저온열처리에 의한 Poly(ethylene terephthalate)의 결정화에 관하여

국윤환,송주호 한국섬유공학회 1985 한국섬유공학회지 Vol.22 No.2

In order to study the crystalline morphology and crystallization mechanism of PET annealed at low temperature, the amorphous PET film, quenched from the melt, was annealed at 90∼120$^{\circ}C$ with and without tension for various times. The properties of annealed PET film were measured by density gradient tube, polarizing microscope, infrared spectrometer, X-ray diffractometer and thermal analyzer. The following results were obtained; 1. The crystalline morphology of annealed PET at low temperature was not fringed micellar or bundle-like but spherulitic. 2. Crystallites became more perfect with the increase of annealing time. 3. The rate of crystallization was rapid and the dimensions of crystal growth became larger with the increase of annealing temperature. 4. Local crystallization via chain folding proceeded at low temperature.

유기용매/ 물의 가성소오다 용액에서 폴리에스테르 직물의 알칼리 가공에 관한 연구

국윤환,최창남 한국섬유공학회 1984 한국섬유공학회지 Vol.21 No.2

In order to know the effect of solvent on the rate of weight loss, polyester fabrics were treated in caustic soda solution of organic solvents/water, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, acetone, N,N'-dimethylformamide and tetrahydrofuran. The following results were obtained. The rate of weight loss was increased by treating fabrics in organic solvent/water caustic soda solution. In alcoho/water caustic soda solution, it is considered that the effect of solvation and that of nucleophilicity of alkoxide ion were large at the lower and higher alcohol content in water, respectively. Generally, the tensile strength of the fabric treated in organic solvent/water caustic soda solution was decreased, especially in PrOH added solution. The degree of crystallinity of the fabric treated in organic solvent/water caustic soda solution was slightly decreased or increased, compared with that of the fabric treated in aqueous caustic soda solution.

국산면과 미면의 물리적 성질에 관한 비교연구(제1보) -섬유장, 섬도, 강도 및 천연연에 관하여-

국윤환 한국섬유공학회 1973 한국섬유공학회지 Vol.10 No.4

To study comapatively the physical properties of Korean cotton and American upland cotton, physical properites such as maximum length, effective length, percentage short fiber, percentage dispersion, fineness, tensile strength, and spirality of Korean cotton and American upland cotton have been mesured. The reults of this study are as follows: (1) The maximum length of Korean cotton is within the range of 24.85mm to 30.00mm, the effective length 22.15mm to 27.90mm, the prcentage short fiber 12.06% to 26.72%, the precentage dispersion 13.77%, to 29.05%, the fineness 3.3$\mu\textrm{g}$/in. to 4.9$\mu\textrm{g}$/in., the tensile strength 65.303(1,000 psi) to 78.772(1,000 psi), and the spirality 51.2conv./cm to 60.6conv./cm. (2) Classifying the physical properties of Korean cotton by its producing district, the maximum length, the effective length, and the fineness of MogPo 6 are 30.00mm, 27.90mm and 3.3$\mu\textrm{g}$/in., respectively, the percentage short fiber of Yeocheon 12.06%, the percentage dispersion 13.77%, the tensile strength of Dalsung 78.772(1,000 psi), the spirality of Changyeong 60.6conv./cm, and each of them shows the best values in their field of the physical properties of Korean Cotton. (3) The maximum length of American upland cotton is within the range from 22.35mm to 30.00mm, the effective length 19.55mm to 26.80mm, the percentage short fibre 13.80%, the percentage dispersion 24.83% to 34.03%, the fineness 2.9$\mu\textrm{g}$/in., the tensile strength 65,649 (1,000 psi) to 85,107 (1,000 psi), and the spirality 47.9conv./cm to 59.7 conv. (4) As shown above, Mogpo 6 of Korean cotton is American upland cotton Good Middling in maximum length, effective length, effective length and fineness, and is approximate to it in spirality.

용제를 이용한 PET의 가연가공

양갑승,국윤환 한국섬유공학회 1990 한국섬유공학회지 Vol.27 No.4

나일론6 용융물의 다이팽윤에 관한 연구

김영성,국윤환 한국섬유공학회 1986 한국섬유공학회지 Vol.23 No.6

Rheological properties and die swell of nylon6 melts were measured by varying the shear rate, length/diameter of die, and temperature. Die swell was theoretically investigated on the concept of the recovery of strain and the rearrangement of velocity and compared with the experimental results. Die swell due to the recovery of strain was larger than that of rearrangement of velocity. Die swell increased with the shear modulus of nylon6 melts, and normal stress differences were evaluated from this relation. Die swell increased greatly in the range of lower shear rate but did not increased significantly in the higher shear rate.

Structure and Physical Property of the Blends of Ultra-high Molecular Weight Polyethylene

조재환,국윤환,황윤언,Jo, Jae-Hwan,Guk, Yun-Hwan,Hwang, Yun-Eon The Korean Fiber Society 1989 한국섬유공학회지 Vol.26 No.2

Gel films were prepared from the mixtures of ultra-high molecular weight polyethylene(UHME PE) and high density polyethylene (HDPE) in a decalin solution. To investigate the formation of mixed crystals in the blends, i.e.cocrystallization, melting behaviors of the gel films and the slowly cooled films from melt were analyzed by differential scanning calorimetry. The slowly cooled films from melt as well as gel films showed the single melting peaks and this was ascribed to the formation of mixed crystals. The heat of fusion of the slowly cooled films from melt was nearly linear to the weight percent of UHMW PE and HDPE but gel films showed a minimum value. However, no significant lattice changes were found in the X-ray diffraction of gel films. The tensile moduli of gel films decreased with the increase of weight percent of HDPE and the yield stresses were almost constant in the intermediate weight percent of UHMW PE and HDPE.

직물구김의 예측 시뮬레이션

김의화,국윤환 한국섬유공학회 1998 한국섬유공학회지 Vol.35 No.6

Simulation of the fabric wrinkle recovery from the structural parameters and mechanical properties of fabrics is performed by two kinds of methods, i.e., the neural network method which is based on the Generalized Delta Rule and the multiple linear regression method. The effects of structural parameters and characteristic values of a fabric such as hysteresis and resilience on the wrinkle recovery were more predominant than the constituent fiber or yarn parameters and other characteristic values of a fabric.

Vinylidene Fluoride-Trifluoroethylene 공중합체의 상전이촉매작용에 의한 탈불화수소화

조재환,송하율,국윤환,Jo, Jae-Hwan,Song, Ha-Yul,Guk, Yun-Hwan 한국섬유공학회 1995 한국섬유공학회지 Vol.32 No.1

Films of vinylidene fluoride - trifluoroethylene (VDF-TrFE ) copolymer were dehydrofluorinated in aqueous sodium hydroxide solutions by phase transfer catalysis(PTC). Conjugated C=C double bonds in the polymer back-bone were bonds in the dehydrofluorination of VDF-TrFE copolymer. The color of film became brown and finally black with rigid double bonds during the PTC reaction. It was found from UV/VIS spectroscopic measurements that the length of conjugated double bonds of dehydrofluorinated VDF-TrFE copolymer was longer than that of dehydrofluorinated poly(vinylidene fluoride) . It was ascribed to the reaction activity due to the difference of solubility parameter between the sample and reaction solution. Thermal behavior by DSC analysis showed that the dehydrofluorination occurred at least in the crystal surfaces as well as in the amorphous chains.

직물의 압축성과 태

김의화,이대훈,국윤환,Kim, Ui-Hwa,Lee, Dae-Hun,Guk, Yun-Hwan 한국섬유공학회 1988 한국섬유공학회지 Vol.25 No.6

Compressional experiments with the various plain woven fabrics were made by using the Kawabata's system. Objective hand evaluation for some worsted woven fabrics were also performed by the system. It was predicted that the thickness of the fabric is changed logarithmically as the load acting on the fabric. The exponents of the logarithmic compressional curves can be decided by the properties of constituent yarn, the fabric count and the surface roughness of the fabric. In case of the worsted plain woven fabrics for the men's summer suit, their compressibilities have quite effect on the total hand value and the primary hand values except Fukurami.

콜타르 핏치의 화학적 개질

이홍범,김찬,양갑승,국윤환,Lee, Hong-Bum,Kim, Chan,Yang, Kap-Seung,Kook, Yoon-Hwan 한국섬유공학회 1995 한국섬유공학회지 Vol.32 No.4

In order to introduce a functionality to coal tar pitch, dienophiles such as p-benzoquinone(BQ) and maleic anhydride(U) were used in the chemical modification reaction. The coal tar pitch was reacted with BQ or MA at 160℃ under nitrogen atmosphere. Thermal behavior of'the reaction product was examined by sofiening point measurement and thermogravimetric analysis(TGA) under nitrogen atmosphere. TGA results revealed that the weight loss of the reaction product is reduced with the amount of BQ used in the reaction. The result comes fiom the formation of intermolecular cross links between the pitch molecules. The sofiening point of the reaction products increased with the amount of the BQ or MA used in the reaction. BQ was more effective than MA in increasing the sofiening point of coal tar pitch. The coal tar pitch ryacted with 200wt% BQ showed dimensional stability with heat treatment up to 500℃. The concentration ewut of BQ and MA on solubility in various solvents was tested by sequential extraction method. The insoluble fiaction of the reaction product increased with increase of BQ, whereas M showed an opposite effect. On the basis of courier transform-infiared(FT-lR) spectroscopic result, BQ acts not only as a dienophile of Diels-Alder reaction agent but also as a crosslinking agent, whereas H acts mainly as a dienophile.