• Composites Research
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• v.32 no.6
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• pp.319-326
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• 2019

To address tremendous needs for developing efficiently heat dissipating material with lightweights, a new class of polymer possessing recyclable and malleable characteristics was synthesized for incorporating model functional hexagonal boron nitride (h-BN) filler. A good interfacial affinity between the polymer matrix and the filler along with shear force generated upon manufacturing the composite yielded the final product bearing highly aligned filler via simple hot pressing method. For this reason, the composite exhibited a high thermal conductivity of 13.8 W/mK. Moreover, it was possible to recover the h-BN from the composite without physical/chemical denaturation of the filler by chemically depolymerizing the matrix, thus the recovered filler can be re-used in the future. We believe this polymer could be beneficial as matrix for incorporating many other functional fillers, thus they may find applications in various polymeric composite related fields.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.7
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• pp.462-466
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• 2015

In this paper, we investigated the relations between dispersion of CNTs (carbon nanotubes) and electrical conductivity in the CNT/PVDF (polyvinylidene fluoride) composite film. By adding hydrophobic CNTs as filler into the PVDF matrix, we fabricated hydrophobic and electrically conducting polymer coating film. Dispersion of CNTs in the CNT/PVDF composite film plays a significant role in terms of electrical conductivity and wetting property. Spray coating method was used to form the CNT/PVDF composite films by injecting the dispersed CNTs in the PVDF solution with different weight ratios from 0.7 wt% to 7 wt%. We investigated the electrical properties and contact angles of the CNT/PVDF composite films with the CNT concentration. Finally we discussed the conducting mechanism and feasibility of the CNT/PVDF composite film for the conducting polymer films.

• Polymer(Korea)
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• v.26 no.1
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• pp.105-112
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• 2002

The low actuation voltage and quick bending response of IPMC(ion-exchange polymer metal composite) are considered attractive for the construction of various types of actuators. In this study, in order to develop a new type actuators by using the IPMC platinum electrode of IPMC are fabricated by using electroless impregnation-reduction method plating. As the platinum-plating times are increased, IPMC performance was improved in terms of bending displacement and force due to the enhanced surface conductivity. In addition, we investigated the basic actuation characteristics of resonance frequency and actuator length as well as the effect of water uptake and ion mobility. Using the classical laminate theory(CLT), a modeling methodology was developed to predict the deformation, bending moment, and residual stress distribution of anisotropic IPMC thin plates. In this modeling methodology, the internal stress evolved by the unsymmetric distribution of water inside IPMC was quantitatively calculated and subsequently the bending moment and the curvature were estimated for various geometry of IPMC actuator.

• Membrane Journal
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• v.6 no.4
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• pp.265-272
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• 1996

The (polymer/carrier) composite membranes for separating the metallic ion have been prepared by the water cast-method. The morphology of these membranes was affected by the physical properties of the spreading solution. The surface tension of the (polymer/18-crown-6) composite solution was decreased with increasing the concentration of 18-crown-6 compound and the surface tension of polymer solution decreased the following order PVC>PS>CA. The viscosity of CA solution decreased with increasing the contents of the 18-crown-6 compound, but PVC and PS solutions showed no significance changes according as the concentration of 18-crown-6 compound. In the composite solutions, the spreading ability was improved by' the cyclic 18-crown-6 molecules which acted as an electric buffer and diminished the intermolecular force between the polymer chains. The (polymer/18-crown-6) composite membrane was more uniform than that of the mono polymer membrane on the coagulation state of polymer, and the top and bottom sides of membrane showed also the more smooth structure according as the concentration increment of 18-crown-6 molecule.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.349-352
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• 1989

Poling piezoelectric ceramic-polymer composites with 0-3connectivity is difficult because of the high dielectric constant of most of the ferroelectric filler materials, and the high resistivity of the polymer matrix. To aid in poling this type of composite, conductivity of the polymer phase can be controlled by adding small amount of a semiconductor phase such as germanium, carbon or silicon. In this study, flexible piezoelectric composites of $PbTiO_3$ powder and Eccogel polymer were developed using small amounts of a semiconducting phase. These composites were poled rapidly at low voltages, resulting in properties superior to composites prepared without a conductive phase. The effect of addition of various conductive phase with different volume percentage on the dielectric and piezoelectric properties of the composite are discussed here.

• Korean Chemical Engineering Research
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• v.51 no.5
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• pp.580-586
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• 2013

In this paper, polymer composite membranes and ceramic composite membranes were prepared in order to compare differences in pervaporation performances relative to the support layers. PVDF was used for the polymer support layers, and $a-Al_2O_3$ was used for the ceramic support layers. For active layer was coated for PDMS, which is a rubbery polymer. The characterization of membranes were analysed by SEM, contact angle, and XPS. We studied performances relative to the composite membrane support layers in the ABE mixture solutions. The results of the pervaporation, the flux of the ceramic composite membrane was shown to be $250.87g/m^2h$, which was higher than that of polymer composite membranes, at $195.64g/m^2h$. However, it was determined that the separation factor of the polymer composite membranes was 31.98 which were higher than that of the ceramic composite membranes, at 20.66.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1212-1215
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• 2004

Diffraction modes of holographic grating were fabricated with polyurethane acrylates(PUA). Two types of silica (AEROSIL 200 and AEROSIL R812) were added to reduce the shrinkage of polymer matrix. It was founded that shrinkage of PUA composite film was reduced with the addition of silica. HPDLC based PUA/silica composite also showed high diffraction efficiency. The morphology of the resultant gratings was analyzed by using scanning electron microscopy(SEM) and Tg of the polymer matrix by dynamic mechanical thermal analysis(DMTA).

• Bulletin of the Korean Chemical Society
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• v.33 no.9
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• pp.2949-2954
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• 2012

Nano ZnO with an average size of 8 nm was prepared by thermal decomposition of zinc oxalate at $450^{\circ}C$. A series of based composite polymer electrolyte PEO-$LiClO_4$ and nano ZnO as a filler have been synthesized using solution cast technique, with varying the filler ratio systematically. XRD, DSC and FTIR studies have been conducted to investigate the structure and interaction of different groups in the composite polymer electrolyte. Effect of nano ZnO ceramic filler concentration on the structure of composites and their electrical properties (DC-conductivity, AC-conductivity, dielectric constant, dielectric loss and impedance) at different frequencies and temperatures was studied. Melting temperature ($T_m$) of PEO decreased with the addition of both $LiClO_4$ salt and nano ZnO filler due to increasing the amorphous state of polymer. All composite samples showed an ionic conductivity. The maximum room temperature ionic conductivity is found for $(ZnO)_{0.5}(PEO)_{12}(LiClO_4)$ composite sample. All the results are correlated and discussed.

• Composites Research
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• v.31 no.5
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• pp.192-201
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• 2018

The use of 3D printing for rapid tooling and manufacturing has promised to produce components with complex geometries according to computer designs and it is emerging as the next generation key of manufacturing. Due to the intrinsically limited mechanical/electrical properties and functionalities of printed pure polymer parts, there is a critical need to develop 3D printable polymer composites with high performance. This article gives a review on 3D printing techniques of polymer composite materials and the properties and performance of 3D printed composite parts as well as their potential applications in the various fields.

• Journal of the Korean Ceramic Society
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• v.36 no.5
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• pp.539-546
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• 1999

Absorbent polymer-cement composites were fabricated by the semi-powder mixing OPC(ordinary Portland cement) with an absorbent polymer. The effects of absorbent polymer on the mechanical properties and the hydration characteristics were observed and the polymer-cement interaction also discussed. Absorbent polymer-cement composites showed the value of total porosity of 8vol% the value of 28 days flexural strength was up to 280 Kgf/cm2 in the case of absorbent polymer-cement composite at 1 wt% absorbent polymer content and microstructure of absorbent polymer-cement composite has been observed more dense than that of OPC paste. Accordingly the permeability of compositewas improved and so the moisture resistance was also increased. Adding polymer did not retard the hydration of OPC. It was considered from the results of IR(infrared) analysis that the functional group of absorbent polymer would be changed from unidentate to bidentate during by the hydration of cement minerals.