Monodisperse crosslinked polystyrene(PS) hollow core microspheres were successfully synthesized by two-step dispersion polymerization. The effects of the reaction parameters such as the crosslinking agent concentratio...
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Monodisperse crosslinked polystyrene(PS) hollow core microspheres were successfully synthesized by two-step dispersion polymerization. The effects of the reaction parameters such as the crosslinking agent concentration, the initiator concentration and the monomer concentration on the particle sizes and size distribution were investigated. The results demonstrated that when the crosslinking agent concentration was low, the hollow microspheres had serious collapse, while the polymer particles became polydisperse with highly concentrated crosslinking agent. When increasing the initiator concentrations, particles with larger sizes and wider size distribution were obtained. If the initial monomer(styrene) weight fraction was too low, the honeycomb hollow ball or even solid particles would be formed, while if the monomer concentration was too high, the hollow microspheres appeared collapsed or ruptured.
We used both correlation and covariance-principal component analysis (PCA) to classify the same absorption-reflectance data collected from 13 different polymeric fabric materials that was obtained using Attenuated Tot...
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We used both correlation and covariance-principal component analysis (PCA) to classify the same absorption-reflectance data collected from 13 different polymeric fabric materials that was obtained using Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR). The application of the two techniques, though similar, yielded results that represent different chemical properties of the polymeric substances. On one hand, correlation-PCA enabled the classification of the fabric materials according to the organic functional groups of their repeating monomer units. On the other hand, covariance-PCA was used to classify the fabric materials primarily according to their origins;natural (animal or plant) or synthetic. Hence besides major chemical functional groups of the repeat units, it appears covariance-PCA is also sensitive to other characteristic chemical (inorganic and/or organic) or biochemical material inclusions that are found in different samples. We therefore recommend the application of both covariance-PCA and correlation-PCA on datasets, whenever applicable, to enable a broader classification of spectroscopic information through data mining and exploration.
Nanofiber-based membranes were prepared by two different methods for use as separators for Lithium-ion batteries (LIBs). In the first method, Electrospinning was used for the fabrication of Polyvinylidene fluoride PVD...
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Nanofiber-based membranes were prepared by two different methods for use as separators for Lithium-ion batteries (LIBs). In the first method, Electrospinning was used for the fabrication of Polyvinylidene fluoride PVDF nanofiber coatings on polyolefin microporous membrane separators to improve their electrolyte uptake and electrochemical performance. The nanofiber-coated membrane separators show better electrolyte uptake and ionic conductivity than that for the uncoated membranes. In the second method, Forcespinning® (FS) was used to fabricate fibrous cellulose membranes as separators for LIBs. The cellulose fibrous membranes were made by the Forcespinning® of a cellulose acetate solution precursor followed by a subsequent alkaline hydrolysis treatment. The results show that the fibrous cellulose membrane-based separator exhibits high electrolyte uptake and good electrolyte/electrode wettability and therefore can be a good candidate for high performance and high safety LIB separators.
The design and fabrication of multi-layer amperometric electrochemical glucose sensors is dependent upon the diffusional kinetics of the chemical/biochemical species which contribute to the sensor's response. Cons...
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Halogen-free flame retardant applications attract great interest of industry as well as of research. Most commercial available flame retardants for polypropylene have to be used with high filler loading, which leads t...
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ISBN:
(纸本)9781634397087
Halogen-free flame retardant applications attract great interest of industry as well as of research. Most commercial available flame retardants for polypropylene have to be used with high filler loading, which leads to difficulties in processability, poor mechanical properties and unfavorable cost performance. Therefore it is important to gain fundamental knowledge about synergistic combinations of flame retardants and filler to reduce all disadvantages. In this research the combustion and burning behavior of expandable graphite polypropylene compounds with various mineral fillers were investigated. The results of the burning and combustion characterization were different and also partly contradicting. Combined compounds with EG and additional fillers obtain good results for protecting the material against combustion, while compounds filled with expandable graphite, layered silicates or zeolite show good protection against burning.
The activated carbon was prepared by the two-steps carbonization -activation process with printed circuit board(PCB), using KOH, K2CO3, NaOH and Na2CO3 as activators. The influence of temperature, reaction time and th...
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ISBN:
(纸本)9783038353300
The activated carbon was prepared by the two-steps carbonization -activation process with printed circuit board(PCB), using KOH, K2CO3, NaOH and Na2CO3 as activators. The influence of temperature, reaction time and the ratio between activator and material on methylene blue value was discussed. Box-behnken design was applied using Design-Expert software to optimize the conditions of preparation according to Response Surface Methodology(RSM).Results showed that activated carbon prepared by chemical activation with KOH or NaOH achieved higher adsorption of methylene blue.
Centrifugal spinning is a simple and versatile technique for producing nanofibers from various materials. One major application of centrifugal spinning is to produce advanced functional nanofibers for energy storage. ...
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Centrifugal spinning is a simple and versatile technique for producing nanofibers from various materials. One major application of centrifugal spinning is to produce advanced functional nanofibers for energy storage. Among the various existing energy storage technologies, rechargeable lithium-ion batteries have been considered as effective solution to the increasing need for highenergy density electrochemical power sources. Novel centrifugally-spun nanofibers with functional properties can dramatically alter surface reaction rates and charge transport throughout the batteries, causing significant improvement in energy storage efficiency. Here, we present our work on the development of advanced functional nanofibers and the integration of these materials into rechargeable lithium-ion batteries to achieve high system performance.
The main aim of this research is the production of different biopolymeric fibers by electrospinning and the determination of the optimum working parameters for each polymer analyzed. In particular, three different bio...
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