氧化石墨插层纳米复合材料的制备研究进展

氧化石墨（GO）插层纳米复合材料是一种新型的纳米复合材料。介绍了氧化石墨的结构、制备方法和性质；重点论述了聚合物/氧化石墨插层纳米复合材料和无机物/氧化石墨插层纳米复合材料的制备研究进展，介绍了半导体氧化物/氧化石墨插层纳米复合材料。     

一步法制备聚苯乙烯/MoS2插层复合材料及结构与氧化行为研究

用阴离子聚合法原住一步合成了PS／MoS2插层复合材料，通过XRD、FT-IR及SEM对复合材料的结构进行了表征，结果表明，MoS2经聚苯乙烯插层后，层间距扩大了0．672nm，形成的是插层型复合材料。通过XPS对一步法和两步法(剥层重堆法)制备的插层复合材料的氧化行为进行了研究，结果表明，一步法和两步法合成的PS／MoS2插层复合材料的氧化行为不同，前者主要是MoS2中的Mo^4 氧化为Mo^6 ，后者主要是MoS2中的S^2-氧化为S^6 。     

聚丙烯酰胺/氧化石墨纳米复合材料的研究

氧化石墨具有良好的层状结构，其层间具有丰富的官能团，能与有机聚合物形成插层纳米复合材料进而改善材料的性能．采用层离吸收-原位聚合法制备了聚丙烯酰胺／氧化石墨纳米复合材料，并采用XRD、HREM及DSC等对其结构和性能进行了表征。结果表明，聚丙烯酰胺与氧化石墨两者之间存在着较强的相互作用，材料的玻璃化转变温度得到提高，层离吸收-原位聚合法是获得聚丙烯酰胺／氧化石墨层纳米复合材料的有效途径，聚丙烯酰胺在氧化石墨中存在着多种排列方式，不同层间距(1．6nm和2．8nm)的聚丙烯酰胺／氧化石墨纳米复合结构同时存在。     

部分氧化法制备插层石墨/Mn_3O_4复合材料及其电化学性能研究

用浓硫酸、浓硝酸对石墨进行氧化处理,在水浴条件下再将其与高锰酸钾反应,制得插层石墨/四氧化三锰(Mn_3O_4)复合电极材料。并对材料的形貌、结构和电化学进行表征和分析。研究结果表明,水浴回流制备的插层石墨/Mn_3O_4复合材料,具有类石墨结构,呈针状,比表面积大,具有优异超级电容性能。恒流充放电表明,插层石墨/Mn_3O_4复合材料比/Mn_3O_4具有较大的电流放电能力,在1.0A/g电流密度下,插层石墨/Mn_3O_4复合材料比电容为242F/g,Mn_3O_4比电容为112F/g,插层石墨/Mn_3O_4复合材料的比电容比Mn_3O_4高116%。在电流密度0.1A/g时,插层石墨/Mn_3O_4复合材料的比电容为328F/g。     

WO3·0.33H2O及其与石墨插层复合材料的光催化性能研究

制备了WO3·0.33H2O及其插层石墨的复合材料(GIW),对材料进行了相应的表征,并比较了WO3·0.33H2O和石墨插层复合材料的光催化性能,发现WO3·0.33H2O石墨插层复合材料在紫外光下具有较之WO3·0.33H2O更优越的光催化性能.通过XRD、XPS、FT-IR、HRTEM等测试手段,分析了WO3·0.33H2O和GIW的晶相、微观结构,结果表明插层材料保持了WO3·0.33H2O的晶相,且WO3·0.33H2O被层状石墨包覆,有利于电子的转移;伏安循环法测试材料的氧化还原电位表明插层材料具有更负的导带位置.     

加压密闭氧化石墨烯/水性聚氨酯纳米复合材料的制备及阻燃性能

采用改进的Hummers法对可膨胀石墨进行加压密闭氧化处理制备了氧化石墨烯(GO),并利用X射线衍射分析、紫外可见吸收光谱和透射电镜对其进行了表征。利用原位乳化法制备了氧化石墨烯/水性聚氨酯(GO/WPU)纳米复合材料。研究了GO含量对GO/WPU纳米复合材料的稳定性、形态、热降解性能和阻燃性能的影响。Zeta电位和扫描电镜的研究表明,GO在GO/WPU纳米复合材料中具有良好的稳定性和分散性。热失重分析结果表明,和纯WPU相比,GO/WPU纳米复合材料的热稳定性略有降低,但800℃时含量2%GO的纳米复合体系的残炭量从0.99%增大到2.90%。锥形量热仪分析结果表明,随着GO在GO/WPU纳米复合材料中的含量增大,材料的阻燃抑烟性能逐渐增强。当GO的含量为2%时,和纯WPU相比,GO/WPU纳米复合材料的峰值热释放速率、总释放热、总烟释放以及烟因子分别降低了34%,19%,27%和43%。     

添加剂对聚吡咯/氧化石墨纳米复合材料结构和性能的影响

采用单体原位聚合法制备了三种聚吡咯/氧化石墨纳米复合材料。通过XRD、FT-IR和TEM对产物进行结构表征,探讨了未加添加剂及分别以N aOH和十二烷基苯磺酸钠为添加剂制得的聚吡咯/氧化石墨纳米复合材料的结构与性能的差别。结果表明,未加添加剂和以N aOH为添加剂时产物为非晶态的剥离型聚吡咯/氧化石墨纳米复合材料;而以十二烷基苯磺酸钠为添加剂时可得到具有层状有序结构的插层型聚吡咯/氧化石墨纳米复合材料。插层型聚吡咯/氧化石墨纳米复合材料的导电和电化学性能优于剥离型聚吡咯/氧化石墨纳米复合材料,它们的提高归因于聚吡咯分子链共轭程度的增加。     

功能化氧化石墨烯/聚氨酯-环氧树脂复合材料的制备及其性能

利用氧化石墨烯(GO)表面的羟基分别与硅烷偶联剂KH550、KH560反应,制备功能化氧化石墨烯(KH550-GO、KH560-GO),分析了GO功能化前后的微观结构变化;通过溶液插层法将GO加入到聚氨酯-环氧树脂(PU-EP)基体树脂中制备GO/PU-EP复合材料,并对其拉伸性能及热性能进行测试。研究结果表明,KH550、KH560成功对GO进行了功能化,并且与PU-EP复合材料相比,GO/PU-EP复合材料的拉伸性能和热性能均有明显的提高。其中,KH550-GO的加入对基体树脂力学性能和热性能的改善尤为明显。添加0.1wt%的KH550-GO,基体树脂拉伸强度和拉伸模量分别提高了39.0%和94.4%,同时初始热分解温度提高了12℃。     

石墨烯/环氧树脂复合材料的介电性能研究

通过Staudenmaier法制备了完全氧化的氧化石墨(GO),并通过高温热膨胀制备了单层石墨烯(graphene)。用FT-IR和TG对GO的氧化程度、含氧官能团进行了表征,用SEM和TEM对天然石墨(NG)、GO和graphene的微观结构进行了分析。利用超声共混法制备了graphene/环氧树脂介电纳米复合材料,介电性能的测试表明,graphene的加入使环氧树脂介电常数大幅提高,当graphene添加量为0.25%(质量分数)时,材料介电常数达到25,是纯环氧树脂的4倍,介电损耗0.11。这为石墨烯在介电储能方面的应用和低成本介电复合材料的制备提供了新思路。     

新型抗凝血纳米复合材料的制备及其性能研究

利用溶液插层法合成了新型的硅橡胶/氧化石墨-十六烷基三甲基溴化铵-肝素抗凝血纳米复合材料.通过FT-IR、XRD、SEM和机械性能测试了解改性氧化石墨微观纳米结构对材料宏观性能的影响;溶血试验和血小板粘附试验测定表明硅橡胶/改性氧化石墨抗凝血纳米复合材料的血液相容性得到极大的改善;这种新型的、兼具优良血液相容性和良好力学性能的复合材料可望在生物医学工程方面得到应用.     

Morphology, mechanical and thermal properties of graphene-reinforced poly(butylene succinate) nanocomposites

Graphene nanosheets (GNSs) reinforced poly(butylene succinate) (PBS) nanocomposites are facilely obtained by a solution-based processing method. Graphene nanosheets, which are derived from chemically reduced graphite oxide (GO), are characterized by AFM, TEM, XRD and Raman spectra. The state of dispersion of the GNSs in the PBS matrix is examined by SEM observations that reveals homogeneous distribution of GNSs in PBS matrix. A 21% increase in tensile strength and a 24% improvement of storage modulus are achieved by addition of 2.0 wt% of GNS. The electrical conductivity and thermal stability of the graphene-based nanocomposite are also improved. DSC measurement indicates that the presence of graphene sheets does not have a remarkable impact on the crystallinity of the nanocomposites. Therefore, the high performances of the nanocomposites are mainly attributed to the uniform dispersion of GNSs in the polymer matrix and strong interfacial interactions between both components.     

Micro-structure of graphite-intercalated tin oxide and its influence on SnO2-based gas sensors

A nano-scaled graphite oxide (GO) was prepared with a micro-layer structure for intercalation. Graphite-intercalated SnO₂ was obtained at temperatures lower than 100vH. The morphology, microstructure, crystalline phases and thermal property of this intercalative composite were studied by atomic force microscopy (AFM), field-emission scanning electron microscopy (FE-SEM), X-ray diffractometry (XRD) and differential scanning calorimetrythermogravimetry (DSC-TG) doped with a proper amount of graphite-intercalated composites (GITs), GIT-SnO2 composite was obtained after heat treatment. This combined gas sensor reveals low resistance and high sensitivity to butane between 200vH and 300vH.     

Nanocomposite nanofibers of poly(d, l-lactic-co-glycolic acid) and graphene oxide nanosheets

Significant improvements in the thermomechanical and surface chemical properties of nanocomposite nanofibers of poly(d, l-lactic-co-glycolic acid) (PLGA) were achieved by adding 2-dimensional nanoscale fillers of graphene oxide (GO) nanosheets to PLGA nanofibers. The significant enhancement of storage and loss moduli of the PLGA/GO (2 wt.%.) nanocomposite nanofibers were presumably caused by enhanced chemical bonding between the oxygenated functional groups of the highly dispersible GO nanosheets and the hydroxyl groups of the polymer chains in the PLGA matrix, resulting in strong interfacial interactions between the nanofiller and polymer matrix. Enhanced hydrophilicity of nanocomposite nanofibers caused by embedded GO nanosheets also allowed for good biocompatibility of neuronal cells, resulting in enhanced cell proliferation and viability. Our findings indicate that nanocomposite biopolymer nanofibers embedded with GO nanosheets are attractive candidates for use in biomedical applications such as scaffolds.     

Influence of Surface-functionalized Graphene Oxide on the Cell Morphology of Poly(methyl methacrylate) Composite

The surface chemistry of filler is closely related to the structure and morphology of nanocomposite foams.Changing the property of filler is widely used to control the cell structures and functionalize the composite foams.Surface-functionalized graphene oxide(GO-ODA) was prepared by grafting octadecylamine(ODA) on the surface of graphene oxide(GO) to make the filler disperse better in the nanocomposites and have a strong interfacial interaction with polymer matrix.Poly(methyl methacrylate)(PMMA)/GO-ODA nanocomposite foams were obtained by solution blending and foamed using supercritical carbon dioxide(scCO_2).Compared to neat PMMA and PMMA/GO samples,the PMMA/GO-ODA nanocomposite foams showed improved cell structures with smaller size,higher cell density and more homogeneous distribution,which should be attributed to the heterogeneous nucleation caused by well-dispersed GO-ODA nanosheets.This work not only improved the compatibility and interfacial interaction of GO with polymer matrix but also indicated that the modified GO sheets can act as ideal filler to control the cell density,size and size distribution efficiently.     

One step synthesis of β-FeOOH nanowire bundles/graphene oxide nanocomposites

A nanocomposite of graphene oxide (GO) and β-ferric oxyhydroxide (β-FeOOH) nanowire bundles is synthesized by in situ hydrolysis of the precursor ferric chloride and GO nanosheets. Characterization by X-ray diffraction, transmission electron microscopy, and thermogravimetric analysis established the composite structure of the synthesized sample. The results revealed that the surface of GO nanosheets was uniformly assembled by numerous nanowire bundles with diameters in the range of 30–50 nm and lengths of 100–150 nm. Furthermore, β-FeOOH/GO nanocomposites showed a very high adsorption capacity of Congo red and thus these nanocomposites can be used as good adsorbents and can be used for the removal of organic dye from the waste water system.     

Electrical and electrochemical properties of poly(2,5-dimercapto-1,3,4-thiadiazole)-polyaniline adduct intercalated graphite oxide composites

Poly(2,5-dimercapto-1,3,4-thiadiazole-polyaniline) adduct (PDMcT-PANI) was synthesized by chemical oxidative polymerization. It indicates that electrons are transferred between the PANI and the PDMcT to form the electron donor-acceptor adduct. PDMcT-PANI intercalated graphite oxide composites (PDMcT-PANI/GO) were synthesized by delamination/reassembling method. The hydrogen bond is formed between the –NH and –SH groups of PDMcT-PANI and the carboxyl groups at the edges of the GO, which is confirmed by FTIR. XRD and TEM results show that the PDMcT-PANI/GO composites still maintain good lamellar structure after intercalation, and the interlayer spacing (I_c values) of the GO is enlarged with the addition of the PDMcT-PANI. PDMcT-PANI/GO composites provide better thermal stability compared with pristine GO and PDMcT-PANI. In addition, the intercalation of PDMcT-PANI also improves the electrical conductivity and electrochemical properties of the composites.     

In situ thermal preparation of polyimide nanocomposite films containing functionalized graphene sheets

Graphene oxides (GO) were exfoliated in N,N-dimethylformamide by simple sonication treatment of the as-prepared high quality graphite oxides. By high-speed mixing of the pristine poly(amic acid) (PAA) solution with graphene oxide suspension, PAA solutions containing uniformly dispersed GO can be obtained. Polyimide (PI) nanocomposite films with different loadings of functionalized graphene sheets (FGS) can be prepared by in situ partial reduction and imidization of the as-prepared GO/PAA composites. Transmission electron microscopy observations showed that the FGS were well exfoliated and uniformly dispersed in the PI matrix. It is interesting to find that the FGS were highly aligned along the surface direction for the nanocomposite film with 2 wt % FGS. Tensile tests indicated that the mechanical properties of polyimide were significantly enhanced by the incorporation of FGS, due to the fine dispersion of high specific surface area of functionalized graphene nanosheets and the good adhesion and interlocking between the FGS and the matrix.     

In situ thermal reduction of graphene oxide for high electrical conductivity and low percolation threshold in polyamide 6 nanocomposites

Electrically conductive and thermally stable polyamide 6 (PA 6) nanocomposites were prepared through one-step in situ polymerization of ε-caprolactam monomer in the presence of electrically insulating and thermally unstable graphene oxide (GO) nanosheets. These nanocomposites show a low percolation threshold of ∼0.41 vol.% and high electrical conductivity of ∼0.028 S/m with only ∼1.64 vol.% of GO. Thermogravimetric analysis and X-ray photoelectron spectroscopy results of GO before and after thermal treatment at the polymerization temperature indicate that GO was reduced in situ during the polymerization process. X-ray diffraction patterns and scanning electron microscopy observation confirm the exfoliation of the reduced graphene oxide (RGO) in the PA 6 matrix. The low percolation threshold and high electrical conductivity are attributed to the large aspect ratio, high specific surface area and uniform dispersion of the RGO nanosheets in the matrix. In addition, although GO has a poor thermal stability, its PA 6 nanocomposite is thermally stable with a satisfactory thermal stability similar to those of neat PA 6 and PA 6/graphene nanocomposite. Such a one-step in situ polymerization and thermal reduction method shows significant potential for the mass production of electrically conductive polymer/RGO nanocomposites.     

g-C3N4/MoS2纳米片/氧化石墨烯三元复合催化剂的制备及可见光催化性能

采用球磨法制备 g-C₃N₄/MoS₂纳米片/氧化石墨烯(GO)三元复合催化剂。运用X 射线衍射(XRD)、透射电子显微镜(TEM)、紫外-可见吸收光谱(UV-Vis)和光致激发光谱(PL)等分析手段, 对催化剂的结构、形貌和光学性能进行表征。结果表明: MoS₂纳米片和g-C₃N₄形成异质结结构, 均匀地分散在氧化石墨烯的表面上。以罗丹明B(RhB)为模拟污染物, 研究三元复合催化剂在可见光照射下的光催化特性。结果显示: 三元复合催化剂在120 min内对RhB的降解率达到96%, 其降解动力学常数分别是g-C₃N₄、g-C₃N₄/ MoS₂、g-C₃N₄/GO复合催化剂的3、2.1和2.8倍。根据实验结果及能带结构提出了三元复合催化剂可能的光催化机理。