Properties of PVDF and PMMA Blends Films Prepared by Thermal Casting

이중규,김성훈,강호천,박상호,Lee, Jung-Gyu,Kim, Seong-Hun,Kang, Ho-Chun,Park, Sang-Ho The Korean Fiber Society 2010 한국섬유공학회지 Vol.47 No.5

Polyvinylidene fluoride (PVDF)/Polymethylmethacrylate (PMMA) blended films were optimized by changing the PMMA concentration in PVDF/PMMA blends for use as protective sheets for photo-voltage cells and modules. Films of poly(vinylidene fluoride) (PVDF) and poly(methyl methacrylate) (PMMA) blends were prepared by thermal extrude casting. The rheological properties, chemical structure, crystalline behavior, thermal, morphology, optical properties and contact angle of the PVDF/PMMA blend films were examined by RDS, FTIR, XRD, DSC, TGA, SEM and color spectrometry. The PVDF/PMMA blend containing 30 wt.% PMMA showed good performance for potential applications as the protective sheet in photo-voltage cells and modules. The ${\alpha}$ and ${\beta}$ crystalline phases in the films decreased and increased, respectively, with increasing PMMA content. The shear viscosities increased with increasing PMMA content. The melt temperature ($T_m$) and crystalline temperature ($T_c$) of the blends decreased with increasing PMMA content.

열처리 방법에 따른 표고버섯의 이화학적 특성 및 영양학적 분석

이중규(Jung-Gyu Lee),김광일(Kwang-Il Kim),황인국(In-Guk Hwang),유선미(Seon-Mi Yoo),민상기(Sang-Gi Min),최미정(Mi-Jung Choi) 한국식품영양과학회 2015 한국식품영양과학회지 Vol.44 No.6

본 연구는 열수 침지, 증기 및 볶음 처리가 표고버섯에 미치는 이화학적 분석 및 영양성분 분석을 통해 최적 열처리 조건을 확립하고자 진행하였다. 소비자들이 상품을 평가할 때 1차적으로 먼저 관찰되는 색도와 경도를 측정하고 추가로 pH 측정 등으로 인한 이화학적 결과로 최적 조건을 선정한 뒤에 그 조건들에 대해서 영양학적 및 미생물 검사를 실시하였다. 색도는 열처리 시간이 길어질수록 색의 변색 정도가 증가하여 뚜렷한 차이를 나타내었다. pH 값은 열수 침지 처리의 경우 pH 증가량이 가장 높았으며 처리 시간이 지속될수록 pH가 증가하는 경향을 나타내었다. 다른 처리군의 경우 일정 시간의 처리 시간 이후에는 유의적인 차이를 보이지 않았다. 경도에서는 열수 침지와 볶음 처리의 경우 1분 이내의 열처리만으로도 경도가 감소하는 경향을 보였으며, 증기처리의 경우 1분 동안 경도가 유지되는 결과를 보였다. 일반성분 분석 결과는 증기 처리가 가장 원물에 가까운 결과를 나타냈다. 유기산 함량은 증기 처리에서 유기산 함량 감소율이 가장 낮았다. 또한 3분간 증기 처리를 하였을 때 미생물의 사멸 효과가 가장 높았다. 열수 침지 처리나 볶음 처리의 경우 전체적으로 증기 처리한 시료에 비해서 영양성분 함량이 줄어드는 경향을 나타냈다. 따라서 표고버섯을 증기 처리방법으로 열처리하는 것이 다른 열처리군에 비해서 최적으로 나타났다. 하지만 본 연구에서는 물리화학 및 영양학적 성분의 변화만을 분석하였기 때문에 실제 식품 산업이나 공정에 적용하기 위해서는 대용량 처리 시에 발생하는 문제들과 관련된 추가적인 연구를 필요로 할 것이다. In the food industry, thermal treatment is an important process for extending shelf-life of foods. However, heating process affects the physicochemical, nutritional, and microbial properties of foodstuff such as color, texture, pH, and proximate compositions. This study was conducted to select an optimal thermal treatment by observing physicochemical, nutritional, and microbial effects of shiitake mushrooms with different thermal treatment methods. Shiitake mushrooms were washed and sliced equally (5 cm×0.5 cm×0.5 cm) and then heat-treated by three methods. Samples were heated in 100°C boiling water, steamed for 10 min, or pan fried at 130°C for 4 min. Total color difference values showed significantly increasing tendency with treatment time. For pH values, boiling water-treated mushrooms showed increasing tendency according to increased thermal treatment. For the results of hardness, boiling water or pan frying-treated mushrooms showed reduced tendency within 1 min. In the case of steam-treated mushrooms, hardness values were maintained for 1 min. Organic acid contents of steam-treated sample showed the lowest value among treatments. For microbial counts, steam-treated samples for 3 min showed the lowest value. Consequently, the results of this study suggest that steam treatment could be the optimal thermal treatment to minimize quality loss of shiitake mushrooms.

PET 필름의 이축연신에 따른 물성변화 연구

이중규(Jung Gyu Lee),박상호(Sang Ho Park),김성훈(Seong Hun Kim) 한국고분자학회 2010 폴리머 Vol.34 No.6

PET 필름의 물성을 연구하기 위하여 PET의 Tm보다 높은 다양한 온도에서 압출 후, 18℃로 급냉하였고, 종방향(MD)과 횡방향(TD)으로 각기 다른 연신비 및 다양한 열고정 온도로 제조되었다. 압출 온도, 연신비, 열고정 온도에 따른 PET 필름의 열수축 거동, 밀도, 결정화거동 및 황학적 물성 등의 변화에 대하여 고찰한 결과 MD와 TD 방향의 열수축률은 열처리온도와 압출 온도가 감소함에 따라 증가하였고, 융해열(△H)과 예비융점(Tm`)의 경우 열처리온도와 압출 온도의 증가와 함께 증가하였다. 수평균 분자량과 고유점도는 압출 온도가 증가함에 따라 감소하였고, 인장강도와 탄성률의 경우 연신비가 증가함에 따라 증가하였으나, 열처리온도를 증가하였을 때에는 감소하는 경향을 보였다. 연신 방향과 두께 방향의 굴절률은 연신비와 열처리온도가 증가함에 따라 증가함을 확인하였다. To investigate the properties of PET films, PET films were extruded at various temperature above Tm and quenched at 18℃ for amorphous sheet, and stretched along a direction defined as the machine direction (MD) with a transverse direction (TD) above Tg at various stretching ratios and then annealed at various temperatures produced by SKC PET line. Thermal shrinkage of MD and TD increased with decreasing annealing temperature and extruding temperature, and increasing stretching ratio. The degree of crystallinity, density, heat of fusion (△H) and pre-melting point (Tm`) increased with increasing annealing temperature and extruding temperature. Number average molecular weight (Mn) and intrinsic viscosity decreased with increasing extruding temperature, Tensile strength and modulus increased with increasing stretching ratio, however decreased with increasing annealing temperature. Reflective index of both stretching and thickness direction increased with increasing stretching ratio and annealing temperature.

고령자용 식품개발을 위한 함침기술과 연화제 개발 및 나노코팅 기술의 응용

이상윤(Sang-Yun Lee),이중규(Jun-Gyu Lee),이윤정(Yun-Jung Lee),최미정(Mi-Jung Choi) 한국식품영양과학회 2017 식품산업과 영양 Vol.22 No.2

재활용 폴리에스터 칩의 물성 향상 연구

최연주,이중규,김성훈,임기섭,이주형,이준희,Choi, Yeon-Joo,Lee, Jung-Gyu,Kim, Seong-Hun,Lim, Ki-Sub,Lee, Joo-Hyung,Lee, Jun-Hee 한국섬유공학회 2011 한국섬유공학회지 Vol.48 No.2

To improve the physical properties of recycled polyester chips, virgin PET chips were compounded with the ratio of 20 wt%, 40 wt%, and 70 wt%. Recycled PET chips blended with virgin PET chips exhibited decreased molecular weights and intrinsic viscosities compared with 100% recycled PET chips and virgin PET chips, and this was caused by thermal and hydrolytic decomposition. End-group contents and MFI both increased in the blended PET chips. As the virgin PET chip contents increased in the recycled PET chips, the melting temperature tended to increase. Recycled PET chips exhibited a higher crystallization temperature compared with virgin PET chips. Morphologies of recycled PET films were analyzed by scanning electron microscopy (SEM). Yellowing of recycled PET chips resulted from intramolecular cross-linking and oxidation reactions. As virgin PET chips were compounded with recycled PET chips, yellowing was reduced. The ash contents were increased in the recycled PET chips which were blended with virgin PET chips. As recycled PET chip contents were similar to those of virgin PET chips, the ash contents were the highest in the experimental materials.

보건소 정보화시스템의 도입에 영향을 미친 요인

도영경,이중규,박기동,김창엽,김용익,이진용,Do, Young-Gyoung,Lee, Jung-Gyu,Park, Gi-Dong,Kim, Chang-Yup,Kim, Yong-Ik,Lee, Jin-Yong 대한예방의학회 2003 예방의학회지 Vol.36 No.4

Objectives : This study was conducted to review the diffusion process and factors affecting the adoption of the Health Center Information System (HIS). Methods : Data were collected from POSDATA (private company), MOHW, other Ministries and local governments. To specify the date of adoption, supplementary information was collected from 40 health centers. The following three kinds of factors were analyzed. Internal factors included type, size, and innovativeness of health centers. Community factors were composed of population sire, economic status, and level of education. Organizational environmental factors consisted of information score of the municipalities, financial support of the from central government, and the neighborhoodness of innovator health centers. Results : All health centers in the metropolitan cities of Seoul, Gwangju and Jeju adopted the HIS. The laggards were those in the metropolitan cities of Busan (18.8%), Incheon (20.0%) and Daejun (20.0%), and cities with population more than 300,000 (54.8%) and counties with health center hospitals (47.1%). Financially supported rural health centers adopted the HIS more rapidly than those not supported. The factors identified as being statistically significant (p<0.05), from a univariate analysis by Kaplan-Meier method, were: (1) internal factors of the type, size and innovativeness of health centers; (2) community factors of population size and economic status; (3) organizational environmental factors of the central government financial support and the neighborhoodness of innovator health centers. A multivariate analysis, using a Cox proportional hazard method, proved the innovativeness of health centers, central government financial support and the neighborhoodness of innovator health centers, were statistically significant (p<0.05). Conclusions : The innovativeness of health centers, financial support from central government and the neighborhoodness of innovator health centers, rather than community factors related to regional socioeconomic status, affected ffe adoption of the HIS in health centers. Further in-depth studies, modifying the MOHW's strategy to propagate the HIS to the laggard health confers, are recommended.