与OP-10的疏水缔合作用较弱。     

孪尾疏水单体N,N-二正辛基丙烯酰胺的合成与表征

利用二正辛胺与丙烯酰氯非均相胺解法合成了孪尾疏水单体N,N-二正辛基丙烯酰胺,其结构经1H NMR,IR和元素分析表征。考察了搅拌方式和反应时间对产率的影响,结果表明,搅拌越剧烈、反应时间越长产率越高。在0℃~10℃下,反应6 h,产率可达89.49%。     

改性聚丙烯酰胺水溶液的疏水缔合性质

合成了一种疏水缔合水溶性聚丙烯酰胺共聚物,使用荧光光谱法并结合紫外及流变性实验,对制备的疏水缔合水溶性聚丙烯酰胺共聚物在水溶液中形成疏水微区、超分子聚集体及空间网络结构进行了研究,并用扫描电子显微镜证实了溶液中网络结构的存在.     

含氟疏水缔合聚丙烯酰胺的制备及溶液性质研究

以异佛尔酮二异氰酸酯(IPDI)、四氟丙醇(FOH)和烯丙基聚乙二醇(APEG1200)为原料合成了含氟表面活性单体(FSM),并以FSM为疏水单体,在它的胶束溶液中实现了其与丙烯酰胺(AM)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS)的水溶液共聚合,制备出含氟疏水缔合聚丙烯酰胺(FAPAM)。采用流变仪研究了FAPAM水溶液的疏水缔合性能,并考察了盐、剪切率和温度对FAPAM缔合性能的影响。结果表明,FAPAM水溶液的疏水缔合性能受FSM含量的影响,具有一定的耐盐性。FAPAM属于假塑性体系,表现出较强的抗剪切性能。适当升高温度对FAPAM水溶液的疏水缔合有一定的促进作用。     

疏水缔合聚丙烯酰胺的合成及溶液性能研究

水溶性疏水缔合聚合物是在聚合物亲水主链上引入极少量疏水基团(一般小于2ｍｏｌ%)而形成的一种新型水溶性聚合物[1]。由于这类聚合物具有独特的流变性能,因而备受学术界和工业界关注。目前已作为涂料增稠剂[2]和流变改性剂[3]得到了应用,而通过在部分水解聚丙烯酰胺(ＨＰＡＭ)的亲水主链上引入少量疏水单体而形成的疏水缔合聚丙烯酰胺(ＨＡＰＡＭ)则可望克服ＨＰＡＭ耐温、耐盐性差的缺陷[4]而作为新一代水溶性聚合物材料用于油气开采作业[5,6]。由于亲水单体和疏水单体的不相容性,通常通过在反应溶液中加入表面活性剂使亲水单体和疏水单体…     

表面活性单体NaAMC_(14)S/丙烯酰胺共聚物的分子链微结构与疏水缔合性

在实施丙烯酰胺型阴离子表面活性单体2-丙烯酰胺基十四烷磺酸钠(NaAMC14S)与丙烯酰胺(AM)水溶液均相共聚合过程中,分别通过改变AM与NaAMC14S的投料比、改变外加电解质NaCl的加入量以及引发剂的用量,制备了分子链微结构系列变化的具有微嵌段结构的共聚物NaAMC14S/AM;采用荧光探针法与表观粘度法研究了共聚物分子链微结构与其疏水缔合性能之间关系,探索了共聚物分子链中疏水微嵌段含量、疏水微嵌段长度及共聚物分子量诸微结构因数对共聚物疏水缔合性的影响.结果表明,共聚物NaAMC14S/AM的疏水缔合性随着疏水微嵌段含量的增加而增强,随着疏水微嵌段长度的增长而增强,当疏水微嵌段含量和嵌段长度一定时,共聚物的疏水缔合性随分子量的增大而增强.     

疏水缔合聚丙烯酰胺在表面活性单体胶束溶液中的制备及其流变特性

配制了表面活性单体2-丙烯酰胺基十二烷磺酸钠(NaAMC12S)与十二烷基硫酸钠(SDS)的胶束溶液,分别测定了强疏水单体N-正十二烷基丙烯酰胺(C12AM)在两种胶束溶液中的增溶性能;在此基础上,于两种胶束溶液中分别进行了丙烯酰胺(AM)与C12AM的胶束共聚合,制备了疏水缔合聚丙烯酰胺(HAPAM),它们分别为二元共聚物C12AM/AM与三元共聚物C12AM/NaAMC12S/AM;测定了两种共聚物的红外光谱;采用荧光探针法与表观粘度法重点研究了它们的疏水缔合性与流变性能.结果表明,在表面活性单体NaAMC12S的胶束溶液中,可顺利地实现AM与疏水单体的胶束共聚合,由于表面活性单体也参与了共聚合,故制得的产物为三元共聚物C12AM/NaAMC12S/AM;与在SDS胶束溶液中制备的二元共聚物C12AM/AM相比,前者的疏水缔合性更强,其强疏水缔合性以强疏水单体C12AM的贡献为主,以表面活性单体NaAMC12S的贡献为辅.     

疏水缔合聚丙烯酰胺的合成和表征的研究进展

论文综述了疏水缔合聚丙烯酰胺(HAPAM)的合成方法,包括共聚合法和化学改性法。共聚法主要包括非均相共聚法,均相共聚法,反相(微)乳液聚合法,胶束共聚合法,模板聚合法,无皂乳液聚合法,活性阴离子聚合法,超临界CO2介质法。此外,论文还对HAPAM的表征方法进行了综述,并对HAPAM的合成和表征方面的发展前景进行了展望。     

Solvent extraction separation of In/III/-Tl/III/ and Hg/II/-Cd/II/-Co/II/ with sulphoxides

Solvent extraction studies have been made on some metals: In/III/-Tl/III/ and Hg/II/-Cd/II/-Co/II/, from ammonium thiocyanate solutions by dialkyl sulphoxides. Separation of these metals from one another can be achieved by suitable choice of the extracted conditions. The nature of the extractable metal species has been elucidated.     

Synthesis of chlorobis/β-diketonato/oxotechnetium/V/ and tris/β-diketonato/technetium/III/ complexes

Chlorobis/-diketonato/ oxotechnetium/V/ complexes [TcOCl/-dik/₂, -diketone=acetylacetone, benzoylacetone and dibenzoylmethane] were newly synthesized using macroamount of⁹⁹Tc. These complexes were further separated into geometrical isomers. Furthermore, an improvement of the yields for the syntheses of tris/-dike-tonato/technetium/III/ complexes [Tc/-dik/₃, -diketone=acetylacetone, benzoylacetone and 2-thenoyltrifluoroacetone] was examined using Tc/III/-thiourea complexes as a starting material.     

Direct synthesis of dimethyl carbonate ?from CH3OH AND CO2 by H3PW12O40/CexTi1-xO2 catalyst

Summary Ce_xTi_1-xO₂ and H₃PW₁₂O₄₀/Ce_xTi_1-xO₂ catalysts were prepared using a sol-gel method, and applied to the direct synthesis of dimethyl carbonate from methanol and carbon dioxide. H₃PW₁₂O₄₀/Ce_xTi_1-xO₂ showed a better catalytic performance than the corresponding Ce_xTi_1-xO₂, due to the bifunctional catalysis of Br?nsted acid sites (provided by H₃PW₁₂O₄₀) and base sites (provided by Ce_xTi_1-xO₂). H₃PW₁₂O₄₀/Ce_0.1Ti_0.9O₂ showed the highest catalytic performance among the H₃PW₁₂O₄₀/Ce_xTi_1-xO₂ catalysts.     

Simultaneous propane dehydrogenation andco2hydrogenation overCrOx/SiO2catalyst

Summary Single reverse water-gas shift (RWGS) and dehydrogenation of propane with CO₂(DH-CO₂) reactions in the presence and absence of the CrO_x/SiO₂ catalyst have been studied between 673 and 873 K. It was found that the CrO_x/SiO₂ catalyst is active both in the dehydrogenation of propane and in the RWGS reactions. The obtained results suggest that the dehydrogenation of propane to propene in the presence of CO₂on CrO_x/SiO₂can be facilitated by the RWGS reaction.</o:p>     

Crystal structure of Na3PO4 · 12H2O

The crystal structure of trisodium monophosphate hemihydrate was determined. The space group is $\text{C2}\text{c}$ and a unit cell contains eight formula units. The unit cell dimensions of $\text{Na}{}_3\text{PO}{}_4\text{·}\text{1}\text{2}\text{H}{}_2\text{O}$ are a = 9.631(3), b = 5.416(2), c = 16.938(8) Å, β = 102.60(5)°. The final R value is 0.027 for a set of 1430 independent reflections. This atomic arrangement is mainly a three-dimensional network of distorted NaO₆ octahedra. The hydrogen bonding scheme is given.     

LixNi0.8-yCo0.2ZnyOp的合成及电化学性能研究

A series of single-phase Li_xNi_0.8-yCo_0.2Zn_yO_p(0.96 ≤x≤ 1.10， 0 ≤y≤ 0.05， 2 ≤p≤ 2(1+y) ) (different in the y values) were synthesized by a two-step solid state reaction method， in which LiOH·H₂O， Zn-doped spherical Ni(OH)₂ and Co₂O₃ were used as the precursors. The ICP-AES analyses proved that the Zn-doped compounds synthesized had the nonstoichiometric form. The results of the XRD， SEM identified that the uniform particles of the as-prepared materials having a good layered structure were fine， narrowly distributed and well crystallized. The electrochemical performance test was carried out and the results showed that the as-prepared Zn-doped materials had not only a high capacity， but also a better cycling stability characterization than the un-doped one. The Li_1.06Ni_0.75Co_0.22Zn_0.03O_2.03 material has an initial reversible capacity as high as 160.5mAh·g^-1; and a first discharge efficiency 89.2%， and exhibits satisfactory cyclic stability with 90% retainable capacity after 50 cycles.     

An investigation of the promotional effect of propylene or propane traces on the activity of sulfatedPt/g-Al2O3andPt-Sn/g-Al2O3inCH4combustion

Summary A strong promoting effect of the presence of C₃H₈or C₃H₆was determined for the combustion of CH₄in excess oxygen, over pre-sulfated 1%Pt/g-Al₂O₃and pre-sulfated 1%Pt-2%Sn/g-Al₂O₃catalysts.</o:p>     

Synthesis and characterization of Ti1−2xNbxNixO2−x/2 solid solutions

Doped-rutile has been traditionally used in ceramic pigments for its intense optical properties. In this paper, we compare the classical ceramic synthesis of Ti_1−2xNb_xNi_xO_2−x/2 system with the sol-gel methodology, which allows a reduction of the anatase-rutile transformation temperature. The composition was optimised in order to obtain a unique rutile phase with the minimum amount of pollutant Ni(II) and enhanced chromatic coordinates. Incorporation of the doping ions in the rutile structure was corroborated by XRD and Rietveld refinements. The species responsible for the colour mechanism were studied by different techniques. UV-VIS spectroscopy showed the characteristic features of Ni²⁺ ions, whose existence was corroborated by EPR and magnetic measurements. From these results, (Ni,Nb)doped-TiO₂ powder samples can be now shaped as thin films, monoliths, etc. by using sol-gel methodology without modifying their properties. This study introduces new possibilities of coloured TiO₂-based solid solutions in new combined advanced applications (colouring agent and photocatalyst, etc.).     

Visible light-sensitive yellow TiO2−xNx and Fe-N co-doped Ti1−yFeyO2−xNx anatase photocatalysts

Nitrogen substituted yellow colored anatase TiO_2−xN_x and Fe-N co-doped Ti_1−yFe_yO_2−xN_x have been easily synthesized by novel hydrazine method. White anatase TiO_2−δ and N/Fe-N-doped samples are semiconducting and the presence of ESR signals at g ∼1.994-2.0025 supports the oxygen vacancy and g∼4.3 indicates Fe³⁺ in the lattice. TiO_2−xN_x has higher conductivity than TiO_2−x and Fe/Fe-N-doped anatase and the UV absorption edge of white TiO_2−x extends in the visible region in N, Fe and Fe-N co-doped TiO₂, which show, respectively, two band gaps at ∼3.25/2.63, ∼3.31/2.44 and 2.8/2.44 eV. An activation energy of ∼1.8 eV is observed in Arrhenius log resistivity vs. 1/T plots for all samples. All TiO₂ and Fe-doped TiO₂ show low 2-propanol photodegradation activity but have significant NO photodestruction capability, both in UV and visible regions, while standard Degussa P-25 is incapable in destroying NO in the visible region The mid-gap levels that these N and Fe-N-doped TiO₂ consist may cause this discrepancy in their photocatalytic activities.     

LixZryOz三元化合物的制备及表征

采用高温固相法制备了4种高纯度晶相组成的LixZryOz三元化合物,研究了焙烧温度、时间、反应物的种类和初始反应物物质的量比对产物组成的影响,进一步用XRD、SEM及BET分析方法对产物的晶相结构、表面形貌及比表面积进行了表征.实验结果表明,Li2CO3与ZrO2在适当条件下可以合成得到单斜相Li3ZrO3;以LiOH替代Li2CO3,在适当条件下可以分别合成得到四方相Li2ZrO3和三斜/单斜相Li6Zr2O7;进一步以Zr(NO3)4·5H2O代替Zr02,可将单斜相Li6Zr2O7的制备时间由96 h缩短至24 h.SEM照片显示产物硬团聚明显,粒径分布在1～10μm间,BET分析表明样品比表面积处于1.0～9.0 m2·g-1间分布,反应过程中锂的过量以及长时间高温焙烧是引起产物粒径长大和产生硬团聚的主要原因.