• The International Journal of Costume Culture
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• 제5권2호
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• pp.53-65
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• 2002

Morphology of polyester fiber was physically modified by solvent treatment. PET fiber was treated with N,N-dimethylformamide (DMF) at 100, 120, $140^{circ}C$ for 10 minutes without tension. The structural changes in the morphology of DMF-induced modified PET fiber were FTIR and SEM analysis. Also dyeing behavior of DMF-treated polyester fibers with various disperse dyes was studied to detect changes of amorphous area in fine structure. DMF treatment resulted in increases in total void content, degree of crystallinity, trans isomer content, chain folding, segmental mobility and molecular packing, but it resulted in decreases in amorphous orientation, intermolecular forces and individual void size through longitudinal shrinkage, lateral welling and removal of oligomers. Void-size distribution could be estimated from the dye uptake with various sizes of disperse dyes. In contrast to the large increases in dye uptake with small dye molecules, there is no and little dye uptake with the bulkiest dye, which means that void size is bigger or smaller than the volume of each dye. Diffusion rates of dye molecules showed increases. This dyeing study revealed that the disperse dyeing is very effective method for characterizing the internal morphology of polyester fiber.

• 대한화학회지
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• 제24권3호
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• pp.266-268
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• 1980

• 청정기술
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• 제17권1호
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• pp.19-24
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• 2011

본 연구에서는 가변부피 투시창이 설치되어 있는 고압 상평형 측정 장치를 사용하여 이산화탄소의 임계온도 이상과 디메틸포름아마이드(DMF)의 임계온도 이하의 온도 범위에서 혼합물의 조성을 변화시키면서 이산화탄소와 디메틸포름아마이드 혼합물의 기포점 압력을 측정하였다. 실험적으로 측정된 기포점 압력 데이터를 Peng-Robinson 상태방정식에 상관시킴으로써 기포점 조성과 평형을 이루는 이슬점 조성을 추정하였다. 실험적으로 측정된 기포점 압력은 Peng-Robinson 상태방정식으로 계산한 결과와 매우 잘 일치하였다. 가변부피 투시창이 설치되어 있는 고압 상평형 실험장치는 고압의 압축유체 혼합물의 기포점을 매우 쉽고 빠르게 측정할 수 있는 방법이라고 할 수 있다.

• Bulletin of the Korean Chemical Society
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• 제30권11호
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• pp.2595-2602
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• 2009

Hexamer cluster of N,N-dimethylformamide(DMF) based on the crystal structure was investigated for the equilibrium structure, the stabilization energies, and the vibrational properties in the density functional force field. The geometry (point group $C_i$) of fully optimized hexamer clustered DMF shows quite close similarity to the crystal structure weakly intermolecular hydrogen bonded each other. Stretching force constants for intermolecular hydrogen bonded methyl and formyl hydrogen atoms with nearby oxygen atom, methyl C–H${\cdots}$O and formyl C–H${\cdots}$O, were obtained in 0.055 $\sim$ 0.11 and $\sim$ 0.081 mdyn/$\AA$, respectively. In-plane bending force constants for hydrogen bonded methyl hydrogen atoms were in 0.25 $\sim$ 0.33, and for formyl hydrogen $\sim$ 0.55 mdynÅ. Torsion force constants through hydrogen bonding for methyl hydrogen atoms were in 0.038 $\sim$ 0.089, and for formyl hydrogen atom $\sim$ 0.095 mdynÅ. Calculated Raman and infrared spectral features of single and hexamer cluster represent well the experimental spectra of DMF obtained in the liquid state. Noncoincidence between IR and Raman frequency positions of stretching C=O, formyl C–H and other several modes was interpreted in terms of the intermolecular vibrational coupling in the condensed phase.

• Toxicological Research
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• 제12권1호
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• pp.1-8
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• 1996

The variation in the enzyme activities of human liver usually represents the particular physiological conditions of each individuals. Thus, we investigated the variation in the activities of SOD, HR and LPO of (1) non-exposed workers (56 subjects), and (2) exposed workers to DMF (43 subjects) in synthetic leather process. Serum levels of enzyme activities of exposed workers (AST:$30.26{\pm}20.041$U/L, ALT:$32.72{\pm}23.393$U/L, GGT:$28.47{\pm}18.635$ U/L, ALP:$81.77{\pm}34.879$ U/L)were slightly higher than those in nonexposed workers (AST:$24.00{\pm}9.441$ U/L, ALT:$23.89{\pm}18.305$U/L, GGT:$21.95{\pm}17.970$U/L, ALP:$70.84{\pm}24.678$U/L), but only the level of ALT was statistically significant (p< 0.05). Serum levels of LDH, TRF and CHOL in non-exposed workers were slightly higher than those of exposed workers. However, they were not statistically significant (p > 0.05). Serum levels of HR and LPO of the exposed workers appeared to be reduced, but not those of the non-exposed workers. The SOD activities of exposed workers were also slightly higher than those of non-exposed workers, but the results were not statistically significant (p > 0.05). The level of HR was increased with age, but the SOD level was not. These results suggest that the intermittent exposure to DMF at time-weighted average (TWA) level (10 ppm/$m^3$) has affected on the activities of enzymes such as AST, ALT, TRF, but not on the generation of HR, activity of SOD. However, if high dose of DMF was used, there would be severe effects for the generation of HR and LPO.

• 대한환경공학회지
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• 제22권11호
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• pp.1985-1994
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• 2000

본 연구는 페놀의 초기 홉착량, 온도, pH가 유기용매에 의한 페놀 탈착에 미치는 영향을 조사하기 위한 것으로 methanol, acetone, N,N-dimethylformamide(DMF)를 유기용매로 사용하였다. 초기 흡착량은 166.1mg/g, 180.7mg/g, 197.9mg/g의 세 경우, 온도는 $15{\sim}55^{\circ}C$까지 $10^{\circ}C$ 간격으로 다섯 온도 조건, pH는 산성, 중성, 염기성에서의 페놀 탈착율 변화를 살펴보았다. 페놀의 탈착은 용매의 극성 모멘트와 비례하여 methanol < acetone < DMF 순으로 나타났으며, acetone과 DMF의 경우에는 탈착율이 약 90% 정도로 유사하였다. 초기 흡착량이 증가할수록 용매에 의한 페놀 탈착율은 직선적으로 감소하였으며, DMF에 의한 탈착율 감소 정도가 가장 완만한 것으로 미루어 초기 흡착량이 DMF 탈착 성능에 미치는 영향이 가장 적은 것으로 나타났다. 온도가 높아질수록 페놀 탈착도 증가하였으며, methanol의 증가폭이 가장 큰 것으로 미루어 methanol에 의한 페놀 탈착반응이 온도에 가장 민감함을 알 수 있다. 용매 pH가 높아질수록 페놀 탈착율도 증가하였으며, 특히 methanol의 경우는 pH 12에서 페놀의 탈착율이 10% 이상 급격히 증가되었으며, 이는 methanol의 탈착 능력이 pH의 영향을 가장 많이 받는 것으로 추정된다. 세 용매 중에서 methanol의 페놀 탈착율이 가장 떨어졌으나, 온도와 pH를 조절하게 된다면 acetone, DMF와 유사한 탈착율을 보였으며, methanol이 가장 저렴하기 때문에 적정한 탈착 조건을 선정 적용한다면 경쟁력있는 재생 용매로서 가능성을 지니고 있다고 판단된다.

• 한국산업보건학회지
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• 제18권1호
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• pp.80-90
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• 2008

This study was carried out to investigate the correlation of urinary NMF concentration in workers exposed to DMF and concentration of DMF in the workplace. Samples were collected in workers exposed to high dose solvent in the synthetic leather factory by using silicagel tubes for 5-15 minutes, and were analyzed by GC. Geometric mean concentrations of DMF in the workplaces were 4.67 ppm in normal operation and 63.95 ppm in high exposure operation. The concentration of case uppers and machine cleaning process were more than 100 ppm in short time. The correlation of urinary NMF in workers and DMF in workplace was statistically significant in normal operation and high exposure operation. Correlation coefficient are 0.215(p<0.05) and 0.263(p<0.05). The result implied that STEL of DMF should be established in normal operation processes as well as high exposure operation processes.

• Journal of Pharmaceutical Investigation
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• 제6권2호
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• pp.83-87
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• 1976

Microanalysis of rodenticide by visible absorption method was attempted. The following procedure was found to be very simple and to give accurate results. RH-28787 was added to dimethylformamide (DMF), and extracted after stirring for about 20 minutes in extractor $(30^{\circ}C)$. After extraction, the absorbance of DMF solution, was measured at 346 nm by using spectrophotometer. The result agrees closely with the experimentally determined value by means of the gas chromatograph.

• 한국염색가공학회지
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• 제15권4호
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• pp.8-16
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• 2003

Poly(trimethylene terephthalate)(PTT) fiber was pretreated with organic solvent/water solution of various compositions. The organic solvents used in this experiment were benzyl alcohol, n-buthanol, and N,N-dimethylformamide(DMF). Density of the fibers were investigated as a measure of crystallite region. The dye uptake increased in the order of pretreatment with hot water < untreated < 5% benzyl alcohol < 100% benzyl alcohol < 90% benzyl alcohol; hot water < untreated $\risingdotseq$ 5% butanol < 100% beutanol < 90% butanol; hot water $\risingdotseq$ 5% DMF < untreated < 90% DMF < 100% DMF. The dye uptake increases with increase of crystallinity. It seems likely that the recrystallization process during the pretreatment with organic solvent/water solutions leads to an increase in the microvoid and then a large increase in the dye uptake. Also the dyeing rate increased and the dyeing transition temperature decreased with the pretreatments. The results obtained are corresponds with the plasticization of the fiber structure formed during the pretreatrnent.

• Bulletin of the Korean Chemical Society
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• 제35권12호
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• pp.3637-3641
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• 2014

In this study, we analyzed the toxicity of mixtures of dimethylformamide (DMF) and methyl ethyl ketone (MEK) or DMF and toluene (TOL) and predicted their toxicity using quantitative structure-activity relationships (QSAR). A QSAR model for single substances and mixtures was analyzed using multiple linear regression (MLR) by taking into account the statistical parameters between the observed and predicted $EC_{50}$. After preprocessing, the best subsets of descriptors in the learning methods were determined using a 5-fold cross-validation method. Significant differences in physico-chemical properties such as boiling point (BP), specific gravity (SG), Reid vapor pressure (rVP), flash point (FP), low explosion limit (LEL), and octanol/water partition coefficient (Pow) were observed between the single substances and the mixtures. The $EC_{50}$ of the mixture of DMF and TOL was significantly lower than that of DMF. The mixture toxicity was directly related to the mixing ratio of TOL and MEK (MLR $EC_{50}$ equation = $1.76997-1.12249{\times}TOL+1.21045{\times}MEK$), as well as to SG, VP, and LEL (MLR equation $EC_{50}=15.44388-19.84549{\times}SG+0.05091{\times}VP+1.85846{\times}LEL$). These results show that QSAR-based models can be used to quantitatively predict the toxicity of mixtures used in manufacturing industries.