Thermal, dielectric, and rheological properties of aluminum nitride/liquid crystalline copoly(ester amide) composite for the application of thermal interface materials

Sinh, Le Hoang,Hong, Jeong‐,Mi,Son, Bui Thanh,Trung, Nguyen Ngoc,Bae, Jin‐,Young Wiley Subscription Services, Inc., A Wiley Company 2012 Polymer composites Vol.33 No.12

<P><B>Abstract</B></P><P>In this article, thermally conductive and relatively low dielectric constant polymer matrix composites of an aluminum nitride filler (AlN) and a novel liquid crystalline copoly(ester amide) (LCP) were prepared via a solution blending method in the presence of a phosphate containing dispersant. The viscosities, thermal conductivities, and dielectric properties of the prepared AlN/LCP composites were investigated as a function of AlN loading. Our experimental results demonstrated that the AIN/LCP composite with AlN concentration of 50 wt% had 2.5 times higher thermal conductivity than pure LCP (2.020 and 0.817 W/mK for composite with 50 wt% of AlN and pure LCP, respectively), but its dielectric constant remained at low level, i.e., < 9.0 at frequency of 900 Hz. In addition, viscosities of AlN/LCP pastes in the <I>N</I>‐methyl‐2‐pyrrolidinone solvent remained at acceptable levels with the high AlN loading of 50 wt%. The morphologies of the prepared composites were also investigated by scanning electron microscopy. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers</P>

A Novel Wholly Aromatic Liquid Crystalline Epoxy Monomer Based on 2,7-Naphthalene Mesogen: Synthesis and Curing with Aromatic Diamine

Le Hoang Sinh,신승한,임동국,Nguyen Ngoc Trung,Bui Thanh Son,배진영 한국고분자학회 2013 Macromolecular Research Vol.21 No.10

A novel all aromatic 2,7-naphthalene-based liquid crystalline epoxy (LCE) was synthesized successfully in this study. The thermal transition of the synthesized LCE was characterized by wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), and polarized optical microscopy (POM). The characterization showed that the LCE had a low melting temperature of 65 oC and was in a nematic state in temperature range of 65-75 oC. The curing reaction between LCE and 4,4'-diaminodiphenylsulfone (DDS) was investigated, using 2-methylimidazole (2MI) as the reaction catalyst. Upon the addition of 1 phr of 2MI, the curing temperature was dramatically decreased from 227 to 128 oC, which is 99 oC lower than that of a reaction without the use of a catalyst system.

Enhanced photocatalytic degradation of reactive blue 19 using zeolitic imidazolate framework-8 composited with Fe3O4/MnO2 heterojunction

Van Thuan Le,Hoang Sinh Le,Vy Anh Tran,이상화,Van-Dat Doan,주상우,Yasser Vasseghian 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.115 No.-

The present study offers a novel recyclable Fe3O4/MnO2/ZIF-8 heterojunction photocatalyst for the degradationof reactive blue 19 (RB19) under visible light irradiation. The catalyst was facilely synthesized bydepositing Fe3O4/MnO2 nanocomposite onto the surface of ZIF-8 and characterized by field-emissionscanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy,X-ray diffraction, nitrogen adsorption–desorption isotherms and UV–vis spectroscopy. Morphology and structure characterization of the prepared photocatalyst indicated that polyhedralZIF-8 (ca. 500 nm) was coated by MnO2/Fe3O4 nanorods. The synergy effect of Fe3O4/MnO2/ZIF-8 compositeexhibited an excellent photocatalytic activity toward RB19 degradation of 99.5 % after 60 min of irradiationdue to high surface area and heterojunction formation. According to scavenger tests, thephotodegradation of RB19 dye over Fe3O4/MnO2/ZIF-8 was mainly contributed by OH and O2reactiveradicals. The kinetic study showed that the catalytic degradation of RB19 on Fe3O4/MnO2/ZIF-8 was betterdescribed by the first-order kinetic model. The new catalyst was easily recovered using an external magneticfield because of its magnetic properties. Besides, Fe3O4/MnO2/ZIF-8 showed high recyclability andstability, maintaining a high removal efficiency of 91.3 % even after ten repeated cycles. The overallresults indicated that the fabricated composite can be used as an efficient photocatalyst for treatingorganic dyes in wastewater.

Enhanced adsorption of cationic and anionic dyes using cigarette butt-based adsorbents: Insights into mechanism, kinetics, isotherms, and thermodynamics

Tran Thi Kieu Ngan,Le Van Thuan,Nguyen Tien Hoang,Doan Van Dat,Vasseghian Yasser,Le Hoang Sinh 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.7

The present study provides an eco-friendly and economical way to recycle discarded cigarette butts (CBs). The raw CBs were treated with NaOH (CB-B) and integrated with chitosan (Cs), and further applied as an adsorbent for the removal of synthetic dyes. Two common cationic dyes of methylene blue (MB) and crystal violet (CV) and one anionic dye of reactive blue 19 (RB 19) were selected as model adsorbates. The study results revealed that CB-B showed a high adsorption ability toward cationic dyes, while the CB-B/Cs composite exhibited a stronger affinity for the anionic RB 19. The adsorption of all selected dyes onto CB-B and CB-B/Cs was a spontaneous exothermic process, conforming to the pseudo-first-order kinetic and Langmuir isotherm models. The maximum adsorption capacities for MB, CV and RB 19 at pH of 7, an adsorbent dosage of 4, and a temperature of 25 °C were 89.85, 82.41, and 304.49 mg/g, respectively. The primary adsorption mechanism was physical adsorption with the participation of electrostatic attraction. The CB-based adsorbents displayed high reusability, maintaining more than 75% after four consecutive cycles of reuse. This study demonstrates the promising application potential of CB-based adsorbents for treating synthetic dyes in wastewater. The conversion of CBs into a useful high-value material has special significance for environmental engineering.

Freestanding, Fiber-Based, Wearable Temperature Sensor with Tunable Thermal Index for Healthcare Monitoring

Trung, Tran Quang,Le, Hoang Sinh,Dang, Thi My Linh,Ju, Sanghyun,Park, Sang Yoon,Lee, Nae-Eung Wiley (John WileySons) 2018 Advanced Healthcare Materials Vol.7 No.12

Micro-Fibril Cellulose as a Filler for Glass Fiber Reinforced Unsaturated Polyester Composites: Fabrication and Mechanical Characteristics

Cuong Manh Vu,Dinh Duc Nguyen,Le Hoang Sinh,최형진,Tien Duc Pham 한국고분자학회 2018 Macromolecular Research Vol.26 No.1

The waste produced by bamboo stick production processing was collected from a Vietnamese craft village and used as a source of microfibril cellulose (MFC) for a filler of unsaturated polyester (UP) resin based composites in this study. A mixture of MFC in UP was obtained by directly introducing the bamboo pulp into UP resin followed by a grinding process using a ball-grinding machine. A master batch method was also adopted for composite preparation, in which a high-content solution of MFC in UP resin was first fabricated and then diluted to prepare another solution with the desired content. Morphology and mechanical characteristics of UP resin based composites were investigated. Effect of different methods of preparation, such as hand lay-up and vacuum bagging methods, on the mechanical properties of glass fiber reinforced UP resin composites was also examined, showing that the tensile strength of composite materials with 0.3 wt% MFC was increased by 10.24% (for the hand lay-up method) and 19.62% (for the vacuum bagging method) when compared with the pristine composite material. The flexural strength increased from 192.40 MPa to 208.63 MPa and the impact strength increased by 19.6% from 158.28 kJ/m2 to 186.84 kJ /m2 for the hand lay-up method.

가용성 방향족 액정 폴리에스테르와 아세틸렌 말단기 함유 열경화성 수지의 복합화 연구

조영곤(Young Gon Cho),레황신(Hoang Sinh Le),박민아(Min A Park),배진영(Jin Young Bae) 한국고분자학회 2011 폴리머 Vol.35 No.2

방향족 액정 폴리에스테르는 열방성 액정 중합체의 대표적인 예로 지금까지 구조-물성 관계가 많이 연구되었다. 본 연구에서는 유기 용매에 녹일 수 있는 가용성 방향족 액정 폴리에스테르를 합성하고 아세틸렌 말단기를 갖는 열경화성 수지와 복합화하여 제반 물성을 비교하였다. 가용성 방향족 액정 폴리에스테르는 6-hydroxy-2-naphthoic acid, terephthalic acid, isophthalic acid 및 4-aminophenol을 단량체로 하여 에스테르 및 아미드 교환 반응에 기초로 한 축합 중합법을 이용하여 합성하였다. 아세틸렌 말단기를 갖는 열경화성 수지는 4-ethynylaniline과 terephthaloyl dichloride, isophthaloyl dichloride, 4,4`-biphenyldicarbonyl dichloride 등과 각각 반응시켜 합성하였다. 가용성 방향족 액정 폴리에스테르와 열경화성 수지를 용액 블렌딩하고 열처리하여 복합체를 제조하였으며, 복합체의 열적 안정성, 열팽창계수, 유전특성 등을 조사하였다. Liquid crystalline aromatic polyesters (LCPs) are representative examples of thermotropic liquid crystalline polymers, whose structure-property relationships have been the subject of many researches. In this study, we synthesized organo-soluble liquid crystalline aromatic polyesters, and their composites with acetylene-terminated thermoset resins were prepared and characterized. Soluble LCPs were synthesized by employing 6-hydroxy-2-naphthoic acid, terephthalic acid, isophthalic acid, and 4-aminophenol as monomers via condensation polymerization based on transesterfication and transamidation. Acetylene-terminated thermoset resins were synthesized by the reaction of 4-ethynylaniline with erephthaloyl dichloride, isophthaloyl dichloride or 4,4`-biphenyldicarbonyl dichloride. We prepared the soluble LCP/thermoset composites by solution blending followed by thermal treatment. The thermal stability, thermal expansion coefficient, and dielectric properties of the composite were studied.

Maximizing volumetric energy density of all-graphene-oxide-supercapacitors and their potential applications for energy harvest

Kim, Hyuk Joon,Lee, Seul-Yi,Sinh, Le Hoang,Yeo, Chang Su,Son, Yeong Rae,Cho, Kang Rae,Song, YoonKyu,Ju, Sanghyun,Shin, Min Kyoon,Park, Soo-Jin,Park, SangYoon Elsevier 2017 Journal of Power Sources Vol.346 No.-

<P><B>Abstract</B></P> <P>Graphene has attracted widespread attention for supercapacitor applications thank to their excellent conductivity, mechanical flexibility, chemical stability and extremely high specific surface area. Here, all-graphene-oxide-supercapacitors were developed from two reduced graphene oxide (rGO) films as electrodes and one graphene oxide (GO) film as separator. The supercapacitors were then treated with 4M sulfuric acid at temperatures around 80 °C. By this treatment, the sulfuric acid molecules were physically intercalated into both rGO and GO films, which were confirmed by significant decrease intensity of characteristic peaks of sulfuric acid in Raman spectra. These sulfuric-acid-intercalated GO films can function as both quasi-solid-state electrolytes and separators. The average capacitance values measured at 100 mV s<SUP>−1</SUP> of the thermally wetted supercapacitor at 84 °C is improved 93.7 times higher than that of the as-prepared all-graphene-oxide-supercapacitor. The maximum capacitance of 266 F cm<SUP>−3</SUP> is obtained at scan rate 10 mV s<SUP>−1</SUP> for the thermally wetted supercapacitor at 84 °C. To the best of our knowledge, this is the highest specific capacitance that has ever been reported for a graphene oxide-based supercapacitor. Importantly, being in a quasi-solid-state, the energy storage performance of supercapacitors are persistent over several thousand cycles, making it very much unlike other carbon-based supercapacitors.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Quasi-solid-state all-graphene-oxide-supercapacitors were developed for the first time. </LI> <LI> Thermal wetting of the supercapacitors with H<SUB>2</SUB>SO<SUB>4</SUB> around 80 °C produces quasi-solid-state. </LI> <LI> A large volumetric capacitance of 266 F cm<SUP>−3</SUP> at a scan rate of 10 mV s<SUP>−1</SUP>. </LI> <LI> Energy storage performances of the supercapacitors are persistent over several thousand cycles. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Preparation and characterization of silicone resin nanocomposite containing CdSe/ZnS quantum dots

Trung, Nguyen Ngoc,Luu, Quynh‐,Phuong,Son, Bui Thanh,Sinh, Le Hoang,Bae, Jin‐,Young Wiley Subscription Services, Inc., A Wiley Company 2012 Polymer composites Vol.33 No.10

<P><B>Abstract</B></P><P>We report the preparation of the core/shell cadmium selenide/Zinc sulfide quantum dots (CdSe/ZnS QDs)‐silicone resin nanocomposite through the solution‐mixing method, followed by thermal hydrosilylation. After dispersing QDs into Dow Corning two‐component silicone resins (OE6630A and OE6630B at 1:4 mixing ratio by weight), the resins were cured at 150°C for 1.5 h to produce QD‐silicone resin nanocomposites. The curing behavior of the silicone resins resulting from the thermal hydrosilylation was studied using differential scanning calorimetry (DSC). The properties of the QD‐silicone resin nanocomposites were investigated by ultraviolet–visible (UV–vis), fluorescence, confocal laser scanning microscopy (CLSM), atomic force microscopy (AFM), and thermogravimetric analysis (TGA) measurements. The QDs that contain trioctylamine (TOA) as the original ligand can poison the Pt catalyst in the resins and inhibit the curing process by increasing the exothermic peak temperature, at which a lower heat of hydrosilylation is observed. Incorporating a small amount of CdSe/ZnS QDs (0.1 wt%) can greatly improve the thermal stability of the silicone resins. Moreover, CdSe/ZnS QDs tend to form clusters that are relatively homogeneously distributed in a cured silicone resin, offering good optical properties of 11.2 lm W<SUP>−1</SUP> luminous efficiency and 14.6% photoluminescence conversion efficiency (PCE) in light emitting device (LED) test. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers</P>

Large-Scale Conductive Yarns Based on Twistable Korean Traditional Paper (Hanji) for Supercapacitor Applications: Toward High-Performance Paper Supercapacitors

Heo, Young-Jung,Lee, Ji Won,Son, Yeong-Rae,Lee, Jong-Hoon,Yeo, Chang Su,Lam, Tran Dai,Park, Sang Yoon,Park, Soo-Jin,Sinh, Le Hoang,Shin, Min Kyoon Wiley (John WileySons) 2018 Advanced Energy Materials Vol.8 No.27