钼酸盐封闭后处理的热镀锌钢板硅烷膜的耐蚀性

为进一步增强硅烷膜的耐蚀性, 将硅烷化热镀锌钢板用钼酸盐溶液进行封闭后处理, 并采用扫描电子显微镜(SEM)、中性盐雾(NSS)实验、盐水全浸实验和电化学技术研究了所得复合膜层的表面形貌和耐蚀性能. 结果表明: 经钼酸盐溶液封闭处理后, 硅烷膜的孔隙被填充, 在锌层表面形成了由硅烷膜和钼酸盐转化膜构成的连续完整致密的复合膜; 复合膜的耐蚀性能明显提高, 且与钼酸盐溶液的封闭时间有关, 封闭60 s时所形成的复合膜的耐蚀性最佳. 在5%(w, 质量分数)NaCl溶液中的电化学测量结果表明: 硅烷化热镀锌钢板经钼酸盐溶液封闭处理后, 同时抑制了腐蚀过程中的阳极和阴极反应, 但主要是抑制阴极反应, 导致腐蚀电流密度明显减小, 发挥了单一硅烷膜和单一钼酸盐转化膜腐蚀防护的协同效应, 腐蚀防护效率高达99.1%; 随浸泡时间延长, 试样低频扩散阻抗先增大后减小, 表明膜层具有一定的“自愈”能力, 其耐蚀性优于常规铬酸盐钝化膜.     

丝素-氧化石墨烯-甘油复合膜的制备及性能

采用浇铸法在丝素-甘油复合膜中添加氧化石墨烯,用以改善复合膜的综合性能,通过X射线衍射(XRD)、全反射傅里叶变换红外光谱(ATR-FTIR)、力学万能试验机、场发射扫描电镜(FESEM)和溶失率测试等方法研究了氧化石墨烯对复合薄膜结构与性能的影响。结果表明:加入氧化石墨烯后,丝素的晶型由Silk I向SilkⅡ转变,拉伸强度提高了32%。氧化石墨烯在丝素的结晶过程中起到成核剂的作用;氧化石墨烯可以增加复合膜在37℃水溶液中的稳定性。     

氧化石墨烯/聚电解质层层自组装制备单价离子选择性膜

采用层层自组装法在改性聚丙烯腈(PAN)膜表面交替沉积聚乙烯亚胺(PEI)和聚丙烯酸-氧化石墨烯(PAA-GO)混合液,制得了单价离子选择性复合膜。X射线衍射(XRD)测试结果表明成功合成了氧化石墨烯(GO)并在复合膜中均匀分散。扫描电镜(SEM)观察结果证实了多层聚电解质PEI/PAA-GO成功地组装在基膜上,并用紫外-可见(UV-Vis)光谱进一步证实了组装过程的均匀性和连续性。接触角和性能测试表明加入GO后,复合膜的亲水性和单价阳离子的选择性明显增大。这种高通量、高选择性的防污复合膜在分离和水的软化方面有很好的应用前景。     

聚吡咯/聚苯胺复合型导电聚合物防腐蚀性能

采用循环伏安法,在含吡咯和苯胺的0.3 mol/L草酸水溶液中制备了聚吡咯/聚苯胺(PPy/Pani)的复合型导电聚合膜。采用红外光谱、极化曲线、自腐蚀电位-时间曲线、扫描电子显微镜和电化学阻抗谱研究了共聚膜的防腐蚀性能。结果表明,在1 mol/L H2SO4中,PPy、Pani与不锈钢基体发生氧化还原反应,促进不锈钢表面发生钝化;当苯胺与吡咯浓度比为1∶3时,制备得到的复合型导电聚合膜所保护的不锈钢自腐蚀电流最小,自腐蚀电位最高,保护时间最长。PPy、Pani及其共聚膜在3.5%NaCl溶液中电化学阻抗谱表明,所制备的PPy、Pani及其共聚物膜与不锈钢基体发生氧化还原反应,使其表面钝化;当Cl-到达不锈钢表面时,破坏钝化膜导致不锈钢腐蚀。     

不锈钢钝化膜耐蚀性与半导体特性的关联研究

通过极化曲线、交流阻抗谱和钝化膜半导体特性等电化学测量，研究了经电化学阳极氧化处理的不锈钢钝化膜在0.5 mol•L^-1 NaCl溶液中耐蚀性能与其半导体特性的关系，进一步探索电化学改性处理不锈钢钝化膜的耐蚀机理. 结果表明，不锈钢钝化膜在负于平带电位范围表现为p型半导体，在高于平带电位范围表现为n型半导体，这主要与组成钝化膜的Fe和Cr氧化物半导体性质有关. 与自然条件下形成的不锈钢钝化膜比较，发现经过电化学阳极氧化后不锈钢钝化膜具有较低的施主与受主浓度，平带电位负移，说明阴离子在钝化膜表面发生吸附. 低的施主与受主浓度及钝化膜表面负电荷的增强，可有效排斥侵蚀性Cl^－在钝化膜表面的特性吸附，有利于提高不锈钢的耐局部腐蚀性能.     

核电站结构材料的锌离子注入电化学研究

应用电化学方法研究了锌离子注入(zinc injection)技术对核电站结构材料,如304L不锈钢、316L不锈钢和600合金在高温水中形成的氧化膜的电化学性能的影响. 锌离子注入压水堆(PWR)一回路技术可有效减少材料应力腐蚀破裂(stress corrosion cracking)和职业辐照. 用动电位扫描法检测材料氧化膜的自腐蚀电位与腐蚀电流,根据Mott-Schottky曲线分析Zn离子注入对材料氧化膜半导体性质的改变. SEM和XPS观察与检测试样表面形貌及其组分. 在Zn离子参与的金属氧化膜生成过程中,可生成Zn-Ni-Cr-Fe 氧化物,从而提高了材料的抗腐蚀能力及改变氧化膜的半导体性质.     

石墨烯分散液及其组装膜的性能

通过对比表面活性剂十二烷基硫酸钠(SDS)和聚乙烯醇(PVA)对石墨烯的分散能力,发现SDS可有效避免石墨烯片层之间的团聚,使得石墨烯在水溶液中分散得更加均匀.将浓度分别为0.39和0.30 mg/m L的石墨烯(G)和石墨烯片(GF)的SDS分散液旋涂在ITO电极表面制备出G膜和GF膜.透射电子显微镜和原子力显微镜观测结果表明,两类石墨烯膜均呈现出纱状透明的片状结构,同时具有石墨烯特有的褶皱.在石墨烯膜上继续进行钌配合物分子膜的自组装实验,得到G/Ru复合膜和GF/Ru复合膜.采用循环伏安法及紫外-可见吸收光谱法对石墨烯复合膜进行光电化学分析,结果表明石墨烯膜与钌配合物分子膜的复合可有效加强薄膜对太阳光的吸收.     

羧基功能化石墨烯及其壳聚糖复合膜的制备与性能

采用Hummers法制备氧化石墨,化学分散法制备羧基功能化石墨烯。采用FT-IR、XRD对产物进行表征;用静电自组装法将其与壳聚糖（CS）复合制备复合膜,对复合膜的荧光性能及其修饰玻碳电极对葡萄糖的电催化氧化还原性能进行了研究。结果表明：制备的功能化石墨烯含有羧基;壳聚糖-石墨烯复合膜具有光致发光性能;复合膜修饰玻碳电...     

抗菌处理含铜铁素体不锈钢的耐微生物腐蚀性能

采用电化学测试技术及微生物学方法, 研究了抗菌处理含铜铁素体不锈钢在含有培养基的异养菌溶液中的耐蚀性能. 结果表明, 不锈钢的腐蚀电位随异养菌的新陈代谢呈现规律性变化, 抗菌处理使不锈钢在菌液中钝化膜的稳定性得到改善, 点蚀敏感性降低; 抗菌不锈钢表面弥散分布的ε-Cu析出相的杀菌作用, 降低了异养菌的活性, 减缓了异养菌对抗菌不锈钢的腐蚀, 提高了抗菌不锈钢耐微生物腐蚀性能.     

氧化石墨烯/聚合物复合质子交换膜研究进展

氧化石墨烯/聚合物复合质子交换膜(GO/Polymer blend PEM)是一种新型的质子交换膜,广泛应用于直接甲醇燃料电池(DMFC)中,已成为质子交换膜研究的热点之一。氧化石墨烯/聚合物复合质子交换膜具有较高的传导质子率、力学性能、阻醇性能和电池性能。本文综述了氧化石墨烯(GO)处理方法、氧化石墨烯/聚合物复合质子交换膜制备方法,氧化石墨烯/聚合物复合质子交换膜的质子传导、阻醇、离子交换容量和电池的性能,氧化石墨烯/聚合物复合质子交换膜质子传递机理及阻醇机理。     

Chitin/graphene oxide composite films with enhanced mechanical properties prepared in NaOH/urea aqueous solution

Chitin/graphene oxide (GO) composite films with excellent mechanical properties were prepared in NaOH/urea solution using a freezing/thawing method. The structure, thermal stability and mechanical properties of the composite films were investigated. Use of an atomic force microscope and transmission electron microscopy indicated that GO was successfully exfoliated to a single layer by ultrasonication. The results revealed that GO nanosheets were homogeneously dispersed and embedded in the chitin matrix. Due to the strong interactions between GO and the chitin matrix, the tensile strength and elongation at break of the composite film possessing 1.64 wt% GO were significantly improved by 98.7 and 114.5 %, respectively, compared with pure chitin film.     

Preparation of porous polyimide/in‐situ reduced graphene oxide composite films for electromagnetic interference shielding

Herein we report an easy and efficient approach to prepare lightweight porous polyimide (PI)/reduced graphene oxide (RGO) composite films. First, porous poly (amic acid) (PAA)/graphene oxide (GO) composite films were prepared via non‐solvent induced phase separation (NIPS) process. Afterwards PAA was converted into PI through thermal imidization and simultaneously GO dispersed in PAA matrix was in situ thermally reduced to RGO. The GO undergoing the same thermal treatment process as thermal imidization was characterized with thermogravimetric analysis, Raman spectra, X‐ray photoelectron spectroscopy and X‐ray diffraction to demonstrate that GO was in situ reduced during thermal imidization process. The resultant porous PI/RGO composite film (500‐µm thickness), which was prepared from pristine PAA/GO composite with 8 wt% GO, exhibited effective electrical conductivity of 0.015 S m^?1 and excellent specific shielding efficiency value of 693 dB cm² g^?1. In addition, the thermal stability of the porous PI/RGO composite films was also dramatically enhanced. Compared with that of porous PI film, the 5% weight loss temperature of the composite film mentioned above was improved from 525°C to 538°C. Moreover, tensile test showed that the composite film mentioned above possessed a tensile strength of 6.97 MPa and Young's modulus of 545 MPa, respectively. Copyright © 2016 John Wiley & Sons, Ltd.     

Nanocrystalline cellulose acetate (NCCA)/graphene oxide (GO) nanocomposites with enhanced mechanical properties and barrier against water vapor

Highly flexible nanocomposite films of nanocrystalline cellulose acetate (NCCA) and graphene oxide (GO) were synthesized by combining NCCA and GO sheets in a well-controlled manner. By adjusting the GO content, various NCCA/GO nanocomposites with 0.3–1 wt% GO were obtained. Films of these nanocomposites were prepared using the solvent casting method. Microscopic and X-ray diffraction (XRD) measurements demonstrated that the GO nanosheets were uniformly dispersed in the NCCA matrix. Mechanical properties of the composite films were also studied. The best GO composition of the samples tested was 0.8 wt%, giving tensile strength of 157.49 MPa, which represents a 61.92 % enhancement compared with NCCA. On the other hand, the composite films showed improved barrier properties against water vapor. This simple process for preparation of NCCA/GO films is attractive for potential development of high-performance films for electrical and electrochemical applications.     

LDPE/EVA/graphene nanocomposites with enhanced mechanical and gas permeability properties

In the present work, graphene oxide (GO) and reduced graphene oxide (RGO) were incorporated at low‐density polyethylene (LDPE)/ethylene vinyl acetate (EVA) copolymer blend using solution casting method. Monolayer GO with 1‐nm thickness and good transparency was synthesized using the well‐known Hummers's method. Fourier transform infrared and X‐ray photoelectron spectroscopy data exhibited efficient reduction of GO with almost high C/O ratio of RGO. Scanning electron microscopy showed the well distribution of GO and RGO within LDPE/EVA polymer matrix. The integrating effects of GO and RGO on mechanical and gas permeability of prepared films were examined. Young's modulus of nanocomposites are improved 65% and 92% by adding 7 wt% of GO and RGO, respectively. The tensile measurements showed that maximum tensile strength emerged in 3 wt% of loading for RGO and 5 wt% for GO. The measured oxygen and carbon dioxide permeability represented noticeably the attenuation of gas permeability in composite films compared with pristine LDPE/EVA blend. Copyright © 2015 John Wiley & Sons, Ltd.     

A new solid-phase nanoparticle FRET assays based on GO/CS/ZnS nanocomposite film and developed in sensing for bromonium ion

Composite thin films consisting of nano-sized ZnS particles dispersed in chitosan/GO films have been prepared by in-situ method. The films obtained were characterized by FTIR and UV–Vis spectroscopy. The ZnS nanoparticles with 90 nm in diameter were dispersed uniformly in the film matrix. Optical absorption peak due to the size of ZnS particles was observed around 350 nm. The fluorescence emission at 430 nm of the GO/CS/ZnS nanocomposite films is very sensitive to the presence of bromonium ion from aqueous solutions. New solid-phase nanoparticles FRET assays are firstly immobilized on the substrate and then interacted with functionalized acceptor molecules in the solution to trigger the FRET effect to detect Br^–.     

金属表面硅烷试剂防腐涂层性能测试

硅烷试剂(SilaneAgent,SA)直接用作金属表面预处理时,可与金属表面的氧化层形成化学键合而改变金属表面的性质,特别对提高难上漆的金属表面的附着力具有令人瞩目的效果;因其具有无污染、处理件耐蚀性好、与涂层结合牢固等特点,目前正成为硅烷试剂应用的新兴领域[1～3].通过有效的测试手段对体系进行监测和判断是开发利用该技术的前提,有关这方面报道极少,本文在工艺技术研究的基础上提出和建立了相应的分析测试方法.SA和SA(CR);乙醇(工业级95%);醋酸(CR):36%使用液;其它试剂均为CR级;防锈水(亚硝酸盐型)和防锈水(过氧化氢型)按工业常…     

Approach to excellent superhydrophobicity and corrosion resistance of carbon-based films by graphene and cobalt synergism

A new series of carbon-based films doped with graphene oxide and cobalt (G-Co/a-C:H films) were successfully prepared on Si substrate via one-step electrochemical deposition of methanol as the carbon source and graphene oxide/cobalt as the dopant. G-Co/a-C:H films were fabricated at various graphene oxide concentration for comparative experiments. It can be found that the graphene oxide and cobalt were well embedded in amorphous carbon matrix to form superhydrophobic G-Co/a-C:H film at the doping GO concentration of 0.007 mg/mL, which was confirmed by transmission electron microscopy (TEM). It was noted that the superhydrophobicity of the resulting surface derives from its rough surface with hierarchical micro-nanostructures and the presence of the low-surface-energy GO components on it. The hierarchical micro-nanostructures are attributed to the corporate joint of GO and cobalt to form the multilevel nanoscale composite interface. Specially, the as-fabricated superhydrophobic G-Co/a-C:H film could exhibit excellent self-cleaning ability and corrosion resistance, revealed by the self-cleaning and corrosion tests.     

可见光高催化活性GO/Ag3PO4/Ni复合薄膜的制备和性能

以磷酸铵和氧化石墨烯悬浊液的混合液为电解液,采用电化学共沉积法制备了Ag3PO4基GO/Ag3PO4/Ni复合薄膜。运用扫描电子显微镜(SEM)、能量色散谱(EDS)、X射线衍射(XRD)、拉曼光谱(Raman)和紫外可见漫反射光谱(UV-Vis DRS)等对其形貌、物相和光谱特性进行分析。最佳工艺制备的GO/Ag3PO4/Ni复合薄膜呈现出GO包覆在直径为100 nm左右的Ag3PO4纳米球外的表面形貌。GO片与Ag3PO4纳米球之间存在强电荷相互作用。与单独的Ag3PO4纳米球相比,GO片的附着导致带隙缩小,可见光区的吸收率增强。可见光下考察了复合薄膜降解罗丹明B的光催化活性和稳定性,并利用荧光光谱和捕获剂法对薄膜的光催化机理进行了探索。结果表明,GO片的加入不仅显著提高了Ag3PO4的光催化活性,而且提高了Ag3PO4的结构稳定性。光催化降解罗丹明B 60 min时,GO/Ag3PO4/Ni复合薄膜的降解率是Ag3PO4/Ni薄膜的1.32倍。在保持薄膜光催化活性基本不变的前提下可循环使用7次。GO优异的电荷传导性能,以及Ag3PO4纳米球与GO片之间的正协同效应是提高复合薄膜光催化性能的主要原因。     

氧化石墨烯在氧化锌衬底上的电化学还原及其光电性能

采用阳极电泳法,在氧化锌(ZnO)衬底上沉积氧化石墨烯(GO)以形成GO-ZnO双层复合膜;采用阴极恒电位法,对复合膜上的GO进行还原。对不同还原时间的GO,通过X射线光电子能谱(XPS),傅里叶变换红外(FTIR)光谱,场发射扫描电子显微镜(FESEM)等手段对其结构变化进行表征,采用紫外-可见(UV-Vis)分光光度法和电化学测试手段对其能级演变进行考察,并对两者的对应关系进行了讨论。研究发现,当GO膜达到最大还原态后,随还原时间增加还会出现进一步的结构转变,并最终碎裂生成边缘羧基增多的小尺寸GO。GO能隙均减小至可见光范围,其能级位置及半导体极性也产生了不同的改变。由对复合膜的光电化学测试可见,除1800 s GO能级不再与ZnO匹配外,60 s到600 s GO-ZnO复合膜均可作为阳极光电极进行太阳光电转换。对光电性能差异的讨论则可得,GO膜碎裂造成叠层形貌向无序形貌的转变有利于光电转换性能的提升。