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chemistry. nanocomposite

Lenka Vaculíková, Eva Plevová, Michal Ritz
The detailed structural chemistry of clay minerals is an important aspect of polymer-clay nanocomposite research. A variety of analytical methods are currently available for material characterization. Keep in mind, however, that each method has some limitations. The best results are usually achieved by a combination of several analytical methods. The contribution demonstrates the potential and applicability of infrared and Raman spectroscopy in identification and structural characterization of montmorillonites...
May 1, 2019: Journal of Nanoscience and Nanotechnology
Yanyang Zhang, Xinwei She, Xiang Gao, Chao Shan, Bing-Cai Pan
Polystyrene-based nano-ferric oxide composite is a representative nanomaterial successfully applied in scale-up water decontamination for arsenic and phosphorous. However, little is available on the effect of solution chemistry (for instance, the coexisting Ca2+) on long-term performance of the nanocomposite. In this study, we carried out 20 cyclic runs of phosphate adsorption-desorption on a polymer-supported ferric nanocomposite HFO@201. Unexpectedly, an enhanced phosphate removal was observed in the presence of Ca2+, which is quite different from its adverse effect on phosphate capture by granular ferric oxide...
November 27, 2018: Environmental Science & Technology
Moo-Kwang Shin, Myeong-Hoon Kim, Ga-Yun Kim, Byunghoon Kang, Joo Seung Chae, Seungjoo Haam
The precise control of sensitivity to external stimuli, e.g., impact, friction, and thermal energy, has been emphasized for highly energetic materials, including RDX and HMX. Such sensitivities could be controlled by adjusting the surface area or (in)organic additives however, increased stability leads to a decrease in the explosives' performance. Here, high-energy-density molecules hosted in inverse opal-like porous carbon (IOC) nanocomposites demonstrate the mechanical stabilization and desensitization of RDX and HMX inside the carbon nanostructure using host-guest chemistry techniques...
November 26, 2018: ACS Applied Materials & Interfaces
Qinglan Zhao, Dongfang Yang, Cheng Zhang, Xuanhe Liu, Xin Fan, Andrew K Whittaker, Xiu Song Zhao
Redox-active polyimide materials hold a great promise for electrochemical energy storage applications, especially for flexible energy storage devices. However, the low utilisation efficiency due to poor electrical conductivity of the materials remains one of the greatest challenges. In this work, we designed and prepared polyimide-graphene composite materials and tested their electrochemical properties in sodium-ion capacitors. By manipulating the interfacial chemistry and interactions between the polyimide and graphene, composite electrode materials with different polyimide particle sizes and morphologies were obtained...
November 26, 2018: ACS Applied Materials & Interfaces
Sara Politi, Rocco Carcione, Emanuela Tamburri, Roberto Matassa, Teresa Lavecchia, Mariglen Angjellari, Maria Letizia Terranova
We report here on soft-template electropolymerizations of polypyrrole (Ppy)-based nanocomposites triggered by graphene platelets (GP) from shungite (SH) rocks. A properly designed procedure for an efficient extraction of graphene platelets from SH powders is established to produce remarkable graphene materials in a low oxidation state and with a high electrical conductivity (1490 S cm-1 ). By using positively and negatively charged templating surfactants the role played by the graphene units on the electropolymerization reactions is pointed out by SEM, EDX, TEM, SAED, XPS and Raman spectroscopy...
November 19, 2018: Scientific Reports
Elisabetta Campodoni, Ellinor B Heggset, Ahmad Rashad, Gloria B Ramírez-Rodríguez, Kamal Mustafa, Kristin Syverud, Anna Tampieri, Monica Sandri
Biopolymers such as gelatin (Gel) and cellulose nanofibrils (CNF) have many of the essential requirements for being used as scaffolding materials in tissue regeneration; biocompatibility, surface chemistry, ability to generate homogeneous hydrogels and 3D structures with suitable pore size and interconnection, which allows cell colonization and proliferation. The purpose of this study was to investigate whether the mechanical behaviour of the Gel matrix can be improved by means of functionalization with cellulose nanofibrils and proper cross-linking treatments...
January 1, 2019: Materials Science & Engineering. C, Materials for Biological Applications
Fernan Saiz, Nick Quirke
We have used ab initio molecular dynamics and density-functional theory (DFT) calculations at the B3LYP/6-31G** level of theory to evaluate the energy and localisation of excess electrons at a number of representative interfaces of polymer nanocomposites. These modelled interfaces are made by combining liquid water and amorphous slabs of polyethylene and silica. The walls of the amorphous silica slabs are built with two surface chemistries: Q4 or fully-dehydroxylated and Q3/Q4 or partially-hydroxylated with a silanol content between 1...
November 7, 2018: Physical Chemistry Chemical Physics: PCCP
Marion J Limo, Anna Sola-Rabada, Estefania Boix, Veeranjaneyulu Thota, Zayd C Westcott, Valeria Puddu, Carole C Perry
Metallo-oxide (MO)-based bioinorganic nanocomposites promise unique structures, physicochemical properties, and novel biochemical functionalities, and within the past decade, investment in research on materials such as ZnO, TiO2 , SiO2 , and GeO2 has significantly increased. Besides traditional approaches, the synthesis, shaping, structural patterning, and postprocessing chemical functionalization of the materials surface is inspired by strategies which mimic processes in nature. Would such materials deliver new technologies? Answering this question requires the merging of historical knowledge and current research from different fields of science...
November 28, 2018: Chemical Reviews
Zhouli Wang, Xueke Li, Yuejuan Zhao, Yahong Yuan, Rui Cai, Tianli Yue
An approach based on multifunctional fluorescent magnetic nanoparticles was proposed for the enrichment and identification of Alicyclobacillus spp. in apple juice simultaneously. The prepared Fe3 O4 magnetic particles (MNPs) were modified by the sol-gel process and a silica shell was formed to improve the reactivity, and then the obtained MNPs@SiO2 -SH nanoparticles were conjugated with Thioglycolic acid functionalized CdTe/CdS QDs via thiols chemistry. The characteristic evaluation results indicated that the MNPs-QD nanocomposites exhibited good magnetic properties and optical characterization...
December 2018: Food Research International
Mihyun Lee, Kraun Bae, Pierre Guillon, Jin Chang, Oystein Arlov, Marcy Zenobi-Wong
3D bioprinting allows the fabrication of 3-dimensional (3D) structures containing living cells whose 3D shape and architecture are matched to a patient. The feature is desirable to achieve personalized treatment of trauma or diseases. However, realization of this promising technique in the clinic is greatly hindered by inferior mechanical properties of most biocompatible bioink materials. Here, we report a novel strategy to achieve printing large constructs with high printing quality and fidelity using an extrusion-based printer...
October 15, 2018: ACS Applied Materials & Interfaces
Jun Jiang, Jinzhen Cao, Wang Wang, Changtong Mei
Silica/montmorillonite (MMT) nanocomposites (SMCs) were prepared by generating SiO₂ nanoparticles on an MMT surface using an organic/inorganic hybrid technique with different ratios of tetraethylorthosilicate (TEOS) to MMT (10:1, 20:1 and 40:1). The hydrolysis and polycondensation reactions were controlled by TEOS when it was incorporated into the internal space of the MMT. The delamination and intercalation of the MMT layers were closely related to the TEOS/MMT ratio. The surface chemistry and particulate morphology, thermal properties, pore structure and hygroscopicity of nanocomposites were investigated...
October 24, 2018: Materials
Xiaoqing Cui, Hong Zhao, Zengxi Li
Abnormal concentration of hydrogen peroxide (H2 O2 ) in blood plasma and cells may lead to several diseases. Thus, it is important to develop a selective and sensitive method to monitor H2 O2 . In the present work, a novel nonenzymatic H2 O2 -sensing platform based on cobalt oxyhydroxide (CoOOH)/reduced graphene oxide (RGO) nanocomposite was fabricated. CoOOH nanoflakes were firstly synthesized via soft chemistry routes and then assembled on the surface of RGO. A series of characterizations by X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy demonstrated that hexagonal CoOOH nanoflakes were well distributed on the surface of RGO...
November 2018: Analytical and Bioanalytical Chemistry
Sandra S Gkermpoura, Konstantinia D Papadimitriou, Emmanuel N Skountzos, Ioannis Polyzos, Maria Giovanna Pastore Carbone, Athanasios Kotrotsos, Vlasis G Mavrantzas, Costas Galiotis, Constantinos Tsitsilianis
3-Arm PMMAs end-functionalized by pyrene were designed as dispersing/stabilizing agents for the liquid-phase exfoliation of graphite in low-boiling point solvents like chloroform. The synthetic procedure comprised ARGET ATRP controlled polymerization, click chemistry and the quaternization reaction of triazole, ensuring tailor-made, well-defined pyrene-functional star PMMAs. Among a series of different pyrene-functional macromolecular topologies, the (PMMA-py2)3 proved the most efficient exfoliation agent giving relatively high graphene concentration (0...
October 9, 2018: Nanoscale
Kizkitza González, Clara García-Astrain, Arantzazu Santamaria-Echart, Lorena Ugarte, Luc Avérous, Arantxa Eceiza, Nagore Gabilondo
Starch-based hydrogels were performed by Diels-Alder cross-linking reactions between furan-modified starch and a water soluble bismaleimide, with improving conducting properties by using graphene layers as active nanofillers. The characterization results demonstrated that the Diels-Alder reaction and the corresponding conditions for the hydrogel formation were appropriate. The effect of increasing the furan/maleimide ratio on the architecture of the hydrogels and on the morphological, rheological and swelling properties were thoroughly evaluated...
December 15, 2018: Carbohydrate Polymers
S Rößler, C Heinemann, B Kruppke, A S Wagner, S Wenisch, H P Wiesmann, T Hanke
The intent of the present study was to demonstrate that multiphasic silica/collagen xerogels are able to manipulate cellular processes. These xerogels were prepared by a sol-gel approach allowing the incorporation of mineral phases. The resulting nanocomposites are designed as biomaterial for bone regeneration. Human osteoclasts derived from peripheral blood mononuclear cells were cultured both indirectly and directly, either in presence of different xerogel types or on their surface, to investigate the factor with the main influence on osteoclastogenesis...
December 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
Jegan Athinarayanan, Vaiyapuri Subbarayan Periasamy, Rajapandiyan Krishnamoorthy, Ali A Alshatwi
Graphene nanocomposites have received attention for the therapy and detection of diseases. In this study, we developed a simple and green chemistry approach for synthesizing Cu2 O/graphene nanocomposites (Cu2 O/G) using date palm fruit syrup as a reducing agent. The graphene oxide surface anchored with Cu(OH)2 and reduced it to fabricate Cu2 O-anchored graphene nanosheets using date palm fruit syrup. Physicochemical characteristics of the synthesized nanocomposites were analyzed. Scanning electron microscopy images revealed 50-70 nm Cu2 O nanostructures anchored on the surface of crumpled graphene sheets...
December 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
Allison Jansto, Eric M Davis
While the introduction of nanoparticles into Nafion membranes has proven to be a viable method to tune the ion selectivity in energy storage technologies such as the vanadium redox flow battery, there still remains a limited understanding of the fundamental mechanism by which the nanoparticles selectively restrict ion crossover. Herein, the surface chemistry and loading of SiO2 nanoparticles (SiNPs) were systematically varied to elucidate the relationship between nanoparticle dispersion (or dispersion state) and vanadium ion permeability in Nafion nanocomposite membranes...
October 24, 2018: ACS Applied Materials & Interfaces
Asieh Soozanipour, Asghar Taheri-Kafrani
Enzymes are used as biocatalysts for analytical purposes in diagnostics and preparative purposes in large-scale industrial processes. Despite perfect catalytic properties of enzymes, their industrial applications are limited due to the drawbacks regarding the lack of long-term stability under process conditions. The difficulties associated with recycling have to be resolved before enzyme implementation at industrial scale. Enzyme immobilization, as a novel approach, can improve the half-life, stability, catalytic activity, and reusability of enzymes...
2018: Methods in Enzymology
Ashwaq A Al-Hashedi, Marco Laurenti, Mohamed Amine Mezour, Tayebeh Basiri, Heithem Touazine, Mohamed Jahazi, Faleh Tamimi
Oral hygiene and regular maintenance are crucial for preserving good peri-implant health. However, available prophylaxis products and toothpastes, which are optimized for cleaning teeth, tend to contaminate and abrade implant surfaces due to their organic components and silica microparticles, respectively. This study aims to develop an organic-free implant-paste based on two-dimensional nanocrystalline magnesium phosphate gel and hydrated silica nanoparticles (20-30% w/w) for cleaning oral biofilm on titanium dental implants...
September 8, 2018: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
Khouloud Jlassi, A Bahgat Radwan, Kishor Kumar Sadasivuni, Miroslav Mrlik, Aboubakr M Abdullah, Mohamed M Chehimi, Igor Krupa
Epoxy polymer nanocomposites filled with magnetite (Fe3 O4 ) clay (B), named (B-DPA-PANI@Fe3 O4 ) have been prepared at different filler loading (0.1, 0.5, 1, 3, 5 wt. %). The surface modification of clay by polyaniline (PANI) is achieved in the presence of 4-diphenylamine diazonium salt (DPA). The effects of the nanofiller loading on Tensile, mechanical and dielectric properties were systematically studied. Improved properties was highlighted for all reinforced samples. The addition of only 3 wt. % of the filler enhanced the tensile strength of the composites by 256%, and the glass transition temperature Tg by 37%...
September 6, 2018: Scientific Reports
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