Spectroscopic analysis of methacrylate groups introduced on silica particle surfaces by the aza-Michael addition reaction

Kiryong Ha,Sangmi Lee 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.8

We modified silica nanoparticles with a N'-(3-trimethoxysilylpropyl)diethylenetriamine (TPDT) silane coupling agent, which has one primary and two secondary amino groups in each molecule, to introduce amino groups on silica surfaces. After surface modification of silica, we used an acrylate group containing 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHM) to introduce free radical polymerizable methacrylate groups by the aza-Michael addition reaction. Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA), liquid state 1H and 13C nuclear magnetic resonance spectroscopy (NMR) and solid state cross polarization magic angle spinning (CP/MAS) 29Si NMR were used to investigate the effects of various reaction conditions on the degree of reaction between the N-H groups of the TPDT-modified silica surface and the acrylate groups of AHM. We found that approximately 48% of the N-H groups of the TPDT-modified silica surface reacted with the acrylate groups of AHM, compared with approximately 83% of the N-H groups of pure TPDT reacting with the acrylate groups of AHM at the same reaction conditions. This lower degree of the aza-Michael addition reaction between the N-H groups of the TPDT grafted on the solid silica particle versus the N-H groups of pure TPDT, both with acrylate groups of liquid AHM, may be caused by the lower mobility of the N-H groups of the grafted TPDT on the solid silica particle and the higher steric hindrance caused by the solid silica particle.

Multiwalled carbon nanotubes and fluoroelastomer antistatic nanocomposite for automotive fuel system components

Kiryong Ha,Young Seok Lee,Seong Hwan Park,Jong Cheol Lee 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.3

Fluoroelastomer (FKM) composites, reinforced with multiwalled carbon nanotubes (MWNTs), were prepared by conventional method to determine the possibility of using MWNTs to develop an antistatic composite in automotive fuel systems. The results obtained from the composite containing 0-9 phr of MWNTs were compared. A 5 points increase in hardness was achieved with the addition of only 1 phr of MWNTs and 9 phr added FKM composite was increased 6.4MPa in tensile strength compared to the MWNTs unfilled FKM composite. In addition, electrical conductivity increased from 0 to 1.039 Scm−1 with increase in the MWNTs concentration, and the dynamic damping property was increased in the rubbery state region accordingly. These phenomena can be explained by the MWNTs networks formed in FKM matrix. This research will therefore be useful in the development of an antistatic rubber composite for fuel system components, which are deformed or vibrated while in operation.

Studies of Liquid Crystal Alignment on the Photosensitive Polyvinylfluoro-cinnamate

Kiryong Ha,Dongsoo Kim,Dong-Su Synn 한국고분자학회 2006 한국고분자학회 학술대회 연구논문 초록집 Vol.2006 No.10

Synthesis and application of reactive polymer modifiers for Asphalt

KiRyong Ha,Kiseob Hwang 한국고분자학회 2006 한국고분자학회 학술대회 연구논문 초록집 Vol.2006 No.10

Wireless Body Area Network in a Ubiquitous Healthcare System for Physiological Signal Monitoring and Health Consulting

Joonyoung Jung,Kiryong Ha,Jeonwoo Lee,Youngsung Kim,Daeyoung Kim 보안공학연구지원센터(IJSIP) 2008 International Journal of Signal Processing, Image Vol.1 No.1

Heat Treatment Effect on Anti-Tacking Properties of an Zn-stearate/TEA-stearate/Water Emulsion System

( Pei Qin ),( Jinbae Lee ),( Kiryong Ha ),( Wonsool Ahn ) 한국고무학회 2019 엘라스토머 및 콤포지트 Vol.54 No.3

Carbon master batch (CMB) rubber sheets, which are stored in stacks, are difficult to separate during reuse because of the adhesion between sheets caused by the stacked weight over time. To solve this problem, in the actual rubber product manufacturing process, various anti-tacking agents (solid powder or liquid surfactants) are applied to the sheet surface. In this study, the emulsion samples of zinc (Zn)-stearate/triethanolamine (TEA)-stearate mixtures were prepared using TEA-stearate as a surfactant, prepared using an industrially manufactured Zn-stearate powder, and their basic anti-tacking properties were studied. During the process of manufacturing emulsion, a heat treatment process and an auxiliary surfactant were introduced to improve the dispersion stability. Results showed that the heat-treated sample exhibited a significant improvement in terms of sedimentation, storage stability, and anti-tacking characteristics since the Zn-stearate particles were reduced to a smaller size by the heat-treatment than that of the original Zn-stearate powder.

실리카 나노 입자 표면에 결합된 1차 및 2차 아미노기와 3-(Acryloyloxy)-2-hydroxypropyl Methacrylate의 마이클 부가 반응에 의해 도입되는 메타크릴레이트기의 정량적 분석

이상미(Sangmi Lee),하기룡(KiRyong Ha) 한국고분자학회 2015 폴리머 Vol.39 No.2

본 연구에서는 나노 크기의 실리카 입자 표면을 1차 및 2차 아미노기를 각각 1개씩 가지는 실란 커플링제인 N-[3-(trimethoxysilyl)propyl]ethylenediamine(TPED)으로 개질한 후, 아미노기와 마이클 부가 반응이 가능한 acrylate기를 가지는 3-(acryloyloxy)-2-hydroxypropyl methacrylate(AHM)로 표면 개질하는 연구를 수행하였다. 반응온도, 투입량 및 반응시간과 같은 반응 조건들의 변화가 실리카 표면에 도입되는 methacrylate기의 양에 미치는 영향을 연구하였다. 순수 TPED와 순수 AHM을 50℃에서 5시간 반응시킨 액체-액체 반응에서는 TPED 1분자 당 존재하는 3개의 아미노기(N-H)들 중 약 85%가 마이클 부가 반응하지만, TPED로 개질한 실리카 표면에 결합한 TPED의 3개의 아미노기는 약 30% 정도만 반응하여 반응성이 매우 낮아짐을 확인하였다. In this study, we modified silica nanoparticles with N-[3-(trimethoxysilyl)propyl]ethylenediamine (TPED) silane coupling agent, which has one primary and one secondary amino groups in a molecule, to introduce amino groups on the silica surface. After modification of silica, we used 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHM) to introduce methacrylate groups by Michael addition reaction. We found about 30% of N-H groups on the TPED modified silica surface reacted with acrylate groups of AHM compared to about 85% of reaction between N-H groups of pure TPED with acrylate groups of pure AHM. This lower degree of Michael addition reaction for heterogeneous reaction between N-H groups on the solid TPED modified silica and liquid AHM compared to homogeneous reaction between pure liquid TPED and pure liquid AHM may be caused by lower mobility of grafted amino groups of TPED moiety and higher steric hindrance caused by solid silica particles.

Effects of Co-agent Type and Content on Curing Characteristics and Mechanical Properties of HNBR Composite

( Young Seok Lee ),( Kiryong Ha ) 한국고무학회 2020 엘라스토머 및 콤포지트 Vol.55 No.2

Currently, peroxide cure is a widely used cure system for rubber materials. To improve its effectivity, co-agents are used to enhance the peroxide efficiency and mechanical properties of rubber materials. Co-agents are multifunctional organic compounds that are highly reactive towards free radicals. These co-agents provide higher cross-link densities for a given peroxide concentration and improve the mechanical properties of peroxide-cured rubber composites. In this study, trimethylolpropane trimethacrylate (TMPTMA) and high vinyl 1,2-polybutadiene (HVPBD) were used as co-agents. In order to obtain a concentration that achieves a favorable balance between mechanical properties and co-agent concentration, this research investigated the effects of co-agent content on the curing characteristics, chemical structures, and mechanical properties of HNBR composites. Additionally, the heat aging properties and compression sets of HNBR composites were investigated. Based on the results, we found that the HNBR composites with TMPTMA co-agents exhibited higher Shore A hardness and 10% modulus and better heat aging resistance and compression set than that of the HVPBD co-agent. The heat aging resistance and compression set deteriorated with increasing HVPBD content.

A Context Aware System for Personalized Services using Wearable Biological Signal Sensors

Dong-oh Kang,Kiryong Ha,Jeonwoo Lee 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

In this paper, we propose a context aware system for personalized services using wearable biological signal sensors, by which a user can be provided with a personalized services via a user terminal device on the basis of information of user’"s stress level derived from biological signals measured using biological signal sensors, and usage behavioral habits of services by a user. The system of this paper is composed of a user terminal device, wearable biological signal sensors, and service providers connected with a user terminal device through external public network. Wearable biological signal sensors are connected with a user terminal device via WPAN communication technology. Stress level of a user is calculated using biological signal sensor values when a service is selected and used by a user. And, user’"s usage behavioral habits of a service are tracked, like usage time, usage duration, and usage frequency, etc. The gathered information is used to derive user’"s preference of a service. By using the system mentioned above, a user can be provided with a personalized service which is given on most preferred time, and adjusted to fit a user’"s preference. To show the feasibility of the proposed system, we apply the system to the music recommendation service.

아미노기가 도입된 셀룰로오스 나노 결정을 충전제로 사용한 친환경 폴리우레탄 나노복합체 제조 및 물성에 대한 연구

이유나(Youna Lee),박서숙(Seosuk Park),하기룡(KiRyong Ha) 한국고분자학회 2020 폴리머 Vol.44 No.3

본 연구에서는 바이오 폴리올과 석유계 폴리올을 질량비 3:7 비율로 혼합한 폴리올을 4,4"-methylenebis (phenyl isocyanate)(MDI)와 반응시켜 친환경 폴리우레탄 나노복합체를 제조하는 연구를 수행하였다. 또한 3-aminopropyltriethoxysilane(APS) 실란 커플링제를 사용하여, 셀룰로오스 나노 결정(cellulose nanocrystal, CNC) 표면에 -NH₂기를 도입하여 충전제로 사용하였다. 표면 개질된 CNC 충전제가 폴리우레탄 나노복합체의 물성에 미치는 영향을 열 중량 분석기(TGA), 만능재료시험기(UTM) 및 동적기계분석기(DMA)를 사용하여 체계적으로 분석하였다. CNC표면에 도입된 -NH₂기는 MDI의 -NCO기와 계면에서 우레아 결합을 형성하여 순수 CNC를 충전제로 사용한 폴리우레탄 나노복합체보다 인장강도와 탄성률이 더 많이 증가되는 것을 확인하였다. In this study, a polyol mixture of bio-polyol and petroleum-polyol in a mass ratio of 3:7 was reacted with 4,4"- methylenebis(phenyl isocyanate) (MDI) to prepare an eco-friendly polyurethane (PU) nanocomposite. Also, using 3-aminopropyltriethoxysilane (APS) silane coupling agent, -NH₂ group was grafted onto the cellulose nanocrystals (CNCs) surfaces, which was used as fillers. We studied the effects of surface modified CNC fillers on the mechanical properties of PU nanocomposites using thermogravimetric analysis (TGA), universal testing machine (UTM) and dynamic mechanical analyzer (DMA). The -NH₂ groups grafted on the CNC surface can form urea bonds with -NCO groups of MDI at the interface, which increased the tensile strength and modulus of PU nanocomposites more than those of the pristine CNC as fillers.