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以含氟醇钾盐(NFHO-K )作为引发剂,通过阴离子活性聚合方法合成了氟烷基封端的聚甲基丙烯酸-2-(二甲氨基)乙酯-block-聚甲基丙烯酸-2-(二乙氨基)乙酯嵌段共聚物(NFHO-PDMA-b-PDEA).该共聚物与一般的含氟嵌段共聚物相比,既具有优良的表面活性,又具有较好的溶解性.通过对溶液表面张力的测定,荧光探针法对溶液临界聚集浓度(cac)的测定和透射电子显微镜(TEM)对共聚物在溶液中胶束形态的研究,发现无机盐对共聚物在水溶液中的聚集行为有明显的影响,并可以增强共聚物的表面活性. 相似文献
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以乙烯基二茂铁、丙烯酰胺和甲基丙烯酸二甲氨基乙酯为共聚单体,采用自由基聚合法合成了具有水溶性和氧化还原活性的聚合物,并通过示差扫描量热法、傅里叶红外光谱、紫外-可见吸收光谱,及电化学方法对其玻璃化转变温度、化学组成、质子化作用及电化学性能进行了分析。实验结果表明该共聚物为乙烯基二茂铁、丙烯酰胺和甲基丙烯酸二甲氨基乙酯三元共聚物。该共聚物具有较好的水溶性和柔性,这些特点有利于提高修饰电极电子转移的效率,以及实现酶活性中心与电极之间的直接电子转移。共聚物中的甲基丙烯酸二甲氨基乙酯结构单元在近中性的溶液中可发生质子化作用,可与酶之间形成离子键从而有利于缩短酶活性中心与电极表面之间导电路径。共聚物的电化学性能表现出良好的氧化还原可逆性,且实现了共聚物与电极之间的可逆电子转移。另外该共聚物在溶液中的扩散系数较低,有利于提高修饰电极的稳定性。 相似文献
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《高等学校化学学报》2015,(12)
采用连续投料法合成了两嵌段含糖聚合物——聚甲基丙烯酸葡萄糖氨基乙基酯-b-聚甲基丙烯酸-2-二甲氨基乙酯-co-甲基丙烯酸-2-二乙氨基乙酯(PGAMA-b-PDMAEMA-co-DEAEMA,PGME),并用核磁共振谱(1H NMR)和凝胶渗透色谱(GPC)确认了含糖聚合物PGME的化学组成及分子量.采用浊度法研究了含糖聚合物PGME与蛋白质的相互作用情况,通过改变环境p H值调控PGME对蛋白质的相互作用:当p H=8.3时,PGME只能与刀豆球蛋白A(Con A)结合,表现出PGME与Con A特异性结合的行为;而当p H=7.3时,PGME表现出与蛋白质的非特异性结合,说明通过改变环境p H值可调控PGME对蛋白质的相互作用.用动态光散射和原子力显微镜(AFM)表征了PGME水溶液聚集体. 相似文献
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以苄醇(BzOH)与氢化钾(KH)反应形成的氧阴离子作为引发剂, 依次引发甲基丙烯酸-2-(N,N-二甲氨基)乙酯(DMAEMA, 简称DMA)、甲基丙烯酸-2-(N,N-二乙氨基)乙酯(DEAEMA, 简称DEA)和甲基丙烯酸-(2,2,3,3,4,4,5,5-八氟)戊酯(OFPMA)进行氧阴离子聚合, 获得含氟三嵌段共聚物PDMA-b-PDEA-b-POFPMA和PDEA-b-PDMA-b-POFPMA. 共聚物的化学结构可以通过不同单体的加料顺序和各种单体的投料量加以控制. 通过1H NMR, 19F NMR和GPC测试, 研究聚合物的结构、分子量及分子量分布. 利用表面张力、荧光探针法、Zeta电位和透射电镜等测试方法, 研究共聚物在不同pH值的水溶液中的聚集行为. 相似文献
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采用粘度法、荧光探针和透射电镜研究了新型疏水缔合聚合物P(AM/POEA)和表面活性剂SDS和CTAB在水溶液中的相互作用. 聚合物P(AM/POEA)结构中, 疏水体(2-苯氧乙基丙烯酸酯)呈嵌段状无序地分布在聚丙烯酰胺主链上. 这类聚合物很容易和表面活性剂相互作用, 通过疏水缔合, 形成混合胶束状聚集体, 导致溶液粘度剧增. 随聚合物溶液中SDS的加入, 溶液粘度发生大幅度起伏变化, 出现最大值. 粘度最大值对应的表面活性剂浓度cS,max位于表面活性剂CMC附近, 并发现它的位置不随聚合物微结构而变化. 然而它们缔合作用的增粘程度却与聚合物疏水体含量XH及疏水嵌段尺寸NH有关. 在实验浓度范围内, XH和NH愈大, 溶液的粘度越高. 此外用透射电镜直接观察到聚合物/表面活性剂体系中聚集体的交联结构形貌. 相似文献
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通过甲基丙烯酸N,N-二甲氨基乙酯(dimethylamino ethyl methacrylate)和环己内酯(ε-caprolactone)之间的连续阴离子聚合, 合成了末端含有氨基的聚甲基丙烯酸N,N-二甲氨基乙酯-嵌段-聚己内酯的双亲性嵌段共聚物(PDMAEMA-b-PCL). 为了增强生物相容性, 通过末端氨基与D-葡萄糖酸内酯(D-gluconolactone)的酰胺化反应对该共聚物进行糖基修饰. 合成的共聚物的化学结构用氢核磁共振光谱(1H NMR)和红外光谱(IR)进行表征, 聚合物的分子量分布采用凝胶色谱(GPC)测定, 该嵌段共聚物在水溶液中的自组装行为则借助于动态光散射(DLS)进行了研究. 相似文献
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采用开环聚合(ROP)和原子转移自由基聚合(ATRP)的方法合成了具有多重敏感性的聚乙二醇单甲醚-聚己内酯-聚甲基丙烯酸二乙氨基乙酯(mPEG-b-PCL-b-PDEAEMA)三嵌段共聚物,利用傅里叶变换红外光谱(FTIR)、核磁共振(NMR)和凝胶渗透色谱(GPC)对嵌段共聚物的结构及分子量进行了表征,改变投料比可有效调控各嵌段长度,所得共聚物的分子量分布均保持在1.3左右;其自组装后改变体系的pH、温度和CO2加入量可以有效控制聚集体的粒径大小,随CO2加入量的增加,粒径由238nm增大到538nm,而通入N2后其粒径大小恢复原状;对聚集体进行载药性能研究,发现CO2的加入可提高载药量及包封率,在释放阶段降低体系的pH或通入CO2可增加药物的释放速率和释放量。 相似文献
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Block copolymers exhibit a different gas permeation behavior from that of homopolymers. In the diffusion process, the fraction of impermeable regions in the block copolymer decreases the diffusivity and the permeability. As the amount of impermeable regions in the block copolymer increases, the flow paths for the gas diffusion are restricted. Poly(amide-6-b-ethylene oxide) (PEBAX®) copolymer consists of a regular linear chain of rigid polyamide for hard segment interspaced with flexible polyether for soft segment. PEBAX® copolymer shows a typical permeation behavior of rubbery polymers. The permeability of CO2 increases with the pressure originating from the increment of the sorbed CO2 amounts. PEBAX® copolymer shows the high permeability and the high selectivity for polarizable/nonpolar gas pairs. Particularly, the selectivity of CO2 over N2 is 61 and that of SO2 over N2 is 500. For small and nonpolar gases (i.e. He, H2, O2 and N2), the permeability decreases with increasing the molecular size or volume of gases. On the other hand, for polarizable and larger gases (i.e. CO2 and SO2), it shows the high permeability. The high permeability and permselectivity of PEBAX® copolymer are attributed of polarizable gases to polyether segment in PEBAX®. 相似文献
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Hong-Yong Zhao Yi-Ming Cao Xiao-Li Ding Mei-Qing Zhou Quan Yuan 《Journal of membrane science》2008,310(1-2):365-373
A series of copolymers containing ether oxygen groups and amino groups were prepared based on N,N-dimethylaminoethyl methacrylate (DMEMA) and polyethylene glycol methyl ether methyl acrylate (PEGMEMA). The effect of PEGMEMA content in the copolymer on density, free volume, mechanical performance, and H2, CO2, N2 and CH4 gas transport properties of the copolymer was determined. Free volume was characterized using the polymer density and group contribution theory. The permeability of the copolymer to CO2 is high, and both the CO2/N2 and CO2/H2 selectivities are high. For example, the permeability coefficient of PDMAEMA–PEGMEMA-90 (“90” represents the weight percent of PEGMEMA) to CO2 is 112 Barrer and the CO2/N2 and CO2/H2 selectivity coefficients are 31 and 7, respectively. The effect of the temperature on gas transport properties was also determined. Finally, the potential application of the copolymer membranes for CO2/light gases separation was explored. 相似文献
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建立了基于自制全密闭进样系统的气相色谱-质谱测定全氟异丁腈(C4F7N)商品气中杂质的方法。待测气体在自制的密封系统内稀释并混合均匀,使用在线自动六通阀进样,采用Agilent GS-GASPRO色谱柱(30 m×0.32 mm×5μm)分离,测定了国内某公司(DC公司)和国外某公司(AC公司)的全氟异丁腈绝缘气体的杂质成分。结果表明,全氟异丁腈商品气中含有微量的N2、O2、C3HF7和痕量的C3F6,其中AC公司的C4F7N商品气体中的杂质总含量为0.13%, C4F7N纯度为99.87%; DC公司的C4F7N商品气体中的杂质总含量为0.83%, C4F7N纯度为99.17%,两家公司的C4F7 相似文献
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采用密度泛函理论(DFT)计算了MgAl-LDHs层板与无机阴离子(F-、Cl-、NO3-、CO32-、SO42-)和有机阴离子(水杨酸根离子([HO(C6H4)COO]-)、苯甲酸根离子([(C6H5)COO]-)、对二甲氨基苯甲酸根离子([p-(CH3)2N(C6H4)COO]-)、十二烷基磺酸根离子[C12H25SO3]-、己烷基磺酸根离子[C6H13SO3]-、丙烷基磺酸根离子[C3H7SO3]-)间的相互作用,获得稳定超分子几何结构及相互作用能。层板主体与客体间存在较强的超分子作用,包括主客体间静电作用和氢键等。主、客体间相互作用能数值大小顺序为CO32- > SO42- > F-> Cl-> NO3-;[p-(CH3)2N(C6H4)COO]-> [(C6H5)COO]-> [HO(C6H4)COO]-和[C12H25SO3]-> [C6H13SO3]- > [C3H7SO3]-。另外,还采用自然键轨道(NBO)计算和分析了LDHs 层板与阴离子间作用机理,从二阶微扰理论计算得到的稳定化能变化趋势与相互作用能数据基本吻合。 相似文献
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Alkylation of anions on solid inorganic supports : an interpretation of the function of the supports
In the anionic alkylation (CH3 CO2K + n C8 H17 Br) on solid inorganic supports, silica impregnated with cationic surfactant appears to be as effective as alumina, while silica bearing ammonium groups covalently bonded to the support (SPHEROSIL QMA) exhibits increased effectiveness. An interpretation based upon the superficial charge of the solid surfaces is proposed. 相似文献
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Fabio E. Malanca M. Burgos Paci Gustavo A. Argüello 《Journal of photochemistry and photobiology. A, Chemistry》2002,150(1-3):1-6
Photolyses of CF3C(O)X and C2F5C(O)X (X=Cl, F) at 254 nm in the presence of O2 yield the perfluorinated radicals C2F5O (C2) and CF3O (C1), respectively. The C2 radicals decompose to give CF3 radicals:which, in turn, react with O2 leading to the formation of C1 radicals. When in addition to O2, CO is present, the C1 radicals react with it leading to its catalytic oxidation to CO2. The trioxide CF3OC(O)O3C(O)OCF3 was observed following the photolysis of all four halides in the presence of O2 and CO.
C2F5O→CF3+CF2O
The other radical partners coming from the initial step in the photolysis (XC(O)) as well as the products of their reaction with O2 (XC(O)Oy, y=1, 2) do not react with CO but when X=F they lead to the formation of a new stable peroxy molecule with the formula CF3OC(O)O2C(O)F. Some of the properties of this new molecule, its stability and its IR features are presented in this work. 相似文献
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Olga V. Boltalina Lev N. Sidorov Ekaterina V. Sukhanova Igor D. Sorokin 《Chemical physics letters》1994,230(6):567-570
Difluorinated higher fullerenes have been studied by Knudsen cell mass spectrometry. Thermal negative ions CnF2− (n=60, 70, 72, 74, 76 and 78) were produced inside the effusion cell as well as the neutral molecules C60F2 and C70F2. From the equilibrium constants for the electron exchange reactions between difluorinated fullerenes and their parents electron affinity values were derived for C60F2 (2.74 eV) and C70F2 (2.80 eV). 相似文献
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Calvin K.W. Tse Anca Penciu Paula J. McInenly Kainthan R. Kumar Mark J. Drewitt Michael C. Baird 《European Polymer Journal》2004,40(12):2653-2657
The highly electrophilic borane B(C6F5)3 reacts with a variety of carboxylic acids RCO2H to form 1:1 and 1:2 adducts [RCO2H][B(C6F5)3] and [RCO2H][B(C6F5)3]2. These adducts exhibit enhanced acidities, and the 1:2 adduct of n-decanoic (stearic) acid in particular is an excellent initiator for the carbocationic polymerization of isobutene and copolymerization of isobutene with isoprene in methylene chloride and methyl chloride. High conversions to high molecular weight polyisobutene and isobutene-isoprene copolymers are obtained at unusually high temperatures, consistent with the anion [n-C17H35CO2 BC6F5)3 2]− being very weakly coordinating. Interestingly, the system also exhibits a surprising, as yet not understood, dependence of polymer molecular weights on the nature of R in methyl chloride. 相似文献
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H. J. Frohn A. Klose V. V. Bardin A. J. Kruppa T. V. Leshina 《Journal of fluorine chemistry》1995,70(2):147-154
Reactions of [C6F5Xe]+ [AsF6]− in acetonitrile with halide anions X− show different results depending on X. If X = I, Br or Cl, then C6F5X is obtained. If X = F, then C6F5H and C6F5---C6F5 are produced, and if X = HF2, then C6F6, C6F5H and C6F5---C6F5 are formed. 相似文献
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测定了在30℃、总离子强度为0.1m时不同比例混合的十烷基硫酸钠(C10SNa)-全氟辛酸钠(7CFNa)在四氯乙烯-水界面的界面张力,研究混合溶液的界面性质及胶团形成,结果表明:(1)7CFNa与C10SNa在混合溶液中,基本上各自独立形成胶团;(2)混合表面活性剂在四氯乙烯-水界面上的吸附与在正庚烷-水界面上吸附规律相同;(3)测定C10SNa、7CFNa在不同油-水界面上的界面张力,证实碳氟链与碳氯链之间具有“互憎性”。 相似文献