Theoretical and experimental investigation of CO2 solubility in nanofluids containing NaP zeolite nanocrystals and [C12mim][Cl] ionic liquid

Today, CO₂ separation is very important, both as an environmental issue and also in various industries. In this study, the water-based nanofluid of NaP zeolite nanocrystals and 1-dodecyl-3-methylimidazolium chloride ([C₁₂mim][Cl]) ionic liquid were mixed and tested experimentally for CO₂ absorption in an isothermal high pressure cell equipped with magnetic stirring. Zeolite nanocrystals were synthesized via the hydrothermal approach and characterized. A series of experiments were performed at different conditions to investigate the impact of various parameters, including nanoparticle type, nanoparticle concentration, stabilizer concentration, and the vessel's initial pressure, on CO₂ solubility. It was found that 0.02 wt.% of zeolite nanoparticles, 0.4 wt.% of [C₁₂mim][Cl] ionic liquid, and 0.05 wt.% of sodium dodecyl benzene sulphonate (SDBS) in nanofluids result in higher absorption of CO₂ compared to other concentrations. Furthermore, CO₂ absorption was increased by increasing ionic liquid and surfactant concentration up to a certain value near critical micelle concentration, but after that the CO₂ absorption was decreased. The overall CO₂ absorption enhancement at 20 bar for 0.02 wt.% zeolite and ZnO water-based nanofluids with 0.4% [C₁₂mim][Cl] ionic liquid and 0.02 wt.% SDBS were 26.9%, 21.5%, 21.2%, and 17% in comparison to pure water, respectively. In an absorption process using nanofluids, besides the influence of the mentioned parameters, the micro-convection caused by Brownian motion and the grazing effect of nanoparticles should be noted. Considering the micro-convection and grazing effects, a theoretical model should take into account the Brownian motion and grazing effects on the mass transfer rate in nanofluids to investigate the absorption enhancement by nano-particles.     

Preparation of transparent PMMA/Fe(IO3)3 nanocomposite films from microemulsion polymerization

Polymethyl methacrylate (PMMA)/Fe(IO₃)₃ nanocomposite thin films are obtained by in situ particle generation in microemulsions and subsequent photopolymerization of a mixture containing methyl methacrylate, trimethylolpropane triacrylate, and crystallized iron iodate (Fe(IO₃)₃) nanorods. Hyper‐Rayleigh scattering measurements combined with X‐ray diffraction, transmission electron microscopy, and dynamic light scattering are first used to probe in situ the crystallization kinetics of iron iodate nanorods in water‐in‐oil microemulsions prepared with methyl methacrylate as the oil phase and marlophen NP12 as a surfactant. Trimethylolpropane triacrylate is then added as a crosslinker before spin‐coating. Films are deposited on glass substrates for the nonlinear optical characterizations and on silicon wafers for the piezoelectric and mechanical measurements. Nanocomposite films treated by corona discharge are finally characterized through optical microscopy, laser Doppler vibrometry, and Brillouin spectroscopy. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1203‐1211, 2013     

Nanocomposite piezoelectric films of P(VDF‐TrFE)/LiNbO3

Piezoelectric films were prepared by incorporation of lithium niobate (LiNbO₃) nanoparticles into copolymer of vinylidene difluoride and trifluoroethylene. Nanoparticles of LiNbO₃ with ferroelectric phase were successfully synthesized and dispersed homogenously by ultrasonication in the copolymer matrix without any surfactant or surface functionalization. The nanocomposites were fully characterized by electronic microscopy, X‐ray diffraction, differential scanning calorimetry, dynamical mechanical analysis, and piezometer. Surprisingly, the copolymer matrix crystallinity and morphology were not affected by the incorporation of nanoparticles. Therefore the nanocomposites remained good mechanicals properties and high ferroelectricity coupled to nonlinear optical activity thanks to the noncentro symmetric space group of lithium niobate. This could be a novel approach to develop new multifunctional materials. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Flame retardant polyurethane nanocomposite: Study of clay dispersion and its synergistic effect with dolomite

Polyurethane–clay nanocomposite adhesives were prepared by different synthetic routes and their microstructures were determined by X‐ray diffraction measurements and from transmission electron microscopy images. The preparation method of the polyurethane nanocomposite adhesives was systematically changed, that is, condensation either in the presence or absence of catalyst, concentration and type of nanoclay, premixing order of nanoclay (nanoclay was either premixed with the polyol or isocyanate part) and by using MDI surface treated nanoclays. Depending on the polymerization conditions cluster, intercalated, and exfoliated clay structures were obtained. The flame retardant properties of the manufactured nanocomposite adhesives and the synergistic effect of clay in combination with dolomite were investigated by cone calorimeter and UL 94 vertical burning tests. The results indicate that addition of nanoclay reduces burning time and the total heat evolved (THE) at flame out, and that the type of assembled clay structure (cluster, intercalated or exfoliated) had a significant effect on the flame retardant property. Nanocomposites with 3 wt % of clay loading gave the shortest burning time, the lowest THE and also UL 94 V‐2 ratings were reached, although the flame retardancy in terms of heat release rate and time to ignition was not improved. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Essential work of fracture of poly(ϵ‐caprolactone)/boehmite alumina nanocomposites: Effect of surface coating

The essential work of fracture (EWF) approach was adopted to reveal the effect of nanofillers on the toughness of poly (?‐caprolactone) (PCL)/boehmite alumina (BA) nanocomposites. Synthetic BA particles with different surface treatments were dispersed into the PCL matrix by extrusion melt compounding. The morphology of the composites was studied by scanning electron microscopy. Differential scanning calorimetry and wide‐angle X‐ray scattering were used to detect changes in the crystalline structure of PCL. Also, mode I type EWF tests, dynamic mechanical analysis, and quasi‐static tensile tests were applied to study the effect of the BA nanofillers on the mechanical properties of the nanocomposites. BA was homogeneously dispersed and acted as heterogeneous crystallization nucleant and a nonreinforcing filler in PCL. The tensile modulus and yield strength slightly increased and the yield strain decreased with increasing BA content (up to 10 wt %). The effect of the BA surface treatment with octylsilane was negligible by contrast to that with alkylbenzene sulfonic acid (OS2). Like the tensile mechanical data, the essential and nonessential work of fracture parameters did not change significantly either. The improved PCL/BA adhesion in case of OS2 treatment excluded the usual EWF treatise. This was circumvented by energy partitioning between yielding and necking. The yielding‐related EWF decreased, whereas the nonessential EWF increased with BA content and with better interfacial adhesion. This was attributed to the effect of matrix/filler debonding. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Semiconductor/Polymer Nanocomposites of Acrylates and Nanocrystalline Silicon by Laser‐Induced Thermal Polymerization

In this work, a novel method for the preparation of polymer/semiconductor nanocomposites is presented. The nanocomposite is directly prepared from a suspension of nanocrystalline silicon (nc‐Si) in bulk vinyl monomers (acrylates) and focused heating of the nc‐Si by irradiation with a pulsed laser at 532 nm wavelength. The silicon nanocrystals are the inorganic component of the composite and simultaneously act as initiation points of the free radical polymerization forming the hybrid composite. By this method, patterned nanocomposite films with thicknesses up to ≈250 µm can be readily prepared. Furthermore, the polymerization kinetics were investigated for different reaction conditions such as irradiation time, laser intensity, nc‐Si content, and addition of radical initiators.

     

含CaF2纳米晶的透明玻璃陶瓷的制备工艺分析

采用熔融冷却法制备了组分为55SiO2-20Al2O3-5CaO-20CaF2及45SiO2-20Al2O3-10CaO-25CaF2两组玻璃,并通过热分析测定了玻璃的转变温度、核化温度和晶化温度。采取等温热处理工艺在不同温度下对两组玻璃进行3h晶化热处理并对热处理后的试样进行物相结构、透光率和微观形貌的表征。结果表明,将玻璃进行等温晶化热处理能制备含CaF2纳米晶的透明玻璃陶瓷;增加组分中CaF2及CaO的含量能提高体系的玻璃转变温度及成核温度;提高热处理温度使析晶程度增大,透光率下降;CaF2和CaO在玻璃中可引起成分偏聚而产生分相,提高玻璃的析晶程度。     

Effect of protein adsorption on cell uptake and blood clearance of methoxy poly(ethylene glycol)‐poly(caprolactone) nanoparticles

The interactions between nanoparticles and cells or tissues are frequently mediated by different biomolecules adsorbed onto the surface of nanoparticles. In this study, several methoxy poly(ethylene glycol)‐poly(ε‐caprolactone) (mPEG‐PCL) copolymers with various mPEG/PCL ratios were synthesized and used to produce three types of mPEG‐PCL nanoparticles. The protein‐adsorption behavior of nanoparticles was assessed using fetal‐bovine‐serum (FBS) as a model protein. The cell uptake of nanoparticles at different nanoparticle doses as well as various culture periods was examined by measuring their endocytosis rate related to Hela cells cultured in FBS‐free and FBS‐contained media. The blood clearance of nanoparticles was evaluated using Kunming mice to see the differences in circulation durations of nanoparticles. Results suggest that that FBS is able to significantly regulate the cell uptake of nanoparticles in vitro, and on the other hand, the size and mPEG/PCL molar ratio of mPEG/PCL nanoparticles are closely correlated to their blood clearance. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42884.     

Conducting polymerized high‐internal‐phase emulsion/single‐walled carbon nanotube nanocomposite foams: Effect of the aqueous‐phase surfactant type on the morphology and conductivity

Poly(styrene‐co‐divinylbenzene)/single‐walled carbon nanotubes (SWCNTs) polymerized high‐internal‐phase emulsion (polyHIPE) nanocomposite foams were successfully synthesized with various types of aqueous‐phase surfactants. The effects of anionic, cationic, nonionic, and mixed surfactants on the morphology and electrical conductivity of the resulting nanocomposite foams were investigated. The use of an anionic surfactant, sodium dodecylbenzesulfonate (SDBS), did not completely result in the typical polyHIPE nanocomposite foam microstructure because of the partial instability of the high‐internal‐phase emulsion. The nanocomposite foams synthesized by nonionic surfactants, that is, Pluronic F127 and Triton X‐100, and the cationic/anionic mixture, cetyltrimethylammonium bromide/SDBS, exhibited the proper morphology, but the resulting nanocomposite foams were electrically insulators. Interestingly, the use of a Gemini‐like surfactant, sodium dioctylsulfosuccinate (SDOSS), significantly improved both the typical morphology and electrical properties of the resulting nanocomposite foams because of the probable stronger interactions of SDOSS molecules with SWCNTs. The typical morphology of the nanocomposite foam synthesized with the SDOSS/F127 mixed surfactant was significantly improved, but the electrical conductivity decreased to some extent compared with the SDOSS‐synthesized nanocomposite foams. This behavior was attributed to an increase in the tunneling length of the electrons between adjacent SWCNTs. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43883.