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나재운,정영일,조종수,Na, Jae Un,Jeong, Yeong Il,Jo, Jong Su Korean Chemical Society 2000 Bulletin of the Korean Chemical Society Vol.21 No.4
Multiblock copolymers consisting of poly( g-benzyl L-glutamate) (PBLG) as the hydrophobic part and poly(ethylene oxide) (PEO) as the hydrophilic part (GEG) were synthesized and characterized. GEG polymeric micelles were prepared by the dialysis technique. Particle size distributions based on intensity,volume, and number-average were 22.6 $\pm$ 11.9 nm, 23.5 $\pm$ 4.6 nm, and 23.7 $\pm$ 37 nm, respectively. It was observed that par-ticle size and size distribution of GEG polymeric micelles changed significantly with the choice of initial sol-vent. Transmission electron micrographs (TEM) showed the polymeric micelles to be spherically shaped, with sizes ranging from 20 nm to 40 nm in diameter. Fluorescence spectroscopy measurements suggested that GEG block copolymers wereassociated in water to form polymeric micelles, and the critical micelle concentrations (CMC) value of the block copolymers was 0.0094 g/L. Further evidenceof micelle formation of GEG block copolymers and limited mobility of the PBLG chain in the core ohe micelle was obtained with 1 H NMR in D2O.
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김선일,김구열,임형미,이봉우,나재운,Kim, Seon Il,Kim, Gu Yeol,Im, Hyeong Mi,Lee, Bong U,Na, Jae Un Korean Chemical Society 2000 Bulletin of the Korean Chemical Society Vol.21 No.8
Crack-free hard coating siIica films were prepared by sol-gel processfrom twokinds of silicon alkoxide (tetra-ethoxysilane and methyltrimethoxysilane) and two kinds of alcohol (methanol and isopropyl alcohol) with an acid catalyst,acetic acid. A silicate framework of the precursor solution was investigated by infrared spectros-copy (IR) in the process of hydrolysis and condensation. Theextent of the condensation in the intermediates was elucidated by gel permeation chromatography (GPC) and 29Si-NMR spectroscopy. The hard coating films werecharacterized by IR,scanning electron microscope (SEM), thermo gravimetric analyzer (TGA) and dif-ferential scanning calroimeter (DSC). The synthetic condition for the crack-free and transparent silica film for-mation was optimized interms of starting materials for the precursor solution as well as preparation method of the silica film.
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최혜영 ( Choe Hye Yeong ),김태형 ( Kim Tae Hyeong ),손소희 ( Son So Hui ),공병기 ( Gong Byeong Gi ),최창용 ( Choe Chang Yong ),김동곤 ( Kim Dong Gon ),장미경 ( Jang Mi Gyeong ),노홍균 ( No Hong Gyun ),나재운 ( Na Jae Un ) 한국키틴키토산학회 2004 한국키틴키토산학회지 Vol.9 No.1
본 연구에서는 천연자원으로부터 α-, β- 및 γ-chitin을 분리하였고, 이를 이용하여 α-, β- 및 γ-chitosan을 제조하였다. 원재료의 화학적 조성과 chitin과 chitosan의 일반성분을 분석하였으며 상대점도측정과 Kina 적정법을 이용하여 점도평균분자량과 탈아세틸화도를 측정하였고 FT-IR spectrophotometer, soild state CP/MAS ^(13)C NMR spectrophotometer 에 의해 α-, β- 및 γ-chitin과 chitosan의 제조를 확인하였다. α-, β- 및 γ-chitin의 각각의 분자량이 701, 612 그리고 524 kDa으로 측정되었으며 α-, β-및 γ-chitosan의 분자량이 603, 607, 329 kDa임을 확인하였다. α-, β-및 γ-chitin의 탈아세틸화도가 21.8%, 3?.3% 그리고 44.7%로 확인되었고 α-, β- 및 γ-chitosan의 탈아세틸화도가 97.1%, 99.2%, 그리고 96.6% 임을 확인하였다. Chitin의 FT-IR 스펙트럼에서 amide I에서의 흡수 밴드가 α-chitin에 있어서는 이중선으로, β-chitin에 있어서는 단일선으로 나타났으며 γ-chitin에서는 α-, β-chitin의 중간형태로 나타났음을 확인하였다. Chitosan의 FT-IR 스펙트럼에서 탈아세틸화 반응에 의해 amide Ⅰ과 amide Ⅱ의 흡수 피크가 현저히 감소하였음을 확인하였다. Chitin의 Solide state CP/MAS ^(13)C NMR 스펙트럼결과에서 α-chitin의 경우 C3과 C5의 피크가 각각 73과 75 ppm에서 나타났으며 β-chitin은 74 ppm에서 단일선으로 나타났고, γ-chitin의 경우 C3과 C5의 흡수피크가 α-chitin과 유사한 형태의 피크를 나타내었다. Chitosan의 Soilde state CP/MAS ^(13) NMR 스펙트럼에서 C1~C6가 잘 나타나 있고, 탈아세틸화 반응에 의해 메틸탄소 및 카르보닐 탄소가 거의 나타나지 않았다. α-, β- and γ-chitin were isolated from crab shell, squid pen, beetles cuticles by acid, alkali treatment and α-, β- and γ-chitosan were prepared from α-, β- and γ-chitin. Chemical compositions of raw materials and elemental of chitin and chitosan were analyzed. A weight-average molecular weight and degree of deacetylation (DDA) were determines by viscometry and Kina titration. Its structural characterization was analyzed by FT-IR spectrophotometer and solid state CP/MAS C NMR spectrophotometer. A molecular weight of α-, β- and γ-chitin were determined by viscometer resulting in 701. 612, and 524, kDa, respectively. A molecular weight of α-, β- and γ-chitosan were calculated with 603., 607 and 329 kDa, respectively. The DDA of α-, β- and γ-chitin were 21.8%, 32.3% and 44.7%, respectively. The DDA of α-, β- and γ-chitosan were 97.1%, 99.2% and 96.6%, respectively. At the FT-IR spectra of chitin, α-, β- chitin. And at the FT_IR sectra of chitosan, absorption band of amide I and amide H decreased because of the deacetylation of chitin, where as the absorption band of amine group was newly formed. From solid state CP/MAS C NMR spectra of chitin, two signals appeared at around 73 and 75 ppm assigned to C3 and C5 carbon atoms in α-chitin are sharply resolved, the signals of C3 and C5 in β-chitin shows singlet at around 74 ppm. In case of γ-chitin, two signals show at around 73 and 75 ppm assigned to C3 and C5 carbon atoms. From solid stat CP/MAS C NMR spectra of chitosan, the carbon of the C1-C6 positions were cleared identified and peaks of CH_3 and C=0 decreased significantly because of the deacetylation
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