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핵자기공명 분광법을 이용한 PC/PBT 블렌드의 에스테르 교환에 관한 반응속도 연구
이금향(Keumhyang Lee),신지영(Jiyoung Shin),유효연(Hyo-Yeon Yu),곽동환(Donghwan Kwak),김창근(Chang Keun Kim),안상두(Sangdoo Ahn) 한국고분자학회 2016 폴리머 Vol.40 No.3
¹H NMR 분석방법을 이용하여 여러가지 가열 조건하에서 폴리카보네이트/폴리(부틸렌 테레프탈레이트) (PC/PBT) 블렌드의 에스테르 교환반응 속도에 관하여 조사하였다. 일반적으로 고분자 배합비를 산출하는데 사용하는 TGA 측정 과정에서, PBT의 열분해 온도에 이르기 전에 교환반응이 매우 활발히 일어난다는 것을 확인하였으며, 이에 따라 상대적으로 높은 열분해 온도를 가지는 PC의 함량이 원래 혼합된 것보다 적은 것처럼 관측된다는 것을 알았다. 200, 250, 300℃에서 가열시간을 증가시키면서 PC/PBT(50:50 wt%) 블렌드와 분말 혼합물의 에스테르 교환반응률을 측정하였고 이를 통하여 반응속도 상수를 결정하였다. 분석한 모든 온도에서 블렌드의 반응속도 상수가 더 크게 관측되었으며, 250℃ 이상의 고온에서는 짧은 가열시간에도 교환반응이 상당히 진행된다는 것을 확인할 수 있었다. The kinetic properties of transesterification reaction in polycarbonate/poly(butylene terephthalate) (PC/PBT) blends were investigated by ¹H NMR spectroscopy under various annealing conditions. During the TGA analysis which is commonly used for composition analysis of polymer blends, the exchange reaction occurred very actively before it reached the thermal decomposition temperature of PBT. Hence, the composition of PC in thermogram seemed to be less than the original value. The kinetic constants of transesterification in PC/PBT (50:50 wt%) blend and powder mixture at 200, 250, and 300℃ were calculated from the degrees of transesterification obtained while increasing the annealing time. It was found that the kinetic constants for the blend were greater than the mixture, and the exchange reaction was considerably progressed even in the short annealing time.
복합고분자 PC/PBT 배합비 산출 및 기계적물성 분석기술
이금향(Keumhyang Lee),곽동환(Donghwan Kwak),윤성구(Sunggoo Yun),신민철(Minchul Shin),황덕형(Duckhyoung Hwang),안상두(Sangdoo Ahn) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11
Polymer blends and composites are widely used in automobile parts. In these compounds, the most important factor is the blend ratio. So, we have carried out the quantitative analysis for the PC/PBT blend using TGA and new analysis method of NMR spectroscopy. A further study, we also studied prediction model equations of mechanical properties of tensile, bending and impact strength from the compositional results. In conclusion, this advanced analytical technique will help us to develop new products and deal with field claims in automobile industry.
박대규,이금향 한국경영교육학회 2000 경영교육연구 Vol.21 No.-
This study on clinical nurse has been developed through several research hypothesis. But there is few comparative study on between the organizational commitment(ORC) and professional commitment(PRC). This thesis is investigated its basic theory and their relationship between organizational commitment which is based on the attachment to the organization, and professinal commitment which is given much weight in the occupational worth and self-conceit for technical job. The research meterials data were collected from 383 nerses who are for over than 1 year and working at five general hospitals and three hospitals in affiliation to the medical colleges of universities in kang-won province, and also this data were gotten by self-reporting questionnaire from march 15, 1999 to march 27, 1999. The instruments used for this study are the likert-type scale for organizational commitment which was developed by mowday and professional commitment scale developed by hall&morrow. The wording and sentences used for this questionnaire are modified and revised properly for correspondence with medical languages of the hospital organization and nursing words. The data were analysis by frequency, percentage, two-way ANOVA, pearson's correlation coefficient, multiple regression, and factor analysis with SPSS-PC+ program.
핵자기공명분광법을 이용한 하이드라자이드계 POM 포름알데히드 저감제의 함량분석
임유진(Yoojin Lim),정찬호(Chan Ho Jeong),이금향(Keum Hyang Lee),김유라(Yura Kim),유효연(Hyo-Yeon Yu),안상두(Sangdoo Ahn) 한국고분자학회 2019 폴리머 Vol.43 No.2
Polyoxymethylene(POM)은 포름알데히드를 단량체로 하는 고분자로, 물리적 물성이 우수하나 열적 안정성은 낮아 쉽게 분해가 일어나며 이로 인해 포름알데히드를 발생한다. POM으로부터 방출되는 포름알데히드의 배출량을 줄이기 위해 이와 반응성이 좋은 질소 화합물들이 첨가제로 사용되고 있다. 본 연구에서는 <SUP>1</SUP>H NMR 분광법을 이용하여 저취(low odor) POM 공중합체에 첨가된 포름알데히드 저감제인 하이드라자이드계 화합물의 상대적 함량을 간단하게 분석하는 기법을 개발하였다. 분석 시료에 과량의 포름알데히드를 가하여 포함된 전체 하이드라자이드기를 NMR 스펙트럼에서 분석이 용이한 하이드라존으로 변환하는 방법을 적용하였고, 이러한 분석법을 통하여 95% 수준의 정확도로 하이드라자이드 첨가제의 정량분석이 가능함을 확인하였다. Polyoxymethylene (POM) is a polymer composed of formaldehyde as a monomer and has excellent physical properties. However, it has low thermal stability and is easily decomposed, thereby generating formaldehyde. In order to reduce the emission of formaldehyde from POM, nitrogen compounds are used as a reducing agent. In this study, a simple method of analyzing the content of hydrazide compounds, a formaldehyde reducing agent, added to a low odor POM copolymer was developed using <SUP>1</SUP>H NMR spectroscopy. An excess amount of formaldehyde was added to the analytical sample to convert the entire hydrazide group to a hydrazone which is easy to analyze in 1H NMR spectrum. It was confirmed that the quantitative analysis of hydrazide additive was possible with accuracy of 95% level.