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Anabel Palacios, Alvaro De Gracia, Laia Haurie, Luisa F Cabeza, A Inés Fernández, Camila Barreneche
The implementation of organic phase change materials (PCMs) in several applications such as heating and cooling or building comfort is an important target in thermal energy storage (TES). However, one of the major drawbacks of organic PCMs implementation is flammability. The addition of flame retardants to PCMs or shape-stabilized PCMs is one of the approaches to address this problem and improve their final deployment in the building material sector. In this study, the most common organic PCM, Paraffin RT-21, and fatty acids mixtures of capric acid (CA), myristic acid (MA), and palmitic acid (PA) in bulk, were tested to improve their fire reaction...
January 12, 2018: Materials
Jacek Lubczak, Renata Lubczak, Iwona Zarzyka
The one-pot multicomponent synthesis of oligoetherols containing azacycles is described. They were obtained by reaction of isocyanuric, barbituric, or uric acid or melamine with glycidol and alkylene carbonates. The isolated products were characterized by physical methods and their properties were compared with the same compounds obtained in twostep protocol. The oligoetherols with 1,3,5-triazine ring obtained by both methods were then used to form polyurethane foams and their properties were compared.
December 2017: Acta Chimica Slovenica
Tianyu Zhou, Jie Ding, Qiang Wang, Yuan Xu, Bo Wang, Li Zhao, Hong Ding, Yanhua Chen, Lan Ding
Monodisperse superhydrophilic melamine formaldehyde resorcinol resin (MFR) microspheres were prepared in 90min at 85°C via a microwave-assisted method with a yield of 60.6%. The obtained MFR microspheres exhibited narrow size distribution with the average particle size of about 2.5µm. The MFR microspheres were used as absorbents to detect triazines in juices followed by high performance liquid chromatography tandem mass spectrometry. Various factors affecting the extraction efficiency were investigated. Under the optimized conditions, the built method exhibited excellent linearity in the range of 1-250μgL-1 (R2 ≥ 0...
March 1, 2018: Talanta
Xiaolan Wang, Juntao Wang, Caina Jiao, Lin Hao, Qiuhua Wu, Chun Wang, Zhi Wang
A magnetic mesoporous poly-melamine-formaldehyde composite (M-mPMF) was synthesized by covalent grafting of poly-melamine-formaldehyde onto NH2-Fe3O4 surface. The M-mPMF was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and nitrogen adsorption-desorption isotherms. The result shows that the M-mPMF possesses a high porosity, large surface area and strong magnetism. The extraction performance of the M-mPMF was investigated by using it as the magnetic adsorbent for the extraction of chlorophenols from pond water and honey samples prior to high performance liquid chromatographic analysis...
March 1, 2018: Talanta
Wilhelm Maximilian Hützler, Michael Bolte
Doubly and triply hydrogen-bonded supramolecular synthons are of particular interest for the rational design of crystal and cocrystal structures in crystal engineering since they show a high robustness due to their high stability and good reliability. The compound 5-methyl-2-thiouracil (2-thiothymine) contains an ADA hydrogen-bonding site (A = acceptor and D = donor) if the S atom is considered as an acceptor. We report herein the results of cocrystallization experiments with the coformers 2,4-diaminopyrimidine, 2,4-diamino-6-phenyl-1,3,5-triazine, 6-amino-3H-isocytosine and melamine, which contain complementary DAD hydrogen-bonding sites and, therefore, should be capable of forming a mixed ADA-DAD N-H...
January 1, 2018: Acta Crystallographica. Section C, Structural Chemistry
Y Lou, D F Shantz
The role of different nitrogen atoms in melamine dendrons tethered to SBA-15 is elucidated. For the nitroaldol (Henry) reaction all nitrogen atoms of the capping group participate in the reaction. For metal binding, uptake correlates with the diamine content indicating interior amines are accessible. Carbon dioxide uptake properties are dictated by the presence of the peripheral amines with little interior contribution. The results show that different nitrogen atoms contribute to different processes including catalysis, metal sequestration, and gas separations...
January 4, 2018: Chemical Communications: Chem Comm
Bing Liu, Liqun Ye, Ran Wang, Jingfeng Yang, Yuexing Zhang, Rong Guan, Lihong Tian, Xiaobo Chen
Phosphorus-doped graphitic carbon nitrides (P-g-C3N4) have recently emerged as promising visible-light photocatalysts for both hydrogen generation and clean environment applications, due to a fast charge carriers transfer and an increased light absorption. However, their photocatalytic performances on CO2 reduction gain little attention. In this work, phosphorus-doped g-C3N4 nanotubes are synthesized through one-step thermal reaction of melamine and sodium hypophosphite monohydrate (NaH2PO2H2O). The phosphine gas from the thermal-decomposition of NaH2PO2H2O induces the formation of P-g-C3N4 nanotubes from g-C3N4 nanosheets, leads to an enlarged BET surface area and a unique mesoporous structure, and creates an amino-rich surface...
December 26, 2017: ACS Applied Materials & Interfaces
Evan Call, Brian Bill, Chad McLean, Nathan Call, Allyn Bernkopf, Craig Oberg
Background: Hazardous drug contamination (HD) in healthcare environments continues, placing healthcare staff at risk of significantly chronic health problems, despite the use of personal protective equipment (PPE) and closed system transfer device systems (CSTDs). Objective: This study's aim was to determine how HD might spread through touch after handling contaminated vials in simulated pharmacy and nursing environments. Methods: UV fluorescent powder Glo Germ (Glo Germ Co., Moab, UT), composed of melamine resin, was used to simulate HD...
September 2017: Hospital Pharmacy
Duihai Tang, Kuo Li, Wenting Zhang, Zhen-An Qiao, Junjiang Zhu, Zhen Zhao
A series of Co nanoparticles embedded, N-doped mesoporous carbons have been synthesized through chelate-assisted co-assembly strategy followed by thermal treatment. The preparation is based on an assembly process, with evaporation of an ethanol-water solution containing melamine formaldehyde resin (MF resin) as carbon source, nitrogen source, and chelating agent. Moreover, F127 and Co(NO3)2 are used as template and metallic precursor, respectively. The Co nanoparticles embedded, N-doped mesoporous carbon annealed at 800 °C (denoted as MFCo800) shows high electrocatalytic activity for hydrogen evolution reaction (HER) with high current density and low overpotential, which has the ability to operate in both acidic and alkaline electrolytes...
December 11, 2017: Journal of Colloid and Interface Science
Marta Sevilla, Abdul Salam M Al-Jumialy, Antonio B Fuertes, Robert Mokaya
A versatile chemical activation approach for the fabrication of sustainable porous carbons with a pore network tunable from micro- to hierarchical micro-/mesoporous is hereby presented. It is based on the use of a less corrosive and less toxic chemical, i.e. potassium oxalate, than the widely used KOH. The fabrication procedure is exemplified for glucose as precursor, although it can be extended to other biomass derivatives (saccharides) with similar results. When potassium oxalate alone is used as activating agent, highly microporous carbons are obtained (SBET ~ 1300 - 1700 m2 g-1)...
December 20, 2017: ACS Applied Materials & Interfaces
Shuo Zhang, Lina Sui, Hongquan Kang, Hongzhou Dong, Lifeng Dong, Liyan Yu
Nitrogen-doped graphene (NG) with wrinkled and bubble-like texture is fabricated by a thermal treatment. Especially, a novel sonication-assisted pretreatment with nitric acid is used to further oxidize graphene oxide and its binding with melamine molecules. There are many bubble-like nanoflakes with a dimension of about 10 nm appeared on the undulated graphene nanosheets. The bubble-like texture provides more active sites for effective ion transport and reversible capacitive behavior. The specific surface area of NG (5...
December 18, 2017: Small
Mohammed M Rahman, Jahir Ahmed
Cadmium doped antimony oxide (Cd-doped Sb2O4) nanostructures (CAO-NSs) were synthesized by a facile hydrothermal method in alkaline phase at low temperature to detect the melamine from aqueous solution. The calcined CAO-NSs were characterized systematically by FE-SEM, EDS, UV/Vis., FTIR spectroscopy, powder XRD, and XPS techniques. The glassy carbon electrode (GCE) was modified with the CAO-NSs and sensing performance towards the selective melamine was explored by the electrochemical approach in phosphate buffer solution...
December 7, 2017: Biosensors & Bioelectronics
Fulai Qi, Zhangxun Xia, Jutao Jin, Xudong Fu, Wei Wei, Suli Wang, Gongquan Sun
Due to the unique structure, carbon aerogels have always shown great potential for multifunctional applications. At present, it is highly desirable but remains challenging to tailor the micro-structures in respect of porosity and specific surface area to further expand its significance. A facile chemical foaming coupled self-etching strategy is developed for multiscale processing of carbon aerogels. The strategy is directly realized via the pyrolysis of a multifunctional precursor (pentaerythritol melamine phosphate) without any special drying process and multiple steps...
December 11, 2017: ACS Applied Materials & Interfaces
Benjamin A Vervaet, Patrick C D'Haese, Anja Verhulst
Human beings are exposed to various potentially toxic agents and conditions in their natural and occupational environments. The kidney, due to its concentrating ability and excretory function, is highly vulnerable to the effects of environmental toxins. Identifying the precise cause and mechanisms of environmentally induced renal injury remains a challenge for which various scientific disciplines need to be involved. Investigations in this field are confronted with the apparent infinite types of toxins, their mutual interaction, handling/metabolization by the body, ways of exposure, etc...
December 2017: Clinical Kidney Journal
Aditya Farhan Arif, Yuma Kobayashi, Elia Michael Schneider, Samuel C Hess, Ratna Balgis, Takafumi Izawa, Hideharu Iwasaki, Shuto Taniguchi, Takashi Ogi, Kikuo Okuyama, Wendelin J Stark
Monodisperse, nitrogen-doped hollow carbon spheres of submicron size were synthesized using hexamethoxymethyl melamine as both a carbon and nitrogen source in a short (1 h) microwave-assisted synthesis. After carbonization at 550 °C, porous carbon spheres with a remarkably high nitrogen content of 37.1% were obtained, consisting mainly of highly basic pyridinic moieties. The synthesized hollow spheres exhibited high selectivity for carbon dioxide (CO2) over nitrogen and oxygen gases, with a capture capacity up to 1...
December 7, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Jakub Krajniak, Zidan Zhang, Sudharsan Pandiyan, Eric Nies, Giovanni Samaey
We present a comprehensive approach for reverse mapping of complex polymer systems in which the connectivity is created by the simulation of chemical reactions at the coarse-grained scale. Within the work, we use a recently developed generic adaptive reverse mapping procedure that we adapt to handle the varying connectivity structure resulting from the chemical reactions. The method is independent of the coarse-grained and fine-grained force-fields by design and relies only on a single control parameter. We employ the approach to reverse map four different systems: a three-component epoxy network, a trimethylol melamine network, a hyperbranched polymer, and a polyethylene terephthalate...
December 6, 2017: Journal of Computational Chemistry
Erkan Halay, Selahattin Bozkurt
Hydrogen bonding and π-π interactions take special part in the enantioselectivity task. In this regard, because of having both hydrogen acceptor and hydrogen donor groups, melamine derivatives become more of an issue for enantioselectivity. In the light of such information, triazine-based chiral, fluorescence active novel thiazole derivatives L1 and L2 were designed and synthesized from (S)-(-)-2-amino-1-butanol and (1S,2R)-(+)-2-amino-1,2-diphenylethanol. The structural establishment of these compounds was made by spectroscopic methods such as FTIR, 1 H, and 13 C NMR...
December 6, 2017: Chirality
Javier Pinto, Athanassia Athanassiou, Despina Fragouli
In the last decade, a continuous increasing research activity is focused on the surface functionalization of polymeric porous materials for the efficient removal of oil contaminants from water. This work reviews the most significant recent studies on the functionalization of polyurethane and melamine foams, materials commonly reported for oil-water separation applications. After the identification of the key features of the foams required to optimize their oil removal performance, a wide variety of physicochemical treatments are described together with their effect on the oil absorption selectivity and oil absorption capacity, both critical parameters for the application of the foams in the remediation of oil spills...
December 1, 2017: Journal of Environmental Management
Shuilai Qiu, Chao Ma, Xin Wang, Xia Zhou, Xiaming Feng, Richard K K Yuen, Yuan Hu
To achieve superior fire safety epoxy resins (EP), a novel multifunctional organic-inorganic hybrid, melamine-containing polyphosphazene wrapped ammonium polyphosphate (PZMA@APP) with rich amino groups was prepared and used as an efficient flame retardant. Thanks to the cross-linked polyphosphazene part, PZMA@APP exhibited high flame retardant efficiency and smoke suppression to the EP composites. Thermogravimetric analysis indicated that PZMA@APP significantly enhanced the thermal stability of EP composites...
November 20, 2017: Journal of Hazardous Materials
Vladimir V Korolkov, Matteo Baldoni, Kenji Watanabe, Takashi Taniguchi, Elena Besley, Peter H Beton
Two-dimensional (2D) supramolecular arrays provide a route to the spatial control of the chemical functionality of a surface, but their deposition is in almost all cases limited to a monolayer termination. Here we investigated the sequential deposition of one 2D array on another to form a supramolecular heterostructure and realize the growth-normal to the underlying substrate-of distinct ordered layers, each of which is stabilized by in-plane hydrogen bonding. For heterostructures formed by depositing terephthalic acid or trimesic acid on cyanuric acid/melamine, we have determined, using atomic force microscopy under ambient conditions, a clear epitaxial arrangement despite the intrinsically distinct symmetries and/or lattice constants of each layer...
December 2017: Nature Chemistry
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