石墨烯及化学改性石墨烯的胶状悬浮物合成研究进展

详细综述了石墨烯及化学改性石墨烯(CMG)的胶状悬浮物的合成工艺进展,从氧化石墨、氧化石墨烯及石墨其他衍生物的溶解性质和合成路径等方面展开论述。石墨烯的胶状悬浮物合成工艺既提供了大批量生产石墨烯的可能性,在化学改性修饰方面也有普遍的适用性。     

石墨烯材料在重金属废水吸附净化中的应用

石墨烯材料具有较大的比表面积、良好的化学稳定性,近年来在环境污染物深度吸附处理方面的应用逐渐引起了人们的关注。本文综述了石墨烯材料在重金属离子的吸附处理方面的研究进展,包括普通石墨烯、氧化石墨烯、功能化石墨烯以及石墨烯复合物等材料;讨论了石墨烯表面功能化修饰对重金属离子吸附性能的影响;分析了各种材料的优点与缺点;提出了需进一步研究的问题,如石墨烯表面功能化修饰的结构-性能关系、石墨烯材料的循环使用以及石墨烯材料对痕量重金属离子的富集灵敏度等问题,指出合成选择性好、富集灵敏度高且可多次循环使用的石墨烯材料,在重金属废水的深度处理中将得到进一步应用。     

石墨烯在复合防腐涂层中的应用研究进展

基于石墨烯和氧化石墨烯不同的改性方法综述了石墨烯在防腐复合涂层中应用的研究进展,探讨了石墨烯防腐蚀机理,论述了石墨烯和氧化石墨稀复合防腐涂层的合成方法。其中石墨烯的改性方法有：原位改性石墨烯、电化学沉积方法和原位还原氧化石墨烯,而氧化石墨稀的改性方法包括有机改性剂改性氧化石墨烯、无机改性剂改性氧化石墨烯和微胶囊技术改性氧化石墨;并对石墨烯复合防腐涂层的发展前景进行了展望。     

氧化石墨烯剥离方法的研究进展

用石墨制备氧化石墨是大规模合成石墨烯的起点,也是实现石墨烯大量制备的有效方法之一。目前。制备氧化石墨的工艺相对成熟,而有效剥离出不同尺寸的石墨烯以满足不同的需求,还存在诸多技术难点需要突破。本文着重介绍了氧化石墨烯剥离方法的研究进展,包括热膨胀剥离、超声剥离、机械剥离、静电剥离、低温剥离等方法;最后展望了氧化石墨烯研究工作的发展前景。     

石墨烯在催化领域的应用研究进展

石墨烯的碳原子结构使其具有优异的理化特性,是近年来材料科学领域中研究的热点。石墨烯表面几乎不含有其他元素和基团,不利于进一步应用。由于氧化石墨烯、还原氧化石墨烯、元素掺杂石墨烯、功能化石墨烯、三维石墨烯等石墨烯材料表面含有丰富的基团,易于参与反应,利用这一性质制备出一系列石墨烯基复合材料,为石墨烯在催化领域中的应用提供了广阔的前景。     

改进Hummers法化学合成石墨烯及其表征

以天然鳞片石墨为原料,首先采用改进的Hummers法合成氧化石墨前驱物,再将其用硼氢化钠还原制备得到石墨烯纳米材料,采用FTIR、XRD、TEM、SEM对氧化石墨和石墨烯进行了结构与形貌分析。结果表明,制备的氧化石墨的氧化程度较高,含有大量的含氧极性基团,如羟基、羧基、醚基等;石墨烯为二维纳米薄层片状结构,边缘有皱褶起伏。     

煤基石墨烯材料制备研究进展

石墨烯材料由于其超强的力学性能,极高的电导率,超大的比表面积及良好的化学稳定性,在光、电、磁等方面的应用具有极大的潜力。煤炭资源含有大量可石墨化的芳香烃类,是制备石墨烯的天然材料。综述了采用不同技术制备氧化石墨烯、石墨烯和石墨烯量子点研究进展,总结了煤基石墨烯材料常用制备方法(化学气相沉积法和化学氧化法)的优缺点,最后对煤基石墨烯材料制备未来发展进行了展望。     

氧化石墨烯/有机高分子复合吸附材料研究进展

氧化石墨烯由于具有巨大的比表面积和丰富的含氧官能团等特性,在与有机高分子复合方面展现出巨大的应用潜力,不同材料的组合赋予了氧化石墨/有机高分子复合材料更优异的吸附性能。本文介绍了氧化石墨烯的结构和性能,综述了氧化石墨烯/有机高分子复合材料在吸附重金属离子、有机染料、放射性核素方面的研究进展,最后展望了今后的研究方向并提出了建议。     

石墨烯、氧化石墨烯改性羟基磷灰石制备及研究进展

羟基磷灰石是一种具有优秀的生物相容性以及骨传导性的材料,但因其较差的力学性能,该材料在临床上的应用受到了较大限制。石墨烯、氧化石墨烯作为新兴的材料,因为独特的层状结构而有着不错的力学性能,因此利用石墨烯、氧化石墨烯对羟基磷灰石进行改性从而提升羟基磷灰石的性能是近期研究的热点。这篇综述简要介绍了近年来关于以石墨烯及氧化石墨烯作为支撑材料对羟基磷灰石进行改性的合成方法及所得产物的性能变化,对其主要研究进展,包括制备、性能和特点进行了探究。     

石墨烯的制备与表征

采用液相氧化法制备了氧化石墨,并通过水合肼还原氧化石墨制备了石墨烯。采用傅里叶变换红外光谱(FT-IR)、拉曼光谱(RS)、X-射线衍射(XRD)、热失重法(TG)等测试方法对石墨、氧化石墨和石墨烯的结构与耐热性进行了对比分析。研究结果表明,氧化石墨被水合肼还原成石墨烯后,氧化石墨的一部分sp3杂化碳原子被还原成石墨的sp2杂化碳原子,石墨烯sp2杂化碳层平面的平均尺寸比氧化石墨大,但结晶强度和规整度比石墨有所降低。在本实验条件下,氧化石墨的还原状态结构不可能被完全恢复到原有的石墨状态,也就是说石墨烯的结构和石墨结构还是有差别的。热分析结果表明,石墨烯具有比氧化石墨更为优异的热稳定性。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.