The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform
Yang Yang - One of the best experts on this subject based on the ideXlab platform.
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Nanocellulose Stabilized Pickering Emulsion Templating for Thermosetting AESO Nanocomposite Foams.
Polymers, 2018Co-Authors: Guo Mengya, Yang YangAbstract:Emulsion templating has emerged as an effective approach to prepare polymer-based Foams. This study reports a thermosetting Nanocomposite Foam prepared by nanocellulose stabilized Pickering emulsion templating. The Pickering emulsion used as templates for the polymeric Foams production was obtained by mechanically mixing cellulose nanocrystals (CNCs) water suspensions with the selected oil mixtures comprised of acrylated epoxidized soybean oil (AESO), 3-aminopropyltriethoxysilane (APTS), and benzoyl peroxide (BPO). The effects of the oil to water weight ratio (1:1 to 1:3) and the concentration of CNCs (1.0⁻3.0 wt %) on the stability of the emulsion were studied. Emulsions were characterized according to the emulsion stability index, droplet size, and droplet distribution. The emulsion prepared under the condition of oil to water ratio 1:1 and concentration of CNCs at 2.0 wt % showed good stability during the two-week storage period. Nanocomposite Foams were formed by heating the Pickering emulsion at 90 °C for 60 min. Scanning electron microscopy (SEM) images show that the Foam has a microporous structure with a non-uniform cell size that varied from 0.3 to 380 μm. The CNCs stabilized Pickering emulsion provides a versatile approach to prepare innovative functional bio-based materials.
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Nanocellulose Stabilized Pickering Emulsion Templating for Thermosetting AESO Nanocomposite Foams
MDPI AG, 2018Co-Authors: Mengya Guo, Yang YangAbstract:Emulsion templating has emerged as an effective approach to prepare polymer-based Foams. This study reports a thermosetting Nanocomposite Foam prepared by nanocellulose stabilized Pickering emulsion templating. The Pickering emulsion used as templates for the polymeric Foams production was obtained by mechanically mixing cellulose nanocrystals (CNCs) water suspensions with the selected oil mixtures comprised of acrylated epoxidized soybean oil (AESO), 3-aminopropyltriethoxysilane (APTS), and benzoyl peroxide (BPO). The effects of the oil to water weight ratio (1:1 to 1:3) and the concentration of CNCs (1.0–3.0 wt %) on the stability of the emulsion were studied. Emulsions were characterized according to the emulsion stability index, droplet size, and droplet distribution. The emulsion prepared under the condition of oil to water ratio 1:1 and concentration of CNCs at 2.0 wt % showed good stability during the two-week storage period. Nanocomposite Foams were formed by heating the Pickering emulsion at 90 °C for 60 min. Scanning electron microscopy (SEM) images show that the Foam has a microporous structure with a non-uniform cell size that varied from 0.3 to 380 μm. The CNCs stabilized Pickering emulsion provides a versatile approach to prepare innovative functional bio-based materials
Zhenning Liu - One of the best experts on this subject based on the ideXlab platform.
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a self standing Nanocomposite Foam of polyaniline reduced graphene oxide for flexible super capacitors
Synthetic Metals, 2015Co-Authors: Hang Sun, Ping She, Yinxing Shang, Shengyan Yin, Zhenning LiuAbstract:Abstract Self-standing three-dimensional Nanocomposite Foam of polyaniline (PANI) and reduced graphene oxide (rGO) has been fabricated by a convenient template-directed preparation of rGO and subsequent in situ polymerization of aniline on pre-formed rGO Foam, which can be directly used as electrodes for flexible supercapacitors. The Nanocomposite Foam of PANI@rGO possesses the advantages of self-standing, Foam-like high porosity, low density (∼8.3 mg cm −3 ), good flexibility and improved durability, which collaboratively lead to superior electrochemical performance, as a result of enhanced charge-transfer and mechanical support afforded by the rGO skeleton. The Nanocomposite-based supercapacitor not only displays a high specific capacitance of 701 F g −1 at the current density of 1 A g −1 , but also demonstrates improved cycling stability, retaining 92% of its starting capacitance after 1000 charge–discharge cycles. Moreover, the bended symmetric pseudocapacitor based on the flexible Nanocomposite Foam of PANI@rGO exhibits a high specific capacitance of 285 F g −1 at 1 A g −1 , indicating excellent potential for real energy storage in flexible supercapacitors. The approach presented here shows great promise for the development of flexible low-density electrode materials with good potential for applications in portable electronic devices.
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A self-standing Nanocomposite Foam of polyaniline@reduced graphene oxide for flexible super-capacitors
Synthetic Metals, 2015Co-Authors: Hang Sun, Ping She, Yinxing Shang, Shengyan Yin, Zhenning LiuAbstract:Abstract Self-standing three-dimensional Nanocomposite Foam of polyaniline (PANI) and reduced graphene oxide (rGO) has been fabricated by a convenient template-directed preparation of rGO and subsequent in situ polymerization of aniline on pre-formed rGO Foam, which can be directly used as electrodes for flexible supercapacitors. The Nanocomposite Foam of PANI@rGO possesses the advantages of self-standing, Foam-like high porosity, low density (∼8.3 mg cm −3 ), good flexibility and improved durability, which collaboratively lead to superior electrochemical performance, as a result of enhanced charge-transfer and mechanical support afforded by the rGO skeleton. The Nanocomposite-based supercapacitor not only displays a high specific capacitance of 701 F g −1 at the current density of 1 A g −1 , but also demonstrates improved cycling stability, retaining 92% of its starting capacitance after 1000 charge–discharge cycles. Moreover, the bended symmetric pseudocapacitor based on the flexible Nanocomposite Foam of PANI@rGO exhibits a high specific capacitance of 285 F g −1 at 1 A g −1 , indicating excellent potential for real energy storage in flexible supercapacitors. The approach presented here shows great promise for the development of flexible low-density electrode materials with good potential for applications in portable electronic devices.
Chul B Park - One of the best experts on this subject based on the ideXlab platform.
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microcellular injection molded outstanding oleophilic and sound insulating pp ptfe Nanocomposite Foam
Composites Part B-engineering, 2021Co-Authors: Guilong Wang, Jinchuan Zhao, Zuolong Chen, Yifeng Huang, Chongda Wang, Aimin Zhang, Chul B ParkAbstract:Abstract Lightweight and open-cell thermoplastic Foams have proven superior to common counterparts in terms of functional performances, such as oil absorption, sound and thermal insulation, contributing to energy saving, environmental protection, and sustainable development of the economy and society. Herein, a novel strategy was employed to prepare lightweight, oleophilic, and sound-insulating polypropylene (PP)/polytetrafluoroethylene (PTFE) composite Foams by combining the microcellular injection molding (MIM) and in-situ fibrillation technologies. Thanks to the pronouncedly promoted crystallization and melt strength of the PP matrix by the nano-fibrillar PTFE fibrils obtained by the in-situ fibrillation process, the Foaming ability of PP in the MIM process was effectively improved, reaching an expansion ratio of up to 20.2 and a cell population density of 108 cells/cm3. Notably, the nano-scale structures on cell walls together with thin cell-wall thickness of the PP/PTFE Foam, significantly increased the open-cell content to 98.3%. The high porosities and large expansion ratios, assisted by the capillary penetration action caused by the uniquely elongated cells, effectively increased the oil absorption capacity up to 22.5 g/g with a high recovery of 97.4%, particularly for raw crude oil. Moreover, a high porosity and low airflow resistivity dramatically improved the sound insulation by reducing impedance and enhancing viscous dissipation, presenting as a sound absorption coefficient of higher than 0.5, and a transmission loss of up to 50 dB. Hence, the flexible, scalable and cost-effective MIM technology shows a promising future in the manufacture of multifunctional microcellular polymer products.
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lightweight and strong microcellular injection molded pp talc Nanocomposite
Composites Science and Technology, 2018Co-Authors: Guilong Wang, Guoqun Zhao, Guiwei Dong, Chul B ParkAbstract:Abstract Lightweight is of great significance for reducing material and energy consumptions. Microcellular injection molding is an advanced technology for fabricating lightweight plastic structural components, but the deteriorated mechanical performance is a big challenge. In this study, we reported a facile and scalable way to fabricate the lightweight and strong microcellular polypropylene/talcum (PP/talc) component. Both PP/talc microcomposite and PP/talc Nanocomposite were prepared by the twin-screw compounding, and the SEM images show a uniform dispersion of talc. The DSC analysis results demonstrate that either the micro or nano talc is very effective in promoting the crystallization of PP. The rheological tests show that both the micro talc and the nano talc lead to obviously enhanced viscoelastic properties of the PP melt, while the effect of the nano talc is much more pronounced than that of the micro talc. Thanks to the enhanced crystallization and improved viscoelastic behavior, both the microcomposite Foam and the Nanocomposite Foam shows much refined cellular structure than the pure PP Foam. The PP/talc microcomposite Foam shows significantly improved strength but seriously deteriorated toughness, compared with the pure PP Foam. In contrast, the PP/talc Nanocomposite Foam shows simultaneously improved strength, rigidity and toughness. Notably, the tensile toughness and the Gardner impact toughness of the PP/talc Nanocomposite Foam are dramatically enhanced by 226.1% and 166.2%, respectively. Taking into account the flexible and scalable features of the processing methodology, the lightweight and strong PP/talc Nanocomposite Foam shows a promising future to replace the solid structural components in many industrial applications such as automotive and consumer electronics.
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Advanced bimodal polystyrene/multi-walled carbon nanotube Nanocomposite Foams for thermal insulation
Carbon, 2017Co-Authors: Pengjian Gong, Guilong Wang, Minh-phuong Tran, Piyapong Buahom, Shuo Zhai, Chul B ParkAbstract:Abstract We developed an advanced bimodal polystyrene (PS)/multi-walled carbon nanotube (MWCNT) Nanocomposite Foam with a very low thermal conductivity of 30 mW/m-K without using any insulation gas. The MWCNTs significantly decreased the radiative thermal conductivity of the Foams with the high infrared (IR) absorption capability and increased the optimal expansion ratio of the Foams to minimize the total thermal conductivity. The radiative blocking effect of MWCNTs was quantitatively modeled by calculating the IR absorption index of the unFoamed Nanocomposites and calculating the IR extinction coefficient of the Foamed Nanocomposites. In addition, a theoretical model to analyze the optimal expansion ratio in synergistic bimodal Nanocomposite Foam was developed for the first time. The calculated values were in good agreement with the experimental data to verify the superior heat-blocking characteristics of the MWCNTs in the bimodal cellular morphology.
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Towards the development of uniform closed cell Nanocomposite Foams using natural rubber containing pristine and organo-modified nanoclays
RSC Advances, 2016Co-Authors: Ali Vahidifar, Chul B Park, Saied Nouri Khorasani, Hossein Ali Khonakdar, Uta Reuter, Hani E. Naguib, Elnaz EsmizadehAbstract:A closed cell rubber Foam, based on a natural rubber (NR)/nanoclay Nanocomposite, was produced using a one-step Foaming process with compression molding. The effects of three different nanoclays on the properties of the NR/nanoclay Nanocomposite Foam were examined: an un-modified nanoclay (Cloisite Na+) and two organo-modified nanoclays (Cloisite 20A and Cloisite 30B). We examined their curing behavior, Foam morphology, sound absorption, and their mechanical and thermal properties. The morphological results from X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) showed that the Cloisite Na+ agglomerated in the NR matrix while an intercalated-exfoliated/fully-exfoliated morphology was seen in the Cloisite 30B and the Cloisite 20A, respectively. The rheometry results showed that all three nanoclay types increased the NR's curing rate, and also accelerated its scorch and curing time. Other results showed that the organo-modified nanoclays, which were the ammonium-salt modified nanoclays (Cloisite 30B and Cloisite 20A), improved the Foam's curing behavior more than the pristine Cloisite Na+. Using the one-step Foaming process kept the Nanocomposite Foam density and expansion ratio constant in all of the samples, independent of the nanoclay type. Meanwhile, the scanning electron microscopy (SEM) results showed that the nanoclay increased the cell density and decreased the cell size, depending on the nanoclay type. The mechanical properties of NR Nanocomposite Foams including the hardness and the modulus were improved by incorporating the nanoclays. At the same time, there was a gradual deterioration in the Foams' sound absorption and thermal stability behavior.
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Nanofiber fluorescence coating for evaluation of complex solid-/gas-multi-phase and nano-/micro- multi-scale Nanocomposite Foam structure
Progress in Organic Coatings, 1Co-Authors: Pengjian Gong, Chul B Park, Yunjiao Qiao, Yajiang Huang, Hong JiangAbstract:Abstract Dual fluorescence design based on chemical coating and physical staining was successfully applied in revealing the multi-phase and multi-scale structure simultaneously in Nanocomposite Foams for the first time (that is nanometer-scale solid phase fillers selectively located chemical coating fluorescence, micrometer-scale solid phase cell walls selectively located physical staining fluorescence and air phase bubbles selectively located no fluorescence). The hybrid fluorescence modification method enables us to selectively locate different fluorescence dyes on nanofiber surface and in polymer matrix. Furthermore, quantitative analysis of the three-dimensional (3D) nanofiber network structure in Nanocomposite Foams is studied in-depth via numerical reconstruction. The evolution of 3D nanofiller network structure in multi-phase and multi-scale Nanocomposite Foams is demonstrated via both experimental visualization and numerical calculation. It is found that the average shortest nanofiber distance decreases with increasing cell wall thickness and with decreasing air content. Therefore, the dual fluorescence design exploring 3D functional filler network structure in complicated multi-phase and multi-scale Nanocomposite Foams greatly helps researchers study the structure-performance relationship of multi-functional materials with nanoscale functional fillers.
Yuyang Qin - One of the best experts on this subject based on the ideXlab platform.
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lightweight mechanically flexible and thermally superinsulating rgo polyimide Nanocomposite Foam with an anisotropic microstructure
Nanoscale Advances, 2019Co-Authors: Yuyang Qin, Qingyu Peng, Xu Zhao, Yue Zhu, Zaishan LinAbstract:We report that lightweight, anisotropic, mechanically flexible, and high performance thermally insulating materials are fabricated by the assembly of graphene oxide (GO) and polyimide (PI). With an appropriate ratio between GO and PI building blocks, the rGO/PI thermally insulating material exhibits hierarchically aligned microstructures with high porosity. These microstructures endow the rGO/PI Nanocomposite with low mass density and super-insulating property (extremely low thermal conductivity of 0.012 W m−1 K−1 in the radial direction). Meanwhile, the introduction of PI enhances the mechanical strength and thermal stability of rGO Foam. Our rGO/PI Nanocomposites as super-insulating Foams with a low thermal conductivity are highly attractive for potential thermal insulation applications in aerospace, wearable devices, and energy-efficient buildings.
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Superlight, Mechanically Flexible, Thermally Superinsulating, and Antifrosting Anisotropic Nanocomposite Foam Based on Hierarchical Graphene Oxide Assembly
ACS Applied Materials and Interfaces, 2017Co-Authors: Qingyu Peng, Yuyang Qin, Zaishan Lin, Xianxian Sun, Fan Xu, Ying Li, Xu Zhao, Ye Yuan, Qiang Chen, Jianjun LiAbstract:Lightweight, high-performance, thermally insulating, and antifrosting porous materials are in increasing demand to improve energy efficiency in many fields, such as aerospace and wearable devices. However, traditional thermally insulating materials (porous ceramics, polymer-based sponges) could not simultaneously meet these demands. Here, we propose a hierarchical assembly strategy for producing Nanocomposite Foams with lightweight, mechanically flexible, superinsulating, and antifrosting properties. The Nanocomposite Foams consist of a highly anisotropic reduced graphene oxide/polyimide (abbreviated as rGO/PI) network and hollow graphene oxide microspheres. The hierarchical Nanocomposite Foams are ultralight (density of 9.2 mg·cm–3) and exhibit ultralow thermal conductivity of 9 mW·m–1·K–1, which is about a third that of traditional polymer-based insulating materials. Meanwhile, the Nanocomposite Foams show excellent icephobic performance. Our results show that hierarchical Nanocomposite Foams have promi...
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lightweight superelastic and mechanically flexible graphene polyimide Nanocomposite Foam for strain sensor application
ACS Nano, 2015Co-Authors: Yuyang Qin, Zaishan Lin, Qingyu Peng, Yujie Ding, Chunhui Wang, Ye YuanAbstract:The creation of superelastic, flexible three-dimensional (3D) graphene-based architectures is still a great challenge due to structure collapse or significant plastic deformation. Herein, we report a facile approach of transforming the mechanically fragile reduced graphene oxide (rGO) aerogel into superflexible 3D architectures by introducing water-soluble polyimide (PI). The rGO/PI Nanocomposites are fabricated using strategies of freeze casting and thermal annealing. The resulting monoliths exhibit low density, excellent flexibility, superelasticity with high recovery rate, and extraordinary reversible compressibility. The synergistic effect between rGO and PI endows the elastomer with desirable electrical conductivity, remarkable compression sensitivity, and excellent durable stability. The rGO/PI Nanocomposites show potential applications in multifunctional strain sensors under the deformations of compression, bending, stretching, and torsion.
Guo Mengya - One of the best experts on this subject based on the ideXlab platform.
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Nanocellulose Stabilized Pickering Emulsion Templating for Thermosetting AESO Nanocomposite Foams.
Polymers, 2018Co-Authors: Guo Mengya, Yang YangAbstract:Emulsion templating has emerged as an effective approach to prepare polymer-based Foams. This study reports a thermosetting Nanocomposite Foam prepared by nanocellulose stabilized Pickering emulsion templating. The Pickering emulsion used as templates for the polymeric Foams production was obtained by mechanically mixing cellulose nanocrystals (CNCs) water suspensions with the selected oil mixtures comprised of acrylated epoxidized soybean oil (AESO), 3-aminopropyltriethoxysilane (APTS), and benzoyl peroxide (BPO). The effects of the oil to water weight ratio (1:1 to 1:3) and the concentration of CNCs (1.0⁻3.0 wt %) on the stability of the emulsion were studied. Emulsions were characterized according to the emulsion stability index, droplet size, and droplet distribution. The emulsion prepared under the condition of oil to water ratio 1:1 and concentration of CNCs at 2.0 wt % showed good stability during the two-week storage period. Nanocomposite Foams were formed by heating the Pickering emulsion at 90 °C for 60 min. Scanning electron microscopy (SEM) images show that the Foam has a microporous structure with a non-uniform cell size that varied from 0.3 to 380 μm. The CNCs stabilized Pickering emulsion provides a versatile approach to prepare innovative functional bio-based materials.
