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1.
通过静电纺丝方法制备了掺杂离子液体([BMIM][PF_6])的聚偏氟乙烯(PVDF)纳米纤维.研究结果表明,[BMIM][PF_6]与PVDF具有相互作用,并可促进PVDF形成β相晶体.在溶剂挥发后,离子液体存在于PVDF纳米纤维的表面.纳米纤维中的离子液体含量对复合纳米纤维的表面形态和润湿性具有显著影响.通过离子液体的引入,可有效推迟水滴在纳米纤维表面的结冰时间,降低水滴的结晶温度,并且降低冰黏附强度.研究结果显示含有10%[BMIM][PF_6]的PVDF纳米纤维疏水性最高,并具有优异的防结冰性质.  相似文献   

2.
室温离子液体由于其极低的蒸汽压、比较好的热稳定性和化学稳定性、良好的分子结构与性能的可设计性等优点,作为一种新型的环境友好溶剂在很多领域有着广泛的应用.对于离子液体的微观结构和微观性能的研究是设计新型离子液体以及扩展离子液体应用的关键.本文通过荧光探针分子香豆素153(C153)的转动动力学和对微观环境敏感的荧光探针分子1, 3-二(1-芘基)丙烷(BPP)的稳态荧光光谱,探测和表征了烷基取代的离子液体1-丁基-3-甲基咪唑六氟磷酸盐([bmim][PF6])和与其具有相似结构的醚键官能化的离子液体1-甲氧基乙基-3-甲基咪唑六氟磷酸盐([moemim][PF6])的微观结构和微粘度. C153探针分子在离子液体[bmim][PF6]中的转动过程具有快、慢两个组分表明离子液体[bmim][PF6]内部存在松散和紧密的两种结构微区;而C153探针分子在离子液体[moemim][PF6]中的转动动力学只存在一种过程,说明醚键的引入使得[moemim][PF6]内部趋于一种类型的微环境.通过C153探针分子的转动时间研究发现,醚键官能化的离子液体[moemim][PF6]的微粘度小于烷基链取代的离子液体[bmim][PF6],同时通过BPP探针分子的二聚体激基复合物(excimer)与单体(monomer)荧光发射强度的比值(IE/IM)研究也证明这一结果.醚键的引入使得离子液体[moemim][PF6]相对于离子液体[bmim][PF6],侧链的极性更大、柔顺性更好,同时醚键有可能作为氢键的受体与阳离子形成氢键从而削弱离子液体中阴、阳离子间的相互作用,使得离子液体[moemim][PF6]的微观环境比离子液体[bmim][PF6]更为均一,同时具有更小的微粘度.  相似文献   

3.
以环保溶剂乙酰柠檬酸三丁酯(ATBC)为稀释剂,绿色无毒的离子液体1-丁基-3-甲基咪唑六氟磷酸盐([BMIM][PF6])为添加剂,采用热致相分离(TIPS)法制备聚偏氟乙烯(PVDF)微滤膜,通过扫描电子显微镜观察不同添加剂含量PVDF膜的微观形貌;通过超滤杯对PVDF膜的纯水通量进行了测试;使用拉力计对PVDF膜的机械性能进行了表征;通过红外光谱和X-射线衍射研究了添加剂对PVDF膜晶型结构的影响。结果表明:加入1.0%[BMIM][PF6]时,PVDF的晶型变为β- 晶型。  相似文献   

4.
离子液体型表面活性剂研究   总被引:2,自引:0,他引:2  
易封萍  李积宗  陈斌 《化学学报》2008,66(2):239-244
以1-甲基咪唑为原料, 制备了6个常规离子液体: 1-正丁基-3-甲基咪唑四氟硼酸盐及六氟磷酸盐(简称[bmim][BF4]及[bmim][PF6])、1-正己基-3-甲基咪唑四氟硼酸盐及六氟磷酸盐(简称[hmim][BF4]及[hmim][PF6])、1-正十六烷基-3-甲基咪唑四氟硼酸盐及六氟磷酸盐(简称[C16mim][BF4]及[C16mim][PF6])和4个功能化离子液体: 1-(2-羟乙基)-3-甲基咪唑四氟硼酸盐及六氟磷酸盐(简称[2-hemim][BF4]及[2-hemim][PF6])、1-乙氧羰基甲基-3-甲基咪唑四氟硼酸盐及六氟磷酸盐(简称[eocmmim][BF4]及[eocmmim][PF6]). 研究了这两类离子液体的一些物理性能, 旨在挖掘离子液体在香料香精化妆品工业中的应用价值. 分别检测了它们与一般溶剂的互溶性, 并测定了它们的表面张力和发泡性能, 实验结果表明, 仅[C16mim][BF4]和[C16mim][PF6]具有发泡性能, 发泡力分别为68和120 mm.  相似文献   

5.
室温离子液体对氨基苯磺酸的萃取性能   总被引:8,自引:0,他引:8  
樊静  范云场  王键吉  崔凤灵 《化学学报》2006,64(14):1495-1499
系统研究了[C4mim][PF6], [C6mim][PF6], [C6mim][BF4]和[C8mim][BF4]室温离子液体对间氨基苯磺酸、对氨基苯磺酸稀水溶液的萃取平衡. 实验结果表明: 萃取温度和相体积比的变化对分配比影响不大; 水相pH值对萃取平衡有较大的影响, 氨基苯磺酸在离子液体/水体系中的分配比在pH=4.2时达到最大值; 水相中CaCl2或Na2SO4的存在能较大幅度地提高氨基苯磺酸的分配比; 离子液体的阴离子的性质对分配比有显著的影响, 阴离子为[BF4]的离子液体对氨基苯磺酸的萃取能力大于阴离子为[PF6]的离子液体; 咪唑环上烷基链的长度也对萃取效果有一定的影响. 在所研究的离子液体中, [C6mim][BF4]和[C8mim][BF4]对氨基苯磺酸有较好的萃取性能, 且萃取相中的氨基苯磺酸可回收利用, 离子液体也可循环使用.  相似文献   

6.
采用密度泛函理论方法比较了DBT/DBTO2和[BMIM]+[PF6]-/[BMIM]+[BF4]-的相互作用。对最稳定的[BMIM]+[PF6]-、[BMIM]+[PF6]--DBT、[BMIM]+[PF6]--DBTO2、[BMIM]+[BF4]-、[BMIM]+[BF4]--DBT、[BMIM]+[BF4]--DBTO2进行了NBO和AIM分析。结果表明,DBT和[BMIM]+[PF6]-/[BMIM]+[BF4]-中的咪唑环彼此相互平行,NBO和AIM分析表明它们之间发生了π-π相互作用。H1'和H9'形成的F…H氢键有利于π-π堆积作用的形成。DBTO2倾向于趋近C2-H2和甲基基团形成O…H相互作用;DBTO2优先吸附在[BMIM]+[PF6]-/[BMIM]+[BF4]-。在模拟油中,[BMIM]+[PF6]-和[BMIM]+[BF4]-离子液体对DBTO2的萃取能力大于DBT,其原因是可能是DBTO2具有较大的极性和O…H与F…H的氢键作用。  相似文献   

7.
研究了以1-丁基-3-甲基咪唑、四乙基铵及N-乙基吡啶为阳离子, 配以多种阴离子(H2PO4-, ClO4-, HSO4-, CH3COO-, Cl-, Br-, NO3-, SCN-, BF4-, PF6-)的离子液体对木瓜蛋白酶催化N-苯甲酰-L-精氨酸乙酯(BAEE)水解的活性及热稳定性的影响. 通过分析含离子液体体系中木瓜蛋白酶的水解活性和热力学失活参数, 发现该酶活性及稳定性与离子液体的Kosmotropicity性质无关. 因此, 离子的Hofmeister效应并不适合解释离子液体对木瓜蛋白酶催化特性的影响规律. 当以BF4-为阴离子, 改变阳离子结构时, 仅[BMIm][BF4]可提高酶活性, 其它含官能团的咪唑类离子液体则降低酶活性, 但大部分离子液体明显提高木瓜蛋白酶的热稳定性. 在所研究的离子液体中, 基于PF6-或BF4-阴离子的离子液体可提高木瓜蛋白酶的活性及其热稳定性. 在含[BMIm][PF6]介质中, 木瓜蛋白酶的水解活性最高; 在含[HOEtMIm][BF4]介质中其热稳定性最好.  相似文献   

8.
以具有支链结构的溴代仲丁烷作为烷基化试剂, 在微波辐射下采用两步法合成了1-仲丁基-3-甲基咪唑六氟磷酸盐([s-bmim][PF6])离子液体. 在配比为V(水)∶V(乙醇)∶V(甲苯)=0.16∶2.84∶7的混合溶剂体系中, 培养出晶型完整的长约11 mm的离子液体大单晶体. 通过单晶体X衍射研究了[s-bmim][PF6]的晶体结构. [s-bmim][PF6]属于三斜立方晶系, 空间群为P2(1)/m, 晶胞参数为a=0.9042(4) nm, b=0.8213(3) nm, c=0.9775(4) nm, γ=116.618°(6), Z=2, V=64.909(4) nm3, Dc=1.454 g/cm3, μ=0.265 mm-1, F(000)=292. 在[s-bmim][PF6]晶体结构中, 阴阳离子间的离子键仍然是主要的, 同时还存在氢键和阳离子-阳离子间的非键斥力作用. 研究结果表明, [s-bmim][PF6]的支化烷基结构对其晶体有效堆积、熔点、液程范围以及热分解温度等性质具有重要影响.  相似文献   

9.
田洛阳  陈亚丽  王强 《应用化学》2017,34(7):824-832
在343.15~373.15 K温度范围内,采用反气相色谱法(IGC)测试了18种有机溶剂在离子液体1-丁基-3-甲基咪唑六氟磷酸盐([BMIM]PF6)中的热力学参数。在测试温度范围内计算了有机溶剂与[BMIM]PF6之间的摩尔吸收焓、质量分数活度系数、Flory-Huggins相互作用参数、偏摩尔混合焓和无限稀释活度系数等热力学参数。结果表明,所选的有机溶剂中,正构烷烃、环己烷、四氢呋喃、乙醚和四氯化碳为[BMIM]PF6的不良溶剂。 相比之下,苯、甲苯、间二甲苯、二氯甲烷、丙酮、氯仿、乙酸乙酯、乙酸甲酯、乙醇和甲醇是[BMIM]PF6的良溶剂。  相似文献   

10.
选取具有良好生物相容性的壳聚糖(CS)包覆四氧化三铁纳米粒子(Fe3O4/CS)作为磁响应材料, 制备了磁芯负载1-丁基-3-甲基咪唑六氟磷酸盐([BMIM]PF6)凝胶微球; 对Fe3O4/CS及磁芯负载离子液体凝胶微球的组成、 结构、 微观形貌和磁性能进行了表征; 将其应用于固定化细胞技术, 在产紫青霉细胞全细胞生物催化甘草酸(GL)合成单葡萄糖醛酸基甘草次酸(GAMG)体系中, 实现了对全细胞生物催化剂和离子液体的快速回收和重复利用. 实验结果表明, 壳聚糖成功包裹Fe3O4纳米粒子; Fe3O4/CS均匀分布在凝胶微球内部, 并显示出良好的磁性能; 与凝胶微球固定化细胞催化体系相比, 磁芯负载[BMIM]PF6凝胶微球固定化细胞催化体系中GAMG的产率提高了13.8%; 重复利用实验结果表明, 磁芯负载[BMIM]PF6凝胶微球固定化产紫青霉细胞在外加磁场的作用下, 易于快速回收, 并且循环再利用9次后相对活性仍保留59.2%.  相似文献   

11.
The ZnS particles were immobilized on the surface of poly(vinylidene difluoride) (PVDF) mixing methacrylic acid (MAA)-trifluoroethyl acrylate (TFA) copolymer electrospun nanofibers. The PVDF and MAATFA copolymer nanofibers were prepared by electrospinning. Zinc ions were introduced onto the surface of nanofibers by coordinating with the carboxyls of MAA, and then sulfide ions were added to react with zinc ions to form ZnS particles under hydrothermal condition. The size and the amount of ZnS particles increased with the reaction time prolonging. The Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) results reveal that a chemical interaction exists between ZnS and fluoropolymer fibers. The degradation rate of methylene blue in ZnS-fluoropolymer nanocomposite system was considerably higher than in that of ZnS powders system under UV irradiation. There may be an adsorption-migration-photodegradation process during the degradation of methylene blue by using ZnS-fluoropolymer nanocomposites as photocatalyst. The photocatalytic activity of ZnS-fluoropolymer nanocomposites changes indistinctively after 10 times repeating tests.  相似文献   

12.
In this study, it was aimed to increase the piezoelectric and pyroelectric properties of electrospun polyvinylidene fluoride (PVDF) nanofibers simultaneously by using specific nanofillers. Graphene oxide (GO), graphene, and halloysite nanotubes with different concentrations (0, 0.05, 0.4, and 1.6% wt/wt) were combined with PVDF solution and were fabricated in the form of nanofibers through electrospinning. Pyroelectric properties of samples were measured by submerging sealed samples in hot water (360°K) and ice (270°K). The piezoelectric properties of the samples were evaluated through bending tests. The microstructural, mechanical, and thermal properties of the electrospun PVDF nanocomposite were investigated using scanning electron microscope, Instron instrument, and thermogravimetric analysis, respectively. To further support the experimental observations for generating electric voltage in the bended nanogenerator, the PVDF nanogenerator (PNG) was also modeled by a finite element analysis based on the theory of linear piezoelectricity using COMSOL Multiphysics simulation software. Experimental results showed that adding nanofillers could improve the piezoelectric and pyroelectric properties of all samples, associated with the increment of β‐phase in the nanofibers. It was concluded that adding nanofillers could increase pyroelectricity about 50% more than piezoelectricity in pristine PVDF nanofiber web. The PNG containing 1.6 wt% GO showed the highest efficiency in terms of piezoelectricity and pyroelectricity. In addition, the results showed that the ratio of piezoelectric to pyroelectric coefficients was constant (~1.5) and it was independent of the nanofiller type and content. The effect of external force and vibration frequency on the output voltage was also investigated. Increasing the compressive force and vibration frequency caused a greater output voltage. Finally, the fabricated nanogenerator was integrated on insole and elbow to investigate its energy harvesting capabilities from body movement.  相似文献   

13.
In this work,the effect of dioctadecyl dimethyl ammonium chloride(DDAC,a kind of alkyl ammonium salt) on polar β phase content and the diameter of electrospun PVDF nanofibers was investigated for the first time.Our experimental results show that the diameter of the electrospun PVDF nanofiber could be largely reduced and the content of polar β phase also become dominant immediately by just adding a little amount of DDAC.When the mass fraction of DDAC reached 4%,the content of polar β phase increased by about 39.1% compared with PVDF nanofibers without DDAC.Besides,the crystallinity of PVDF nanofibers also increased with the addition of DDAC.Based on the results,the possible mechanism of cooperative effect between electrospinning and DDAC on fiber diameter and formation of β phase in PVDF was discussed.  相似文献   

14.
陈枫  傅强 《高分子科学》2017,35(8):992-1000
In this work, the effect of dioctadecyl dimethyl ammonium chloride (DDAC, a kind of alkyl ammonium salt) on polar β phase content and the diameter of electrospun PVDF nanofibers was investigated for the first time. Our experimental results show that the diameter of the electrospun PVDF nanofiber could be largely reduced and the content of polar β phase also become dominant immediately by just adding a little amount of DDAC. When the mass fraction of DDAC reached 4%, the content of polar β phase increased by about 39.1% compared with PVDF nanofibers without DDAC. Besides, the crystallinity of PVDF nanofibers also increased with the addition of DDAC. Based on the results, the possible mechanism of cooperative effect between electrospinning and DDAC on fiber diameter and formation of β phase in PVDF was discussed.  相似文献   

15.
Polyvinylidene difluoride (PVDF) solutions containing a very low concentration of single-walled carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs) of similar surface chemistry, respectively, were electrospun, and the nanofibers formed were collected using a modified rotating disk collector. The polymorphic behavior and crystal orientation of the nanofibers were studied using wide-angle X-ray diffraction and infrared spectroscopy, while the nanotube alignment and interfacial interactions in the nanofibers were probed by transmission electron microscopy and Raman spectroscopy. It is shown that the interfacial interaction between the SWCNTs and PVDF and the extensional force experienced by the nanofibers in the electrospinning and collection processes can work synergistically to induce highly oriented beta-form crystallites extensively. In contrast, the MWCNTs could not be well aligned along the nanofiber axis, which leads to a lower degree of crystal orientation.  相似文献   

16.
Cu(OH)_2 nanowires were prepared and incorporated into poly(vinylidene fluoride)(PVDF) to fabricate Cu(OH)_2-PVDF ultrafiltration(UF) membrane via immersion precipitation phase inversion process. The effect of Cu(OH)_2 nanowires on the morphology of membranes was investigated by X-ray photoelectron spectroscopy(XPS), Fourier transform infrared(FTIR) spectroscopy, atomic force microscopy(AFM), scanning electron microscopy(SEM) and X-ray diffraction(XRD) measurements. The results showed that all the Cu(OH)_2-PVDF membranes had wider fingerlike pore structure and better hydrophilicity, smoother surface than pristine PVDF membrane due to the incorporation of Cu(OH)_2 nanowires. In addition, water flux and bovine serum albumin(BSA) rejection were also measured to investigate the filtration performance of membranes. The results indicated that all the Cu(OH)_2-PVDF membranes had high water flux, outstanding BSA rejection and excellent antifouling properties. It is worth mentioning that the optimized performance could be obtained when the Cu(OH)_2 nanowires content reached 1.2 wt%. Furthermore, the membrane with 1.2 wt% Cu(OH)_2 nanowires showed outstanding oil-water emulsion separation capability.  相似文献   

17.
Cu(OH)2 nanowires were prepared and incorporated into poly(vinylidene fluoride) (PVDF) to fabricate Cu(OH)2-PVDF ultrafiltration (UF) membrane via immersion precipitation phase inversion process.The effect of Cu(OH)2 nanowires on the morphology of membranes was investigated by X-ray photoelectron spectroscopy (XPS),Fourier transform infrared (FTIR) spectroscopy,atomic force microscopy (AFM),scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurements.The results showed that all the Cu(OH)2-PVDF membranes had wider fingerlike pore structure and better hydrophilicity,smoother surface than pristine PVDF membrane due to the incorporation of Cu(OH)2 nanowires.In addition,water flux and bovine serum albumin (BSA) rejection were also measured to investigate the filtration performance of membranes.The results indicated that all the Cu(OH)2-PVDF membranes had high water flux,outstanding BSA rejection and excellent antifouling properties.It is worth mentioning that the optimized performance could be obtained when the Cu(OH)2 nanowires content reached 1.2 wt%.Furthermore,the membrane with 1.2 wt% Cu(OH)2 nanowires showed outstanding oil-water emulsion separation capability.  相似文献   

18.
Biobased nanofibers are increasingly considered in purification technologies due to their high mechanical properties, high specific surface area, versatile surface chemistry and natural abundance. In this work, cellulose and chitin nanofibers functionalized with carboxylate entities have been prepared from pulp residue (i.e., a waste product from the pulp and paper production) and crab shells, respectively, by chemically modifying the initial raw materials with the 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) mediated oxidation reaction followed by mechanical disintegration. A thorough investigation has first been carried out in order to evaluate the copper(II) adsorption capacity of the oxidized nanofibers. UV spectrophotometry, X-ray photoelectron spectroscopy and wavelength dispersive X-rays analysis have been employed as characterization tools for this purpose. Pristine nanofibers presented a relatively low content of negative charges on their surface thus adsorbing a low amount of copper(II). The copper adsorption capacity of the nanofibers was enhanced due to the oxidation treatment since the carboxylate groups introduced on the nanofibers surface constituted negative sites for electrostatic attraction of copper ions (Cu2+). The increase in copper adsorption on the nanofibers correlated both with the pH and carboxylate content and reached maximum values of 135 and 55 mg g?1 for highly oxidized cellulose and chitin nanofibers, respectively. Furthermore, the metal ions could be easily removed from the contaminated nanofibers through a washing procedure in acidic water. Finally, the adsorption capacity of oxidized cellulose nanofibers for other metal ions, such as nickel(II), chromium(III) and zinc(II), was also demonstrated. We conclude that TEMPO oxidized biobased nanofibers from waste resources represent an inexpensive and efficient alternative to classical sorbents for heavy metal ions removal from contaminated water.  相似文献   

19.
为改善石墨烯(Gra)在聚偏氟乙烯(PVDF)中的分散性和界面性质,以甲基丙烯酸甲酯(MMA)和1-乙烯基-3-乙基咪唑溴盐(IL)为单体合成P[MMA-IL]共聚物,用于修饰石墨烯(Gra),并通过溶液共混、热压法制备PVDF/PMMA、PVDF/P[MMA-IL]、PVDF/PMMA/Gra和PVDF/P[MMA-IL]/Gra复合薄膜.采用Raman光谱、场发射扫描电子显微镜(FESEM)、傅里叶变换反射红外光谱分析仪(FTIR-ATR)、X射线衍射仪(XRD)、偏光显微镜(POM)、示差扫描量热仪(DSC)和电感电容电阻测试仪(LCR)对复合薄膜的结构形态、结晶与介电行为进行表征和分析.Raman光谱表明P[MMA-IL]与Gra之间存在强相互作用;FESEM照片显示P[MMAIL]能够促进Gra在基体中的分散;DSC、XRD和FTIR-ATR数据表明PMMA降低PVDF的结晶温度,PMMA和Gra未能诱导出?-PVDF极性晶体,而单独的P[MMA-IL]会通过咪唑阳离子-偶极子作用诱导?-PVDF晶体;通过咪唑阳离子-π强相互作用,P[MMA-IL]在模板剂Gra表面进行修饰,协同诱导作用增强.POM照片表明?-PVDF晶体在生长过程中,MMA链段会嵌入到球晶的晶片空隙中,引起结构疏松;离子-偶极子和IL成核作用导致?-PVDF晶体尺寸较小,结晶较快.介电行为研究表明PMMA及其修饰Gra降低PVDF的结晶度和链浓度,导致界面极化和取向极化较弱,介电响应较弱;而P[MMA-IL]修饰Gra诱导的?-PVDF晶体、以及IL链段在界面的离子极化使得界面极化作用增强,介电响应增强.  相似文献   

20.
A facile and low-cost superhydrophobic nanocomposite coating on paper surface was fabricated through one-step simply spraying dispersion, using hydrophobic silica nanoparticles as a filter (SiNPs) and polyvinylidene fluoride (PVDF) as a film-forming material. Hydrophobic SiNPs were fabricated via co-hydropholysis and condensation of TEOS and long-chain alkyl silane based on a simple sol-gel process, and the surface chemical structure of SiNPs was characterized by Fourier transform infrared (FTIR) spectra. The wettability and morphology of the coating surface were measured by contact angle (CA) measurement and scanning electron microscope, respectively. The influence of the mass ratio of hydrophobic SiNPs to PVDF (M(SiNPs:PVDF)) on the superhydrophobicity of paper surface was studied. The results showed that when M(SiNPs:PVDF) was 3:1, the water CA was 156.0 ± 1.0° for the nanocomposite coating with micro/nano-hierarchical structure on paper surface. Further, such superhydrophobic nanocomposite coatings on paper surface showed little adhesive property with water. In addition, the prepared superhydrophobic nanocomposite coating could be applied in other substrates, such as wood, aluminum sheet, stainless steel, polytetrafluoroethylene (PTFE), etc.  相似文献   

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