폐 폴리부틸렌테레프탈레이트 복합재료의 충격성과 난연성에 관한 연구 : A Study on Impact and Flammability Properties of Composite Using Waste Poly(butylene-terephthalate)

홍기헌 金泉大學 2017 논문집 Vol.38 No.-

Poly (1,4-butylene terephthalate) (PBT) has been used in various industries, especially in automotive, electrical and electronic fields. The PBT resin offers an excellent balance of mechanical and electronical properties as important engineering plastics should show. But these materials have some problems producing waste and caught fire easily. To solve the waste problems, recycling of plastics have been studied. Unfortunately, the recycling leads to decrease the mechanical properties, especially impact strength. But the materials for electronic and electrical fields needs to flame retardancy. In this study, we found out the proper recipe of PBT resin for excellent flame retardancy and impact strength using wasted PBT resin. The wasted PBT resin composite for excellent flame retardancy and impact strength was used brominated epoxy type flame retardant and thermoplastic polyester elastomer, respectively. The materials made by this study have 75.4J/m impact strength, UL-94 V0 flame retardancy, and 28% limiting oxygen index. The other mechanical properties such as tensile strength, flexural strength and modulus were higher than 95% of the PBT composite used virgin resin.

5V 스피넬 양극 소재 LiNi0.5Mn1.5O4의 전기화학적 및 구조적 특성

홍헌표, 조병원, 나병기 충북대학교 산업과학기술연구소 2022 산업과학기술연구 논문집 Vol.36 No.1

본문참고

생분해성 PLA를 이용한 안경테의 적용 및 그의 물성 연구

홍기헌 ; 김용석 김천대학교 2011 김천대학교 논문집 Vol.32 No.-

Poly (lactic acid) (PLA) is well known as a biodegradable thermoplastic polyester with good physical properties. In recent year, environmental deterioration caused by synthetic plastic is serious. So, PLA is a one way to solve the problem. This study investigated the optimum conditions of injection moulding and the properties of the biodegradable eyeglass frame, such as tensile strength, elongation, mould shrink-age, dyeability and elastic deformation. Biodegradable eyeglass frame (temple) can be made with injection moulding machine in the optimum conditions. Materials were used PLA only and plasticizer modified PLA, respectively. Tensile strength and elongation of PLA was around 600kgf/cm' and 6 10% respectively. Those of plasticizer modified PLA was 560kgf/cm' and 25% respectively. PLA temple has brittle characteristics not flexibility. But the property was not significant with respect to the various injection moulding conditions. And tensile strength decreased and elongation increased with addition of the plasicizer. Dyeability was excellent for all sam-ples. After high deformation, the frame can not recover completely. Elastic recovery of plasticizer modified PLA was better than that of PLA only.

사출성형 조건에 따른 PBT수지의 물성변화 연구

홍기헌 김천대학교 2005 김천대학교 논문집 Vol.26 No.-

Poly(1,4-butylene terephthalate) (PBT) resin has been used in various industries, especially in automotive, electrical and electronic fields.

로진을 함유하는 에폭시 수지의 합성과 접착특성 연구

홍기헌 김천대학교 2009 김천대학교 논문집 Vol.29 No.-

Epoxy Resin is well known as a structural material, adhesive, and coating mate-rial. Some copolymers combined with glycidylmethacrylate (GMA) have been used as adhesives. And the rosin has also been used as a tackifier for adhesives. GMA has epoxy group and can be cured with diamine. In this research, the styrenic-monomer containing rosin moiety (SMR) was synthesized by reacting with rosin and 4-vinylbenzylchloride (4-VBC). And the copolymer was synthesized with SMR and GMA by radical polymerization. Also, styrene (St) –GMA copolymer was synthesized to compare between the two copolymer systems. These copolymers were cured with hexamethylenediamine (HMD) and measured adhesive strength. The trace of curing was confirmed by IR spectra. The strength of poly (SMR-co-GMA) was higher than that of poly (St-co-GMA). Accordingly, the SMR-GMA copolymer can be used in adhesives and coating materials.

PEN / PET 공중합체와 블렌드의 특성에 관한 연구

홍기헌 김천대학교 2004 김천대학교 논문집 Vol.25 No.-

Poly(ethylene 2,6-naphthalate-co-terephthalate)s (PEN/PET copoly-mers) were synthesized by two-stage esterification and polycondensa-tion reaction. PEN/PET blends were prepared with twin screw extruder. The compositions of PEN/PET copolymer and blend were determined by 'H NMR spectroscopy. The PEN contents in the copolymer were higher than those of the feed ratio. Intrinsic Viscosity (IV) of the all polymers decreased with increasing PEN contents. For the copolymers, the glass transition temperature (Tg) increased with increasing PEN contents. Crystallization temperature (Tc) and melting temperature (Tm) were not detected for the copolymers contain-ing 25.0, 43.8, and 64.9mole% of PEN contents. And these copolymers had not characteristic peak of the crystalline polymers in X-ray diffrac-tion pattern. This means that those copolymers are amorphous poly-mers. For the blends, Tg increased with increasing PEN contents. Tc and Tm of the polymers containing 40.0 and 60.0wt% of PEN contents were two. This means that the blend polymers have two different crystalline structure. Also, this was supported in X-ray diffraction pattern.

안경렌즈용 폴리카보네이트 수지의 사출성형 횟수에 따른 물성 연구

홍기헌 김천대학교 2012 김천대학교 논문집 Vol.33 No.-

Polycarbonate (PC) is well known as a high impact strength and transparent thermo-plastic resin for eyeglasses lens. In recent year, the usage of PC lens has been increased for sports goggles, sunglasses, polarized eyeglasses, orthoptic eyeglasses and progres-sive eyeglasses lens. Especially, PC has 150 C of Glass Transition Temperature (Tg) and92kg-cm/cm' of Impact Strength (IS). So this resin is very good material for eyeglasses lens. But plastic is not degrade in natural conditions, so plastic cause the environmental dete-rioration. The method to solve the problem is making biodegradable resin or recycling of material. This study investigated some physical properties of PC with respect to recycle times with injection moulding machine. Tensile Strength (TS), Impact Strength, Glass Transition Temperature, and Heat Deflection Temperature (HDT) were decreased with increasing recycle times and this phenomena caused by thermal degradation and hydrolysis during processing. TS and HDT were decreased slowly to 2 cycle times and sharply from 3 cycle times and IS is similar with TS but decreased more sharply that of TS. The change of Tg was small with respect to cycle times compared with the other properties. Consequently, PC can be used by 2 cycle times without large drop of properties for some applications.

대학생들의 안전교육 및 안전의식에 관한 연구

홍기헌 ; 윤석호 김천대학교 2014 김천대학교 논문집 Vol.35 No.-

The purpose of this study is to figure out current status of safety education until today and safety consciousness of university students. For this study, the 300 university students were taken among freshmen and sophomores in gimcheon university. Furthermore it is try to realize the necessity of additional safety education in universi-ty and the unification of emergency call numbers. The results are as follows: 1. It was showed that the most students prefer unified emergency call number not divided. 2. Marine accident safety education was lowered compared with other life safety ducations such as fire, earthquake, and traffic safety educations. 3. It was showed that many university students wish additional actual safety educa- tion in university as academic subjects. 4. University students consider that Sewol passenger ship accident was caused by eficient of vocation and safety frigidity of crew and company staffs. And in order to revent this kind of accident, crew vocation should be built up, students safety duca-tion should be strengthened and government agency should watch severely the hip remodelling

자외선/과산화수소 고도산화공정에 의한 하수 2차 처리수 중의 용존유기물 분해에 미치는 부유물질과 과산화수소 농도의 영향

안규홍,이석헌,안석,김기팔,정민우,맹승규 대한상하수도학회 2002 상하수도학회지 Vol.16 No.3

Secondary effluent of activated sludge process was treated by UV/H_2O_2 advanced oxidation process to investigate the effect of suspended matter and H_2O_2 concentration. With low dosage of UV radiation, the concentration of the dissolved organic compounds measured as DOC could be increased with and without hydrogen peroxide. It was suggested that the cause of DOC increase in treated samples was the decomposition of suspended microbial particles and the incomplete oxidation of dissolved organic compounds. The removal of suspended solid significantly enhanced the degradation of DOC in both UV and catalyzed UV oxidation. Color and odor of secondary effluent was effectively removed. Turbidity was decreased by oxidation and the particle size distribution was shifted to lower range. With increased H_2O_2 dosage (30∼120mg/l), the removal of DOC was enhanced. To obtain the required quality meeting the regulated level for water reuse, additional treatment for turbidity rejection was required.

한국어 자료 사전 구축을 위한 데이터 구조와 노드 구성 형태

박기홍,이태헌,정정후 群山大學校 1996 論文集 Vol.23 No.-

Korean analysis systems require a large-scale data dictionary and the built dictionary is very frequently searched during the morphological analysis. For the more efficient system, we must construct the dictionary that has fast size- independent search time and makes efficient use of storage which preserves the basic characteristics of Trie. As regards both side of search time and memory space, we know that search time of double Trie structure using double array is suitable for construction of Korean data dictionary, and the type which we separate each mode by phoneme-unit is more useful to Korean processing.