분지형 폴리프로필렌의 비등온결정화 거동 연구

윤경화(Kyung Hwa Yoon),신동엽(Dong Yup Shin),김연철(Youn Cheol Kim) 한국고분자학회 2012 폴리머 Vol.36 No.2

장쇄분지(long chain branch, LCB)를 가지는 분지화된 폴리프로필렌(polypropylene, PP)이 세 종류의 분지 제(branching agent)를 이용하여 고상(solid state)에서 제조하였다. 분지화된 PP의 화학구조, 비등온결정화 거동 및 복합점도를 적외선분광기(FTIR), 시차주사열용량분석기(DSC), 광학현미경 그리고 동적유변측정기(ARES) 를 이용하여 관찰하였다. 분지화된 PP의 화학구조는 3100 cm-1에서 나타나는 분지제의 =C-H 신축진동을 이용하 여 확인하였다. PP-D-0-3과 PP-F-0-3의 경우 순수 PP와 비교하여 용융온도에 큰 변화를 보이지 않은 반면 HQ를 사용한 경우에는 용융온도의 감소를 나타내었다. 이는 분지화 반응보다 분해반응이 우세하여 나타나는 현상으 로 해석되고, 복합점도의 감소를 통해 확인하였다. 분지화된 PP의 비등온결정화 거동은 Avrami 방정식을 이용하 여 분석하였다. PP의 Avrami 지수는 3의 값을 나타내었고, DVB와 FS로 처리된 분지화 PP의 경우는 3보다 약간 작 은 값을 나타내었다. Kissinger 방법에 의해서 계산된 분지화 PP의 활성화에너지는 순수 PP의 25 kJ/mol과 큰 차 이를 보이지 않았다. Branched polypropylenes (PP) with long chain branch were prepared by solid state reaction with three different branching agent of 0.3 wt% content. The chemical structures, non-isothermal crystallization behavior and complex viscosity of the branched PP were investigated by FTIR, DSC, optical microscope, and dynamic rheological measurement. The chemical structure of the branched PP was confirmed by the existence of =C-H stretching peak of the branching agent at 3100 cm-1. There was no distinct change in melting temperature in case of PP-D-0-3 and PP-F-0-3, but PP-H-0-3 indicated a decrease in melting temperature. The decrease in melting temperature was interpreted by the fact that the degradation reaction of PP was more dominant than branched reaction, and confirmed by a decrease in complex viscosity. The non-isothermal crystallization behavior of the branched PP was analyzed using by Avrami equation. The Avrami exponent of PP was 3, and the values of the branched PP with DVB and FS were below 3. The activation energy of PP calculated by Kissinger method was 25 kJ/mol, and there were no big difference in activation energies of the branched PPs compared to PP.

개질 폴리프로필렌/나노필러 복합체의 유변학적 특성 및 발포거동

윤경화(Kyung Hwa Yoon),이종원(Jong Won Lee),김연철(Youn Cheol Kim) 한국고분자학회 2013 폴리머 Vol.37 No.4

이축압출기(twin screw extruder)를 이용하여 용융상태에서 furfuryl sulphide를 분지제로 개질 폴리프로필렌(modified polypropylene, m-PP)을 제조하였고, 층상 실리케이트와 다중벽 탄소나노튜브(multi-walled carbon nano tube, MWCNT)와의 m-PP/나노필러 복합체를 제조하였다. m-PP의 화학구조와 열적 특성은 적외선분광기(FTIR), 시차주사열용량분석기(DSC)를 이용하여 관찰 하였다. M-PP의 화학구조는 3100츠-1에서 나타나는 분지제의 =C-H 신축진동피크를 이용하여 확인하였고, 용융온도는 큰 변화를 보이지 않았지만 결정화온도는 10-20℃ 가량 증가하였다. m-PP/나노필러 복합체의 유변학적 특성과 분산성 및 발포거동은 동적유변측정기, X-선 회절분석기(XRD), 주사/투과전자현미경(SEM/TEM)을 이용하여 관찰하였다. m-PP/나노필러 복합체의 낮은 주파수 영역에서의 복합점도와 용융탄성이 증가하였으며, 전단담화(shear thinning) 효과 또한 증가하였다. 순수 PP와 비교할 때 m-PP와 m-PP/나노필러 복합체의 발포 거동 개선효과가 우수한 것을 확인하였다. Modified polypropylene (m-PP) was fabricated by furfuryl sulphide (FS) as branching agent and m-PP/nano-filler composites were prepared with silicate and multi-walled carbon nanotube (MWCNT), using a twin screw extruder. The chemical structures and thermal properties of the m-PP were investigated by FTIR and DSC. The chemical structure of the m-PP was confirmed by the existence of =C-H stretching peak of the branching agent at 3100cm-1. There was no district change in melting temperature in case of m-PP, but a certain increase in crystallization temperature was notified and the increase was in the range of 10-20℃. The rheological properties, filler dispersion and foaming behaviors of the m-PP/nano-filler composites were investigated by dynamic rheometer, X-ray diffractometer (XRD) and scanning/trans-mission electron microscope (SEM/TEM). m-PP/nano-filler composites showed a high complex viscosity at a low fre-quency, an increase in melt elasticity, and a high shear thinning effect. Compared to pure PP, m-PP and m-PP/nano-filler composites were sufficient to enhance the foaming behavior.

용융중합에 의한 분지형 폴리카보네이트의 유변학적 특성 연구

최수정(Su Jung Choi),윤경화(Kyung Hwa Yoon),김희승(Hee Seung Kim),유승윤(Seung Yoon Yoo),김연철(Youn Cheol Kim) 한국고분자학회 2011 폴리머 Vol.35 No.4

폴리카보네이트(polycarbonate, PC)에 화학적 구조가 다른 두 가지의 분지제를 첨가하여 용융중합으로 분지형 폴리카보네이트(branched PC, B-PC)를 합성하였다. 분지제의 함량은 0.001∼0.005 mol% 내에서 조절하였다. 합성된 PC의 화학구조는 FTIR, 1H NMR과 13C NMR 스펙트럼을 이용하여 확인하였으며, 분자량, 유리전이온도 및 분해온도는 GPC, DSC와 TGA를 이용하여 측정하였다. Phloro type의 분지제를 가지는 B-PC의 분자량이 낮은 값을 보여주었으며, 유리전이온도는 분자량에 따라 증가하였다. 두 형태의 B-PC 모두 선형 PC와 비교하였을 때 낮은 주파수(frequency) 영역에서 복합점도(complex viscosity)가 높게 나타났고, shear thinning 현상이 크게 나타났다. Shear thinning의 정도를 표시하는 power law index(n)는 선형회귀분석에 의해 계산되었고 0.483∼0.996 범위의 값을 보여주었다. Phloro 타입의 B-PC가 높은 shear thinning 경향을 보였으며 이들 B-PC의 유변학적 특성은 동적유변측정기를 이용하여 측정하였다. The branched polycarbonates (B-PCs) with two different branching agents were synthesized from melt polymerization. The contents of branching agent were in the range of 0.001∼0.005 mol%. The chemical structure of the synthesized PC was determined by FTIR, 1H NMR, and 13C NMR, spectroscopy. The molecular weight, glass transition and degradation temperatures were determined by GPC, DSC, and TGA. The molecular weight of the phloro type B-PC had a lower value than the other one, and the glass transition temperature increased with molecular weight. Compared with linear PC, the rheological properties of the B-PC indicated an increase of complex viscosity in the low frequency region and shear thinning tendency. Power law index(n) representing shear thinning was calculated by linear regression and the values were in the range of 0.483~0.996. The rheological properties of the B-PCs were measured by a dynamic rheometer.

분지형 폴리프로필렌/실리케이트 복합체의 유변학적 특성 연구

프러산터 ( Prashanta Dahal ),윤경화 ( Kyung Hwa Yoon ),김연철 ( Youn Cheol Kim ) 한국공업화학회 2011 공업화학 Vol.22 No.6

고상(solid state) 반응과 용융(melt state) 반응을 이용하여 장쇄분지(long chain branch, LCB)를 가지는 분지화된 폴리프로필렌(branched polypropylene, LCB-PP)을 제조하였다. 분지제(branching agent)로는 divinylbenzene (DVB), 1,4-benzenediol (RES), furfuryl sulphide (FS)가, LCB-PP/실리케이트 복합체를 제조하기 위해서는 층상 실리케이트가 사용되었다. LCB-PP의 화학구조, 열적특성, 유변학적 특성을 적외선 분광기(FT-IR), 시차주사열용량분석기(DSC, TGA), 그리고 동적유변측정기(ARES)를 이용하여 분석하였다. LCB-PP의 화학구조는 3100 cm -1에서 나타나는 분지제의 =C-H 신축진동을 이용하여 확인하였다. DSC와 TGA의 결과로부터 고상반응보다 용융반응이 LCB-PP 제조에 보다 효과적이었고, 유변학적 특성을 통하여 추가 확인되었다. 분지제 중에서는 FS가 가장 효과적이었다. LCB-PP의 경우 낮은 전단속도 영역에서 점도와 shear thinning tendency가 증가하였고, G`-G`` plot으로부터 탄성특성의 증가와 LCB의 도입에 의한 용융상태의 불균일성(heterogeneousness)을 확인할 수 있었다. LCB-PP/실리케이트 복합체의 실리케이트 함량에 따른 유변학적 특성을 관찰하였다. 실리케이트의 함량이 5 wt%인 경우 면찰 담화(shear thinning)와 G`-G`` plot에서의 기울기 변화가 가장 크게 나타났다. Branched polypropylenes (LCB-PP) with a long chain branch were prepared by the solid-state and molt-state reaction. Divinylbenzene (DVB), 1,4-benzenediol (RES), and furfuryl sulphide (FS) were used as branching agents of fabricate LCB-PP/silicate composites. Chemical structures, thermal properties, and rheological properties of the LCB-PP were determined by FT-IR, DSC, TGA, and dynamic rheometer (ARES). The chemical structure of the LCB-PP was confirmed by the existence of =C-H stretching peak of the branching agent at 3100 cm -1. From DSC and TGA results, the melting reaction was more effective than the solid state reaction in the manufacture of LCB-PP, which was additionally certified by rheological properties. Based on rheological properties, FS was the best for branching efficiency of PP. Compared to PP, LCB-PPs indicated an increase of complex viscosity in the low frequency and shear thinning tendency, and G`-G`` plot represented an increase in elasticity and the heterogeneousness in a melt state. Rheological properties of LCB-PP/silicate composites were observed with the silicate content. When 5 wt% silicate was added in LCB-PP, distinct changes in the shear thinning and the slope of G`-G`` plots were observed.

폴리카보네이트의 저분자량 화합물 및 휘발성 유기물에 대한 접촉추출 영향

최수정 ( Su Jung Choi ),윤경화 ( Kyung Hwa Yoon ),황인혜 ( In Hye Hwang ),이창용 ( Chang Young Lee ),김희승 ( Hee Seung Kim ),유승윤 ( Seung Yoon Yoo ),김연철 ( Youn Cheol Kim ) 한국공업화학회 2010 공업화학 Vol.21 No.5

비스페놀A계 폴리카보네이트 내에 잔류하는 휘발성 유기화합물(VOCs)과 저분자량 화합물 함량 변화에 대한 연구가 케톤류(아세톤, 펜타논, 부타논)의 용매를 사용한 접촉추출 실험으로 수행되었다. 접촉추출 전 시료의 저분자량 화합물의 양은 2.6 wt%이었으나 아세톤으로 접촉추출 한 시료의 경우 0.96 wt%, 펜타논으로 접촉추출 한 시료의 경우는 1.53 wt%로 나타났고, 아세톤의 경우가 저분자량화합물 추출에 효율적임을 알 수 있었다. 휘발성 유기화합물 농도변화 확인을 위해서 GC-Mass를 이용하였다. GC-Mass 실험 결과 휘발성 유기물로 염화메틸렌, 톨루엔 등이 확인되었고, 정량한 결과 펜타논의 경우가 아세톤의 경우보다 VOCs 처리에 효율적이었다. VOCs와 저분자량 화합물의 효율적 처리를 위해서는 아세톤과 펜타논의 혼합사용이 유리할 것으로 판단되고 혼합용매 사용결과 부피비로 50:50에서 최적의 결과를 나타내었다. A study on the volatile organic compounds (VOCs) and low molecular weight (LMW) amount which is contained within bisphenol A polycarbonate (PC) was performed by the solvent extraction with ketone type solvents (acetone, butanone, pentanone). The LMW amount of untreated PC was 2.6 wt%, but the values of treated samples with acetone and pentanone were 0.96 and 1.53 wt%, respectively. Acetone is a more effective solvent than pentanone on the LMW extraction. Methylene chloride (MC) and toluene were certified and quantified by GC-Mass experiments, and the quantitative results indicated the fact that the pentanone was the effective solvent on VOC extraction. Focused on the change of VOCs and LMW amount, the use of co-solvent might be more useful, and the experimental results of co-solvent extraction showed that the optimum condition was 50:50 volume percent.

면역 적격자에서 급성 폐렴으로 발현된 폐실질 및 기관지를 침범한 Mycobacterium avim 감염

이유진 ( Yu Jin Lee ),김동현 ( Dong Hyun Kim ),윤경화 ( Kyung Hwa Yoon ),김미영 ( Mi Young Kim ),정승욱 ( Seung Wook Jung ),이병기 ( Byung Ki Lee ),김연재 ( Yeon Jae Kim ) 대한결핵 및 호흡기학회 2010 Tuberculosis and Respiratory Diseases Vol.69 No.4

The global number of Mycobacterium avium complex (MAC) pulmonary infection is increasing. Patients with preexisting lung disease or who are immunodeficient are at the greatest risk for developing MAC infection. Endobronchial lesions with MAC infection are rare in the immunocompetent host. However, there have been an increasing number of reports of an immunocompetent host being afflicted with various manifestations of MAC infection. We report a case of pulmonary and endobronchial MAC infection presenting as an acute pneumonia in a 59-year-old female without preexisting lung disease or immunodeficiency.

지역사회 획득 폐렴환자의 중증도평가에서 혈청 코티졸의 유용성

박민수 ( Min Su Kim ),박훈표 ( Hun Pyo Park ),윤경화 ( Kyung Hwa Yoon ),김연재 ( Yeon Jae Kim ),김미영 ( Mi Young Kim ),김은영 ( Eun Young Kim ),배명남 ( Myoung Nam Bae ),배상묵 ( Sang Mook Bae ) 대한결핵 및 호흡기학회 2011 Tuberculosis and Respiratory Diseases Vol.70 No.1

소비자 친화형 포크리프구조의 매니퓰레이터의 원격제어에 관한 연구

김성일(Seong-Il Kim),김희진(Hee Jin Kim),강다비(Da-Bi Kang),한성현(Sung-hyun Han),윤경화(Kyung-Hwa Yoon) 제어로봇시스템학회 2022 제어로봇시스템학회 국내학술대회 논문집 Vol.2022 No.6

일개 2차 의료기관에서의 비결핵성 마이코박테리아 분리비율 및 폐질환의 임상 경과

이재광 ( Jae Kwang Lee ),권혁용 ( Hwuck Young Kwon ),권종규 ( Jong Kyu Kwon ),이화정 ( Hwa Jeong Lee ),이동욱 ( Dong Wook Lee ),이유진 ( Yu Jin Lee ),윤경화 ( Kyung Hwa Yoon ),송도영 ( Do Young Song ),이병기 ( Byung Ki Lee ),김연 대한결핵 및 호흡기학회 2009 Tuberculosis and Respiratory Diseases Vol.67 No.3

Background: To examine the recovery rate of nontuberculous mycobacteria (NTM) from respiratory specimens and the clinical course of NTM pulmonary disease at a 700-bed secondary hospital. Methods: This study analyzed the results of 843 acid-fast bacilli (AFB) culture-positive respiratory specimens from 650 subjects collected between May 2003 and April 2008. In addition, the clinical course of NTM pulmonary disease, diagnosed using criteria established by the American Thoracic Society, was examined. Results: There were 67 (7.9%) NTM isolates recovered from 52 (8.0%) subjects. Among the 535 AFB smear-positive specimens, 34 (6.3%) NTM isolates were recovered. There were 33 (10.7%) NTM isolates were recovered from 308 AFB smear-negative specimens. Of 52 subjects with isolated NTM, M. intracellulare was the most common species at 73.1% (n=33), followed by M. kansassi (n=7), M. abscessus (n=2), M. fortuitum (n=2), and M. avium (n=1). Sixteen (30.8%) patients had NTM pulmonary disease and the most common causative organism was M. intracellulare (n=14, 87.5%). Of these, 6 cases attained negative conversion in culture, 4 cases failed to attain negative conversion because of poor cooperation or expiration from complicated underlying lung disease, and 5 cases were transferred to a higher-grade hospital. Conclusion: The recovery rate of NTM from respiratory specimens was relatively low and the most common species was M. intracellulare. Patients with NTM pulmonary disease showed variable clinical outcomes.