• Title/Summary/Keyword: polymer nanocomposites

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Influence of Processing on Morphology, Electrical Conductivity and Flexural Properties of Exfoliated Graphite Nanoplatelets-Polyamide Nanocomposites

  • Liu, Wanjun;Do, In-Hwan;Fukushima, Hiroyuki;Drzal, Lawrence T.
    • Carbon letters
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    • v.11 no.4
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    • pp.279-284
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    • 2010
  • Graphene is one of the most promising materials for many applications. It can be used in a variety of applications not only as a reinforcement material for polymer to obtain a combination of desirable mechanical, electrical, thermal, and barrier properties in the resulting nanocomposite but also as a component in energy storage, fuel cells, solar cells, sensors, and batteries. Recent research at Michigan State University has shown that it is possible to exfoliate natural graphite into graphite nanoplatelets composed entirely of stacks of graphene. The size of the platelets can be controlled from less than 10 nm in thickness and diameters of any size from sub-micron to 15 microns or greater. In this study we have investigated the influence of melt compounding processing on the physical properties of a polyamide 6 (PA6) nanocomposite reinforced with exfoliated graphite nanoplatelets (xGnP). The morphology, electrical conductivity, and mechanical properties of xGnP-PA6 nanocomposite were characterized with electrical microscopy, X-ray diffraction, AC impedance, and mechanical properties. It was found that counter rotation (CNR) twins crew processed xGnP/PA6 nanocomposite had similar mechanical properties with co-rotation (CoR) twin screw processed or with CoR conducted with a screw design modified for nanoparticles (MCoR). Microscopy showed that the CNR processed nanocomposite had better xGnP dispersion than the (CoR) twin screw processed and modified screw (MCoR) processed ones. It was also found that the CNR processed nanocomposite at a given xGnP content showed the lowest graphite X-ray diffraction peak at $26.5^{\circ}$ indicating better xGnP dispersion in the nanocomposite. In addition, it was also found that the electrical conductivity of the CNR processed 12 wt.% xGnP-PA6 nanocomposite is more than ten times higher than the CoR and MCoR processed ones. These results indicate that better dispersion of an xGnP-PA6 nanocomposite is attainable in CNR twins crew processing than conventional CoR processing.

Synthesis of NiO-CuO Nano Composite using Nickel(II) Nitrate Metal Salt as a Precursor (금속질산염을 전구체로 사용한 NiO-CuO 나노복합재료의 합성)

  • Soo-Jong Kim;Jae-Ho Kim
    • The Journal of the Convergence on Culture Technology
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    • v.10 no.6
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    • pp.671-676
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    • 2024
  • Ceramic nanocomposites made of two metal oxides exhibiting different properties exhibit better improved properties than the electrical, optical, magnetic, and catalytic properties of their single oxides. These Ceramics nanoparticles have remarkably different properties of the particles produced depending on how they are synthesized. This study aims to synthesize NiO-CuO nanocomposites using a new synthesis method and to investigate the properties of the resulting NiO-CuO particles. NiO-CuO nanocomposite nanoparticles were synthesized using an aqueous solution prepared from nickel and copper nitrates as a precursor. It was confirmed that a NiO-CuO noncomposite was formed even when the precursor impregnated with starch, a natural polymer matrix, in which the aqueous metal salt solution of nickel and copper was calcined at a low temperature. In addition, the crystal structure, constituent elements, and particle size of NiO-CuO particles generated as the calcination temperature of the precursor increased were analyzed by X-ray diffraction analysis (XRD), EDS, and SEM. It is confirmed that a pure NiO-CuO phase was formed at the calcination temperature of 400℃, and the particle size and crystallinity of the produced NiO-CuO composite material increased as the calcination temperature increased.

Synthesis of polystyrene-clay nanocomposites and investigation of their barrier property (폴리스티렌-클레이 나노 복합재료의 합성 및 차단 특성에 관한 연구)

  • Dhungana, Biraj;Son, Younggon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.5
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    • pp.2544-2549
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    • 2013
  • In prepaparation of the high performance polymer/clay nanocomposite, it is essential to modify the hydrophillic $Na^+$-MMT to hydrophobic alkyl ammonium-MMT via organic surfactant. The organic surfactant, VDAC (vinylbenzyldimethyl-dodecylammonium chloride) was synthesized from two primary chemicals and $VDA^+$-MMT was prepared from $Na^+$-MMT through a cation exchange reaction between $Na^+$ and $VDA^+$ (vinylbenzyldimethyl-$dodecylammonium^+$) cation. $VDA^+$-MMT was then dispersed in styrene and polystyrene/$VDA^+$-MMT nanocomposite was fabricated by in-situ polymerization reaction. The clay dispersion and barrier property of the nanocomposite were investigated. From the investigations, it was confirmed that dispersion of the $VDA^+$-MMT was enhanced compared with that of $Na^+$-MMT and as a consequency of better dispersion, barrier property of organic solvent was improved in a great extent.

Study on the Thermomechanical Properties of Epoxy-Silica Nanocomposites by FTIR Molecular Structure Analyses (FTIR 분자구조 해석을 통한 에폭시-실리카 나노복합소재의 열기계적 물성 연구)

  • Jang, SeoHyun;Han, Yusu;Hwang, DoSoon;Jung, Juwon;Kim, YeongKook
    • Journal of the Microelectronics and Packaging Society
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    • v.28 no.2
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    • pp.51-57
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    • 2021
  • This paper analyzed the effects of the concentration of nano-silica particles contained in epoxy resin on the thermomechanical properties of the composite materials. The 12nm sized nanoparticles were mixed with epoxy polymer by 5 different weight ratios for the test samples. The glass transition temperature, stress relaxation, and thermal expansion behaviors were measured using dymanic mechanical analyzer (DMA) and thermomechanical analyzer (TMA). It was shown that the nano particle mixing ratios had significant influences on the viscoelastic behaviors of the materials. As the content of the silica particles was increased, the elastic modulus was also increased, while the glass transition temperatures were decreased. Fourier Transform Infrared Spectroscopy (FTIR) results played an important role in determining the causes of the property changes by the filler contents in terms of the molecular structures, enabling the interpretations on the material behaviors based on the chemical structure changes.

Analyses of Nano Epoxy-Silica Degradation in LEO Space Environment (저궤도 우주환경에서 에폭시-실리카 나노 복합소재의 열화거동 분석)

  • Jang, Seo-Hyun;Han, Yusu;Hwang, Do Soon;Jung, Joo Won;Kim, Yeong Kook
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.48 no.12
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    • pp.945-952
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    • 2020
  • In this study, the effects of Low Earth Orbit(LEO) environments on the degradation behavior of epoxy nano silica composite materials were investigated. The nanocomposite materials containing silica particles in different weight ratios of 10% and 18% were prepared and degraded in a LEO simulator to compare with the neat epoxy cases. Thermogravimetric analysis (TGA) was performed on the degraded nanocomposites and the activation energies were calculated by Friedman method, Flynn-Wall-Ozawa (FWO) method, Kissinger method, and DAEM (Distributed Activation Energy Method) based on the iso-conversional method. As the results, for the neat epoxy sample cases, it was found that the average activation energy was increased as the degradation was progressed. When the nano particles were mixed, however, the energy increased to the 15 environmental test cycles, and decreased afterwards, meaning that the particle mixture contributed adversely to the thermal degradation. Discussions on the results of the different calculation methods were also given.

Flexible Energy Harvesting Device based on Hybrid Piezoelectric Nanocomposite made of Lead-Free BCTZ Ceramic and Piezo-polymer (비납계 BCTZ 압전세라믹과 압전폴리머로 제작된 하이브리드 나노복합체 기반의 플렉서블 에너지 하베스팅 소자)

  • Park, Sung Cheol;Lee, Jae Hoon;Kim, Yeon-gyu;Park, Kwi-Il
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.35 no.1
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    • pp.72-79
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    • 2022
  • Piezoelectric energy harvesting technologies, which can be used to convert the electricity from the mechanical energy, have been developed in order to assist or power the wearable electronics. To realize non-toxic and biocompatible electronics, the lead-free (Ba0.85Ca0.15)(Ti0.90Zr0.10)O3 (BCTZ) nanoparticles (NPs) are being studied with a great attention as flexible energy harvesting device. Herein, piezoelectric hybrid nanocomposites were fabricated using BCTZ NPs-embedded poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] matrix to improve the performance of flexible energy harvester. Output performance of the fabricated energy device was investigated by the well-optimized measurement system during the periodically bending and releasing motions. The generated open-circuit voltage and the short-circuit current of the piezoelectric hybrid nanocomposite-based energy harvester reached up to ~15 V and ~1.1 ㎂, respectively; moreover, the instantaneous power of 3.5 ㎼ is determined from load voltage and current at the external load of 20 MΩ. This research is expected to cultivate a new approach to high-performance wearable self-powering electronics.

Increasing the attractiveness of physical education training with the involvement of nanotechnology

  • Jinyan Ge;Yuxin Hong;Rongtian Zeng;Yunbin Li;Mostafa Habibi
    • Advances in concrete construction
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    • v.16 no.6
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    • pp.291-302
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    • 2023
  • As the first part of the body that strikes the ground during running, sports shoes are especially important for improving performance and reducing injuries. The use of new nanotechnology materials in the shoe's sole that can affect the movement angle of the foot and the ground reaction forces during running has not been reported yet. It is important to consider the material of the sole of the shoe since it determines the long-term performance of sports shoes, including their comfort while walking, running, and jumping. Running performance can be improved by polymer foam that provides good support with low energy dissipation (low energy dissipation). Running shoes have a midsole made of ethylene propylene copolymer (EPP) foam. The mechanical properties of EPP foam are, however, low. To improve the mechanical performance of EPP, conventional mineral fillers are commonly used, but these fillers sacrifice energy return. In this study, to improve the magnificence of physical education training with nanotechnology, carbon nanotubes (CNTs) derived from recycled plastics were prepared by catalytic chemical vapor deposition and used as nucleating and reinforcing agents. As a result of the results, the physical, mechanical, and dynamic response properties of EPP foam combined with CNT and zinc oxide nanoparticles were significantly improved. When CNT was added to the nanocomposites with a weight percentage of less than 0.5 wt%, the wear resistance, physical properties, dynamic stiffness, compressive strength, and rebound properties of EPP foams were significantly improved.

Fire-Protective Coating for Polymer Construction Materials using Two-dimensional Nanomaterials (2차원 나노소재를 활용한 고분자 건축자재의 난연코팅기술 개발)

  • Kim, Hanim
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.44 no.2
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    • pp.183-190
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    • 2024
  • An environmentally-friendly nanocoating method that effectively adds flame retardant(FR) and gas shielding properties to combustible polymeric construction materials such as flexible polyurethane (PU) foam was studied. Naturally-driven two-dimensional(2D) nanomaterials such as graphene oxide (GO) can exhibit liquid crystalline (LC) properties in aqueous solutions, enabling uniform coatings on the various substrates including 3D-porous foams. LC phase-assisted coating serves as 3D-scaffold, facilitating the introduction of small molecules having antioxidant capabilities such as dopamine which is to form uniformly stacked FR coating. Additionally, the structural characteristics of the 2D-materials can effectively hinder the migration of toxic gases and flammable substances in the gas phase generated during combustion. This LC phase flame retardant coating technology could be a new approach to provide environmentally friendly and effective flame retardant and gas barrier properties to various types of polymeric materials.

Modification of Silica Nanoparticles with Bis[3-(triethoxysilylpropyl)]tetrasulfide and Their Application for SBR Nanocomposite (Bis[3-(triethoxysilylpropyl)]tetrasulfide에 의한 실리카 입자의 표면개질 반응과 SBR 나노 복합체 응용)

  • Ryu, Hyun Soo;Lee, Young Seok;Lee, Jong Cheol;Ha, KiRyong
    • Polymer(Korea)
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    • v.37 no.3
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    • pp.308-315
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    • 2013
  • In this study, we performed surface modification of silica nanoparticles with bis[3-(triethoxysilylpropyl)]tetrasulfide (TESPT) silane coupling agent to study the effects of treatment temperature, treatment time, and amount of TESPT used on the silanization degree with Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), elemental analysis (EA) and solid state $^{13}C$ and $^{29}Si$ cross-polarization magic angle spinning (CP/MAS) nuclear magnetic resonance spectroscopy (NMR). We found peak area of isolated silanol groups at $3747cm^{-1}$ decreased, but peak area of $-CH_2$ asymmetric stretching of TESPT at $2938cm^{-1}$ increased with the amount of TESPT from FTIR measurements. We also used universal testing machine (UTM) to study mechanical properties of styrene butadiene rubber (SBR) nanocomposites with 20 phr (parts per hundred of rubber) of pristine and TESPT modified silicas, respectively. The tensile strength and 100% modulus of modified silica/SBR nanocomposite were enhanced from 5.65 to 9.38MPa, from 1.62 to 2.73 MPa, respectively, compared to those of pristine silica/SBR nanocomposite.

Silica/polymer Nanocomposite Containing High Silica Nanoparticle Content : Change in Proton Conduction and Water Swelling with Surface Property of Silica Nanoparticles (고농도의 Silica Nanoparticle을 함유한 Silica/polymer 나노복합체 : 실리카 표면 특성에 따른 수소이온 전도성 및 수팽윤도 변화)

  • Kim, Ju-Young;Kim, Seung-Jin;Na, Jae-Sik
    • Applied Chemistry for Engineering
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    • v.21 no.5
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    • pp.514-521
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    • 2010
  • A new one-shot process was employed to fabricate proton exchange membranes (PEMs) over conventional solvent-casting process. Here, PEMs containing nano-dispersed silica nanoparticles were fabricated using one-shot process similar to the bulk-molding compounds (BMC). Different components such as reactive dispersant, urethane acrylate nonionmer (UAN), styrene, styrene sulfuric acid and silica nano particles were dissolved in a single solvent dimethyl sulfoxide (DMSO) followed by copolymerization within a mold in the presence of radical initiator. We have successfully studied the water-swelling and proton conductivity of obtained nanocomposite membranes which are strongly depended on the surface property of dispersed silica nano particles. In case of dispersion of hydrophilic silica nanoparticles, the nanocomposite membranes exhibited an increase in water-swelling and a decrease in methanol permeability with almost unchanged proton conductivity compared to neat polymeric membrane. The reverse observations were achieved for hydrophobic silica nanoparticles. Hence, hydrophilic and hydrophobic silica nanoparticles were effectively dispersed in hydrophilic and hydrophobic medium respectively. Hydrophobic silica nanoparticles dispersed in hydrophobic domains of PEMs largely suppressed swelling of hydrophilic domains by absorbing water without interrupting proton conduction occurred in hydrophilic membrane. Consequently, proton conductivity and water-swelling could be freely controlled by simply dispersing silica nanopartilces within the membrane.