The use of fillers in fiber-reinforced epoxy matrix composites to enhance the wear performance of the composite is a widely employed method nowadays. In this study, the effect of incorporating ...graphite filler into a glass fiber-reinforced composite structure on the tribological properties of the composite was investigated. Composite materials produced using the hand lay-up method with three different levels of graphite filler were compared to unfilled composites in terms of wear behavior under different loads (7 N, 10 N, 15 N) and sliding distances (200 m, 400 m). The influence of load, filler content, and sliding distance on the friction coefficient and wear rate was discussed. When the results are examined, the significant effects of graphite filler on wear volume and friction coefficient are clearly observed. In the composite containing 12% graphite, the wear volume has decreased by almost 96%; this ratio has been around 93% for the composite with 4% graphite filler. As the reinforcement of graphite and force increase, the friction coefficient decreases, whereas with the increase in sliding distance, the friction coefficient declines. Microstructural analysis revealed that the filled composites exhibited less abrasion compared to the unfilled composites, and the surface porosity and craters were shallower.
Graphene Oxide Dimiev, Ayrat M; Eigler, Siegfied
2016, 2016-09-27
eBook
Due to its unique properties, graphene oxide has become one of the most studied materials of the last decade and a great variety of applications have been reported in areas such as sensors, catalysis ...and biomedical applications. This comprehensive volume systematically describes the fundamental aspects and applications of graphene oxide. The book is designed as an introduction to the topic, so each chapter begins with a discussion on fundamental concepts, then proceeds to review and summarize recent advances in the field. Divided into two parts, the first part covers fundamental aspects of graphene oxide and includes chapters on formation and chemical structure, characterization methods, reduction methods, rheology and optical properties of graphene oxide solutions. Part Two covers numerous graphene oxide applications including field effect transistors, transparent conductive films, sensors, energy harvesting and storage, membranes, composite materials, catalysis and biomedical applications. In each case the differences and advantages of graphene oxide over its non-oxidised counterpart are discussed. The book concludes with a chapter on the challenges of industrial-scale graphene oxide production.Graphene Oxide: Fundamentals and Applications is a valuable reference for academic researchers, and industry scientists interested in graphene oxide, graphene and other carbon materials.
Providing fundamental knowledge necessary to understand graphene's atomic structure, band-structure, unique properties and an overview of groundbreaking current and emergent applications, this new ...handbook is essential reading for materials scientists, chemists and physicists. Since the 2010 physics Nobel Prize awarded to Geim and Novosolev for their groundbreaking work isolating graphene from bulk graphite, there has been a huge surge in interest in the area. This has led to a large number of news books on graphene. However, for such a vast inflow of new entrants, the current literature is surprisingly slight, focusing exclusively on current research or books on previous "hot topic" allotropes of carbon. This book covers fundamental groundwork of the structure, property, characterization methods and applications of graphene, along with providing the necessary knowledge of graphene's atomic structure, how it relates to its band-structure and how this in turn leads to the amazing properties of graphene. And so it provides new graduate students and post-docs with a resource that equips them with the knowledge to undertake their research.
Discusses graphene's fundamental structure and properties, acting as a time-saving handbook for validated researchDemonstrates 100+ high-quality graphical representations, providing the reader with clear images to convey complex situationsReviews characterization techniques relevant to grapheme, equipping the reader with experimental knowledge relevant for practical use rather than just theoretical understanding
All set to become the standard reference on the topic, this book covers the most important procedures for chemical functionalization, making it an indispensable resource for all chemists, physicists, ...materials scientists and engineers entering or already working in the field. Expert authors share their knowledge on a wide range of different functional groups, including organic functional groups, hydrogen, halogen, nanoparticles and polymers.
•This is the first experimental about the fire reaction behaviour by testing bulk-PCM.•Paraffin RT-21 and fatty acid mixtures fire reaction in bulk-form were evaluated.•Fire retardancy was enhanced ...by the addition of hydromagnesite and Mg(OH)2.•Fatty acids enthalpy decreased by the addition of flame retardants.•For paraffin, melting enthalpy did not decrease with flame retardants addition.
The main drawbacks faced by researchers to successfully implement organic-PCM as materials to improve the thermal performance of building systems are their low thermal conductivity, their high flammability, and their low thermal cycling stability. In the present work, authors present a new enhanced PCM formulations aimed to solve the stated disadvantages in organic bulk-PCM. The new enhanced PCMs were prepared by adding high thermal conductivity particles and two kinds of flame retardants into organic PCM (paraffin and fatty acid eutectic mixtures). In the first stage, the effective thermal conductivity of organic-PCM was increased by using two different methods: directly dispersion of powder graphite (PG) bulk-PCM and vacuum impregnation of PCM into expanded graphite (EG). In the second stage, the fire reaction behaviour of the thermal conductivity enhanced PCM formulations was improved by adding two kind of flame retardants: magnesium hydroxide and ammonium phosphate (APP). Their fire reaction behaviour, thermal conductivity and thermophysical properties were measured by adapting the dripping test (UNE 23727-90), the hot-wire method and Differential Scanning Calorimetry (DSC), respectively. The enhanced PCM composites show a self-extinguished behaviour in terms of fire performance mechanism. The EG working with endothermic and phosphates flame retardants improve the fire performance of PCM by acting as a synergic system and the thermal conductivity is increased. However, their thermal storage capacity is significant decreased due to the large amount of flame retardant added (up to 40%). The thermal reliability was also tested, the enhanced PCM composites were stable up to 1000 thermal cycles.
2-Aminobenzylamine-based unsymmetrical salen-type Schiff base and its Cu (II), Ni (II), Co (II) and Fe (III) metal complexes were synthesized and their structures were investigated by various ...spectroscopic methods. The electropolymerization of the synthesized metal complexes were achieved on the graphite electrode. The electropolymerization process was conducted by cyclic voltammetry (CV) in a 0.15M LiClO4/Acetonitrile as supporting electrolyte medium. Characterization of the polymer coated electrodes were carried out by CV, SEM, EDX and UV–Vis techniques. The electrocatalytic activities of graphite electrodes modified with Schiff-base metal complex were investigated in the determination of compounds such as Dopamine (DA), Catechol (CC), Cysteine (Cys) and Uric Acid (UA). These studies showed that the salen-type Schiff base-Ni(II)-modified graphite electrode gave the best result in the determination of catechol and dopamine. Square wave voltammetry showed a linear response in the range of 0.09–0.35μM and 0.22–0.58μM with LoD of 0.03μM and 0.06μM for CC and DA, respectively.
Display omitted
•Unsymmetrical Schiff base metal complexes were synthesized.•Metal complexes were electropolymerized onto the graphite electrode.•New modified electrodes had catalytic activity on dopamine and catechol.•SWV showed a linear response in the range of 0.09–1μM with LoD of 0.03μM for catechol.
This book is the first of its kind to reflect upon the intense and rapidly growing interest in open geodesic polyaromatic molecules, specifically focusing on their synthesis and reactivity in metal ...binding reactions. The book broadly covers all aspects related to the fullerene fragment chemistry: current synthetic techniques, description of the available members of this new family (which has grown to more than two dozens members, with none being available commercially), molecular geometry and trends in the solid state packing, as well as extensions into physical properties and new buckybowl-based molecules and materials. It covers fundamental research related to a new class of hydrocarbons, namely open geodesic polyarenes that map onto the surfaces of fullerenes (and referred to as fullerene fragments or buckybowls.
Grafena merupakan satu lapis atom karbon yang memiliki hibridisasi sp2 membentuk struktur heksagonal dua dimensi. Grafena memiliki potensi yang sangat luas namun ketersediaannya masih terbatas. ...Penelitian ini bertujuan untuk mensintesis oksida grafena tereduksi (rGO) dari arang tempurung kelapa dengan menggunakan metode modifikasi Hummer. Modifikasi dilakukan dengan menghilangkan NaNO3. Sintesis dilakukan dengan ukuran partikel arang tempurung kelapa ~ 50 μm dan waktu oksidasi selama 5 hari. Analisis struktur rGO dilakukan dengan pengujian FTIR, UV-Vis dan difraksi sinar-X (XRD). Hasil pengujian FTIR menunjukkan adanya puncak pada panjang gelombang 1604,891 cm-1 dari ikatan C=C aromatik yang merupakan indikasi terbentuknya rGO. Hasil pengujian UV-Vis menunjukkan adanya serapan pada panjang gelombang 272 nm yang disebabkan oleh transisi π→π ⃰ dari ikatan C=C pada cincin aromatik. Pengujian XRD menghasilkan puncak difraktogram pada sudut 2θ ~ 24° yang khas untuk material rGO.
PDF
