咪唑基离子液体非共价修饰的石墨烯结构与分散性

在离子液体氯化-1-烯丙基-3-甲基咪唑（AmimCl）存在的条件下,利用水合肼对氧化石墨烯进行同步还原,制备了一种可稳定分散在N,N-二甲基甲酰胺（DMF）和乙酸丁酯等有机溶剂中的离子液体改性石墨烯（IL-G）。运用红外光谱（FTIR）、紫外-可见吸收光谱（UV-Vis）、热失重分析（TGA）、原子力显微镜（AFM）、拉曼光谱（Raman）、X射线电子衍射（XRD）和X射线光电子能谱（XPS）对制备的改性石墨烯进行结构性能测试,结果表明离子液体AmimCl与石墨烯之间存在π-π和阳离子-π的相互作用,能较好的吸附在石墨烯表面。TGA测试表明IL-G中离子液体的比例约为7.20wt%。同时,AFM结果显示改性石墨烯剥离在DMF中的平均厚度是0.962nm。由于非共价改性石墨烯可再分散于DMF和乙酸丁酯中,通过紫外可见吸收光谱测得其最大分散浓度分别是1.69mg·mL^-1和1.12mg·mL^-1。     

离子液体中氯化稀土催化ε-己内酯开环聚合

 在离子液体中进行了无水氯化稀土催化ε-己内酯(ε-CL)的开环聚合,并考察了不同氯化稀土、环氧化物、环氧化物/氯化稀土摩尔比、单体浓度、单体/氯化稀土摩尔比、反应温度和时间对聚合的影响. 结果表明,无水氯化稀土/环氧化物能有效地催化ε-己内酯在离子液体中进行开环聚合, GdCl3和ErCl3的催化活性比其他稀土氯化物高.当温度为60 ℃, 环氧丙烷/ErCl3的摩尔比为30时, ε-CL 在离子液体［bmim］BF4中聚合30 min, 单体的转化率可达到96.0%, 粘均分子量(Mv)为2.54×104. 分别采用NMR和示差扫描量热对聚合物的结构和热性能进行了表征. 结果表明, ε-CL 在离子液体中发生了酰氧键断裂,聚合的机理是配位-插入机理.     

聚季铵盐离子液体材料制备及其对蛋白质吸附性能评价

通过一步合成法制备了两种可聚合季铵盐离子液体功能单体,并通过沉淀聚合法合成了相应的聚离子液体聚合物。对产物进行了核磁共振、扫描电镜、热重分析等表征。结果表明:所制备的两种材料粒径均匀,约为600 nm的椭球形颗粒,颗粒之间有相互粘连。通过对牛血清白蛋白(BSA)、卵清蛋白(OVA)、牛血红蛋白(BHb)、溶菌酶(Lys)、胰蛋白酶(Try)5种蛋白质的吸附性能实验,考察了聚季铵盐离子液体材料对蛋白质的吸附性能。考察结果表明:两种聚离子液体材料均对蛋白质具有一定的吸附性能。其中以4-乙烯基苄氯季铵盐离子液体为功能单体制备的聚离子液体材料对胰蛋白酶的吸附性能最好,是一种具有良好应用前景的材料。     

咪唑基离子液体非共价修饰的石墨烯结构与分散性

在离子液体氯化-1-烯丙基-3-甲基咪唑(AmimCl)存在的条件下,利用水合肼对氧化石墨烯进行同步还原,制备了一种可稳定分散在N,N-二甲基甲酰胺(DMF)和乙酸丁酯等有机溶剂中的离子液体改性石墨烯(IL-G)。运用红外光谱(FTIR)、紫外-可见吸收光谱(UV-Vis)、热失重分析(TGA)、原子力显微镜(AFM)、拉曼光谱(Raman)、X射线电子衍射(XRD)和X射线光电子能谱(XPS)对制备的改性石墨烯进行结构性能测试,结果表明离子液体AmimCl与石墨烯之间存在π-π和阳离子-π的相互作用,能较好的吸附在石墨烯表面。TGA测试表明IL-G中离子液体的比例约为7.20wt%。同时,AFM结果显示改性石墨烯剥离在DMF中的平均厚度是0.962 nm。由于非共价改性石墨烯可再分散于DMF和乙酸丁酯中,通过紫外可见吸收光谱测得其最大分散浓度分别是1.69 mg·mL-1和1.12 mg·mL-1。     

单体结构对基于离子作用的自修复光固化材料性能的影响

本文研究了单体结构及其比例对基于离子作用的自修复光固化材料光聚合行为、力学性能,以及自修复性能的影响。结果表明：改变软硬单体种类及其比例不会改变自修复光固化体系的光聚合行为。增加软单体含量和降低硬单体含量,材料的拉伸应变和修复效率随之增加,断裂应力随之降低。硬单体中刚性环会增加聚合物链间的内摩擦力,使材料断裂应力增加,软单体中柔性醚链则降低链间范德华力,增强链移动性,提高材料的拉伸应变和修复效率。软单体为丙烯酸正丁酯（BA）及硬单体为丙烯酸异冰片酯（IBOA）的样品IB7-BA3展现出较好的综合性能,断裂应力为1.42 MPa,拉伸应变为295%,修复效率高于90%。     

有机-无机杂化聚离子液体材料制备及其对染料吸附性能的评价

以烯丙基三乙氧基硅烷与1-乙烯基-3-辛基咪唑溴盐离子液体为单体通过自由基聚合及溶胶-凝胶制备了有机-无机杂化聚离子液体材料。通过红外光谱和扫描电镜对所制备的杂化聚离子液体材料进行了表征,并考察了其对柠檬黄、日落黄、苋菜红以及诱惑红等常见染料的吸附性能。研究结果表明:所制备的聚离子液体材料对日落黄和诱惑红具有优异的吸附性能,其吸附容量分别为29.20和86.17 mg/g;当吸附时间为5 min时,该材料对诱惑红和日落黄的吸附分别达到平衡时吸附量的87.5%和72.8%,显示了较快的吸附速率。     

高性能丙烯酰吗啉基离子凝胶的制备及应用研究

随着柔性电子领域的发展,离子凝胶越来越受到关注。本文使用聚合物单体丙烯酰吗啉（ACMO）在离子液体1-乙基-3-甲基咪唑啉双（三氟甲基磺酰基）亚胺（EMIM TFSI）中进行一步光照聚合得到离子凝胶PAI。表征发现：PACMO与EMIM TFSI之间存在强氢键作用使离子凝胶透明度达93%,且具有良好的自修复性能。离子凝胶断裂伸长率为450%,断裂强度为1.9 MPa,对不同的基底材料都有高黏附能力。作为柔性应变传感器应用时,离子凝胶表现出高灵敏度,在长循环测试中稳定性高。不仅如此,废弃的离子凝胶还可以进行回收或重新铸型后循环使用,具有绿色无污染的特点。     

石墨烯/聚3，4-乙烯二氧噻吩复合物的电化学制备及其在超级电容器中的应用

首次提出了一种在离子液体中在石墨烯表面用恒电流法聚合3,4-乙烯二氧噻吩(EDOT)单体制备石墨烯/聚3,4-乙烯二氧噻吩(石墨烯/PEDOT)复合物的方法。用原子力显微镜、扫描电镜等技术表征证明石墨烯/PEDOT复合物是由PEDOT纳米谷粒状颗粒分散在石墨烯片表面而组成的。将该复合物用作超级电容器电极材料时,在1.0 A.g-1的充放电比电流下得到的比电容值为181 F.g-1。同时,该材料还显现出较好的充放电可逆性和稳定性。     

离子液体-脲基嘧啶酮混合型低收缩率单体的制备及应用

通过加成反应,制备了3种不同分子量的UV固化型的脲基嘧啶酮单体(UPy-PEG),同时合成了UV固化型咪唑类离子液体(IMAA),将两类单体混合,制备了3种UV固化型离子液体-脲基嘧啶酮(IMAA-UPy-PEG)混合单体。将其加入UV固化型环氧丙烯酸树脂中,体系具有较小的体积收缩率。通过核磁氢谱(~1HNMR)证实了IMAA和UPy-PEG单体的成功合成,将两者在冰浴条件下超声,可以得到均匀的混合单体IMAA-UPy-PEG。通过实时红外(RT-FTIR)证实混合单体有较高的光聚合活性。收缩率测试的结果显示混合单体添加量由10%增加到30%时,配方的最大收缩率由5.33%减小到4.81%。与商品化单体HEMA相比,体系的体积收缩率最多可下降3.6%,具有较小的收缩率。涂膜基本性能显示随着混合单体加入量的增加,涂层的硬度及光泽度略有下降,但均在可使用范围内。     

丙烯腈在1-丁基-3-甲基咪唑氯化物中的聚合及其表征

以离子液体1-丁基-3-甲基咪唑氯化物([bmim]Cl)为溶剂,研究了丙烯腈(AN)的自由基均聚和共聚反应,通过红外光谱(FT-IR)和核磁共振(NMR)分析了聚合产物的化学结构,研究了第二单体丙烯酸甲酯(MA)的含量对聚合反应速率及转化率的影响.结果表明:以离子液体为溶剂所得聚丙烯腈(PAN)的化学结构与在常规溶剂中的一致,聚合产物的组成比与投料比接近,分子量随着AN含量的增加而增大,反应转化率随着AN含量的增加先增大后减小,所得PAN的分子量分布窄(<1.7)、分子量高.差示扫描量热分析(DSC)结果表明:MA含量低于2%时有利于环化反应的控制.     

Functionalized graphene/thermoplastic polyester elastomer nanocomposites by reactive extrusion‐based masterbatch: preparation and properties reinforcement

A reactive extrusion process was developed to fabricate polymer/graphene nanocomposites with good dispersion of graphene sheets in the polymer matrix. The functionalized graphene nanosheet (f‐GNS) activated by diphenylmethane diisocyanate was incorporated in thermoplastic polyester elastomer (TPEE) by reactive extrusion process to produce the TPEE/f‐GNS masterbatch. And then, the TPEE/f‐GNS nanocomposites in different ratios were prepared by masterbatch‐based melt blending. The structure and morphology of functionalized graphene were characterized by Fourier transform infrared, X‐ray photoelectron spectroscopy, X‐ray diffraction and transmission electron microscopy (TEM). The incorporation of f‐GNS significantly improved the mechanical, thermal and crystallization properties of TPEE. With the incorporation of only 0.1 wt% f‐GNS, the tensile strength and elongation at break of nanocomposites were increased by 47.6% and 30.8%, respectively, compared with those of pristine TPEE. Moreover, the degradation temperature for 10 wt% mass loss, storage modulus at ?70°C and crystallization peak temperature (T_cp) of TPEE nanocomposites were consistently improved by 17°C, 7.5% and 36°C. The remarkable reinforcements in mechanical and thermal properties were attributed to the homogeneous dispersion and strong interfacial adhesion of f‐GNS in the TPEE matrix. The functionalization of graphene was beneficial to the improvement of mechanical properties because of the relatively well dispersion of graphene sheets in TPEE matrix, as suggested in the TEM images. This simple and effective approach consisting of chemical functionalization of graphene, reactive extrusion and masterbatch‐based melt blending process is believed to offer possibilities for broadening the graphene applications in the field of polymer processing. Copyright © 2014 John Wiley & Sons, Ltd.     

微波固相法快速制备氮掺杂石墨烯

以鳞片石墨为原料, 首先通过Hummers法制备氧化石墨, 再将洗涤至中性的氧化石墨分散液与乙二胺反应得到功能化石墨烯。干燥后的功能化石墨烯在微波辐照下能瞬间产生高热, 促使接枝的乙二胺分子分解并实现对石墨烯原位掺杂制备出氮掺杂石墨烯。利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、傅里叶变换红外光谱(FTIR)、X射线光电子能谱(XPS)、X射线衍射(XRD)、X射线能谱(EDS)对样品的形貌、结构和组成进行了表征。结果表明:该合成途径能成功实现对氧化石墨烯的还原和掺杂, 所合成的氮掺杂石墨烯呈现透明绢丝状结构。     

微波固相法快速制备氮掺杂石墨烯

以鳞片石墨为原料,首先通过Hummers法制备氧化石墨,再将洗涤至中性的氧化石墨分散液与乙二胺反应得到功能化石墨烯。干燥后的功能化石墨烯在微波辐照下能瞬间产生高热,促使接枝的乙二胺分子分解并实现对石墨烯原位掺杂制备出氮掺杂石墨烯。利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、傅里叶变换红外光谱(FTIR)、X射线光电子能谱(XPS)、X射线衍射(XRD)、X射线能谱(EDS)对样品的形貌、结构和组成进行了表征。结果表明:该合成途径能成功实现对氧化石墨烯的还原和掺杂,所合成的氮掺杂石墨烯呈现透明绢丝状结构。     

Thermoelectric properties of nanocomposite thin films prepared with poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) and graphene

Carbon nanotubes (CNTs), either single wall carbon nanotubes (SWNTs) or multiwall carbon nanotubes (MWNTs), can improve the thermoelectric properties of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT?:?PSS), but it requires addition of 30-40 wt% CNTs. We report that the figure of merit (ZT) value of PEDOT?:?PSS thin film for thermoelectric property is increased about 10 times by incorporating 2 wt% of graphene. PEDOT?:?PSS thin films containing 1, 2, 3 wt% graphene are prepared by solution spin coating method. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy analyses identified the strong π-π interactions which facilitated the dispersion between graphene and PEDOT?:?PSS. The uniformly distributed graphene increased the interfacial area by 2-10 times as compared with CNT based on the same weight. The power factor and ZT value of PEDOT?:?PSS thin film containing 2 wt% graphene was 11.09 μW mK(-2) and 2.1 × 10(-2), respectively. This enhancement arises from the facilitated carrier transfer between PEDOT?:?PSS and graphene as well as the high electron mobility of graphene (200,000 cm(2) V(-1) s(-1)). Furthermore the porous structure of the thin film decreases the thermal conductivity resulting in a high ZT value, which is higher by 20% than that for a PEDOT?:?PSS thin film containing 35 wt% SWNTs.     

Study on the preparation and mechanical properties of alumina ceramic coating reinforced by graphene and multi-walled carbon nanotube

The paper investigates preparation and mechanical performances of a composite ceramic coating reinforced by graphene and multi-walled carbon nanotube. The carbon nanotube is functionalized with the carboxyl functional group (–COOH) and un-functionalized with sodium dodecyl benzene sulfonate (SDBS). The structure of the functionalized and hybrid-functionalized carbon nanotube is identified using infrared spectroscopy (FTIR analysis). The coating is brushed on the matrix and then cures under temperature lower than 250°C. The morphological and cross section features are studied by scanning electron microscopy (SEM). The distributions of hardness and fracture toughness are determined using a microhardness tester. The adhesive strength is evaluated using a universal tensile tester. The tribological properties are detected using friction wear testing machine. The experimental results show that the structure of the composite coating is compact, and both graphene and hybridtreated carbon nanotube are well dispersed. Addition of 0.2 wt % graphene and 0.2 wt % hybrid-functionalized carbon nanotube results in a prominent increase in hardness and fracture toughness. Meanwhile, the adhesive strength between the composite coating and the metallic substrate is well improved due to the high tensile strength of both graphene and carbon nanotube. Compared with pure alumina coating, the friction coefficient as well as the wear depth and width of grinding crack of the composite coating is much lower.

     

Facile method for the preparation of water dispersible graphene using sulfonated poly(ether-ether-ketone) and its application as energy storage materials

A simple and effective method for the preparation of water dispersible graphene using sulfonated poly(ether-ether-ketone) (SPEEK) has been described. The SPEEK macromolecules are noncovalently adsorbed on the surface of graphene through π-π interactions. The SPEEK-modified graphene (SPG) forms an aqueous dispersion that is stable for more than six months. An analysis of the ultraviolet-visible spectra shows that the aqueous dispersion of SPG obeys Beer's law and the molar extinction coefficient has been found to be 149.03 mL mg(-1) cm(-1). Fourier transform infrared, Raman, and X-ray photoelectron spectroscopy analyses confirm successful reduction and surface modification of graphene. An atomic force microscopy (AFM) analysis reveals the formation of a single layer of functionalized graphene. Transmission electron microscopy results are also in good agreement with the AFM analysis and support the formation of single-layer graphene. SPG shows good electrochemical cyclic stability during cyclic voltammetry and charge/discharge process when used as a supercapacitor electrode. A specific capacitance of 476 F g(-1) at a current density of 6.6 A g(-1) is observed for SPG materials.     

Preparation and Application of Magnetically Recoverable Cationic Exchanger Support on Monodisperse Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> Nanoparticles

A magnetically recoverable cationic exchanger has been effectively prepared through immobilized chloroacetic acid (CA) onto the Fe₃O₄ nanoparticles. The magnetic nanoparticles (MNPs) were synthesized by a coprecipitation method in an aqueous system. The MNPs were modified with sodium silicate and chloroacetic acid (CA), thus endowed these nanoparticles with strong magnetism and good dispersion. The physicochemical properties of the cationic exchange materials were characterized with Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray diffraction (XRD) and thermal gravimetric analysis (TGA). The magnetic properties of the cationic exchange materials were analyzed by a vibrating sample magnetometer (VSM). The content of ions was measured by atomic absorption spectrophotometric method. The prepared cationic exchange nanoparticles display an excellent magnetic property with a saturation magnetization value of 26.58 emu/g and the prepared exchanger possess considerable thermal stability, which indicating a great potential application in heavy metal ion wastewater treatment. In this experiment, the exchange capacity of lead ion was 3.4 mmol g^–1, And the maximum lead removal rate is up to 73.85%.     

氧化石墨烯的可控还原及结构表征

采用氧化还原法, 通过控制还原时间制备了不同还原程度的石墨烯; 用红外光谱、 紫外光谱、 拉曼光谱、 X射线衍射、 热重分析、 电导率测量等多种手段系统研究了不同还原程度石墨烯的结构与性能; 采用透射电子显微镜、 扫描电子显微镜和原子力显微镜比较了氧化石墨烯和石墨烯的形貌. 结果表明, 随着还原程度的增加, 石墨烯中含氧基团减少, 紫外吸收峰逐渐红移, D带与G带的强度比增加, 热稳定性和导电性提高. 微观结构表征说明石墨烯比氧化石墨烯片的厚度增加, 褶皱增多.     

Synthesis of the polyethylene glycol solid-solid phase change materials with a functionalized graphene oxide for thermal energy storage

Polyethylene glycol (PEG) as a phase change material possesses three obstacles, such as leakage, low thermal conductivity and low thermal stability. A novel solid-solid phase change material (PCM) based on functionalized graphene oxide (GO), Polyethylene glycol (PEG) was prepared, and the three obstacles of PEG as a PCM was solved in one and the same material. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Raman and Transmission electron microscope (TEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and thermogravimetric analysis/infrared spectrometry (TG-IR) were used to study the properties of supporting material and composite PCM (CPCM). The results indicated that the PEG was grafted on the surface of the supporting material; Compared with pure PEG, the latent heat of CPCM with 9.6 wt% supporting material decreased only 5.3%, however, the thermal conductivity of CPCM increased 111% and the heat peak release rate of CPCM decreased 33.4%.     

Synthesis of adenine-modified reduced graphene oxide nanosheets

We report here a facile strategy to synthesize the nanocomposite of adenine-modified reduced graphene oxide (AMG) via reaction between adenine and GOCl which is generated from SOCl(2) reacted with graphite oxide (GO). The as-synthesized AMG was characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), UV-vis absorption spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and galvanostatic discharge analysis. The AMG owns about one adenine group per 53 carbon atoms on a graphene sheet, which improves electronic conductivity compared with reduced graphene oxide (RGO). The AMG displays enhanced supercapacitor performance compared with RGO accompanying good stability and good cycling behavior in the supercapacitor.