• Journal of the Korean Applied Science and Technology
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• v.40 no.4
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• pp.913-923
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• 2023

In this study, a triboelectric nanogenerator was fabricated using the composite of teflon-based polymer and graphene flower, which are stable in air and have relatively high electronegativity. The composite was used to fabricate an electronegative layer of a nanogenerator using a spin-coating method. For the electropositive layer, a zinc oxide film was prepared using a sol-gel method. The fabricated triboelectric nanogenerator produced a maximum power of about 44 ㎼. In conclusion, since all the active layers of the triboelectric nanogenerator was made by the solution process, it is scalable to a large area.

• Air Cleaning Technology
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• v.33 no.2
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• pp.1-9
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• 2020

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.383-383
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• 2012

최근 나노 소재의 활용 가능성이 확대되어감에 따라 다양한 소재의 나노구조체에 대한 연구가 진행되어 왔다. 그 중 은(Silver)은 열전도율과 전기전도율이 가장 우수한 금속으로 다양한 형태의 은 나노 입자를 형성할 수 있고. 이를 탄소, 비석, 고분자 등의 기판에 다양한 방법으로 성장시키는 연구가 진행되었다. 기판으로 사용되는 재료 중 탄소 복합소재는 내열성, 화학적 안정성, 열전도성, 저열팽창성에 따른 치수 안정성, 유연성 등의 우수한 특징을 지니고 있으며 최근까지 방열 소재로서 활용되고 있다. 본 연구에서는 탄소섬유의 표면에 다양한 결정 구조를 가지는 Ag seed 입자를 형성하고 폴리올 공정을 통하여 와이어 형태의 나노구조체를 성장시켜 그 형상제어 특성을 FE-SEM을 통하여 확인하였다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.155.1-155.1
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• 2007

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3627-3632
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• 2015

We investigated mechanical, rheological and electrical properties of graphite/PP/LCP composites for a bipolar plate of the polymer electrolyte membrane fuel cell. The composites containing very low molecular weighted PP showed much higher electrical conductivity compared with other thermoplastics. This was attributed to the enhanced dispersion of graphite particles due to the low viscosity of the PP. The conductivity of the composites was increased in a great extent by incorporation of small amount of carbon nano tube (CNT). However, the acid treated CNT which contains oxygen atoms did not increase the conductivity of the composite. From this result, it is concluded that the CNT has higher affinity with non polar polymer. The composite with low molecular weighted PP provided good processability so that the composites can be processed by an injection molding while the mechanical strength is deficient compared to other polymers. In order to reinforce the low mechanical property, LCP/PP was used as a binder and the graphite/PP/LCP composite showed the higher conductivity and moderate mechanical strength maintaining suitable processability.

• Composites Research
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• v.30 no.5
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• pp.316-322
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• 2017

Carbon fiber is a material with excellent mechanical, electrical and thermal properties, which is widely used as a composite material made of a polymer matrix. However, this composite material has a weak point of interlaminar delamination due to weak interfacial bond with polymer matrix compared with high strength and elasticity of carbon fiber. In order to solve this problem, it is essential to use reinforcements. Due to excellent mechanical properties, graphene have been expected to have large improvement in physical properties as a reinforcing material. However, the aggregation of graphene and the weak interfacial bonding have resulted in failure to properly implement reinforcement effect. In order to solve this problems, dispersibility will be improved. In this study, functionalization of graphene nanoplatelet was proceeded with melamine and mixed with epoxy polymer matrix. The carbon fiber reinforced polymer composites were fabricated using the prepared graphene nanoplatelet/epoxy and flexural properties and interlaminar shear strength were measured. As a result, it was confirmed that the dispersibility of graphene nanoplatelet was improved and the mechanical properties of the composite material were increased.

• Composites Research
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• v.32 no.6
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• pp.342-348
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• 2019

Development of flame retarding polymer based materials has been studied actively due to the increase in use of polymers. The post treatment of manufactured fibers or the introduction of flame retardant into fibers is representative method for the way to improve the flame retardancy. Among the polymers, polyacrylonitrile (PAN), which is a precursor of carbon fiber, has been widely used for clothes. Due to low flame retardancy of PAN fiber (LOI value: 17~18%), the improvement of flame retardancy of PAN fiber is needed. In this review paper, we report preparation methods for the fabrication of post-treated (oxidization or chemical reaction) flame-retarding PAN fibers and composites composed of PAN and organic/inorganic materials (SiO₂, 2D materials or CNT).

• Composites Research
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• v.32 no.3
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• pp.127-133
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• 2019

Although carbon nanotubes(CNTs) have outstanding theoretical mechanical and electrical properties, CNT fibers(CNTFs) have not yet reached that level. Particularly, tensile strength is only about 10% or less, so studies for making up for it are being actively conducted. As a way for improving mechanical strength, methods such as synthesizing long CNT, orientation, chemical cross-linking, hydrogen bonding and polymer infiltration are being studied. In this review paper, we report preparation methods for highly conductive and strong CNTF/Carbon composites through coating and infiltration followed by carbonization of carbon precursor polymers such as polyacrylonitrile (PAN) and polydopamine (PDA) on CNTFs.

• Membrane Journal
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• v.27 no.2
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• pp.154-166
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• 2017

Polymeric films for gas barrier applications such as food packaging and electronic devices have attracted great interest due to their cheap, light and easy processability among gas barrier materials. Especially in electronic devices, extremely low gas permeance is necessary for maintaining the device performance. However, current polymeric barrier films still suffer from relatively high gas permeance than other materials. Therefore, there have been strong needs to enhance the gas barrier performance of polymeric barrier films while keep their own advantages. Recently, graphene is highlighted as a 2D-layered material for gas barrier applications. However, owing to the poor workability and difficulty to produce in engineering scale, graphene oxide (GO) is on the rise. GO consists of oxygen-containing functional groups on surface with intrinsic 2D-layered structure and high aspect ratio, and it can be well-dispersed in aqueous polar solvents like water, resulting in scalable mass production. Here, we prepared GO incorporated polyimide (PI) nanocomposites. PI is widely used barrier polymer with high mechanical strength and thermal and chemical stability. We demonstrated that PI/GO nanocomposites could perform as a gas barrier. Furthermore, surfactants (Triton X-100 (TX) and Sodium deoxycholate (SDC)) are introduced to enhance the gas barrier performance by improving the degree of dispersion of GO in PI matrix. As a result, TX enhanced the gas barrier performance of PI/GO nanocomposites which is similar to predicted value. This finding will provide new insight to polymer nanocomposites for gas barrier applications.

• Elastomers and Composites
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• v.45 no.3
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• pp.188-198
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• 2010

The term 'shape memory polymers (SMPs)' describes a class of polymers which can remember the original shape and recover from deformed to its original shape by the applied stimuli, e.g., heat, electricity, magnetic field, light, etc. SMPs are classified as one of the 'smart polymers' and have great potentials as high-value-added materials. Especially, low thermal, electrical, and mechanical properties of SMPs can be improved by incorporating the various fillers. This paper aims to review the SMPs and their basic principles, and the trends of the development of SMPs nanocomposites.