Hydrogenated Bisphenol-A type Epoxy Resin에 관한 연구

허정림,김성배 건국대학교 산업기술연구원 2000 건국기술연구논문지 Vol.25 No.-

In order to reduce and control the yellowing of a bisphenol-A type epoxy resin (BPA) available for powder coating, hydrogenated bisphenol-A epoxy resin (HPBA) was used. The specimens were prepared by powder coating of the epoxy resins on the steel plates. And their impact strength, flexural strength, gloss, weatherability, and chemical resistance were investigated by using various instrumnents such as Dupont and Erichsen testers. It was found that the mechanical properties of powder coated HBPA and BPA were almost the same. However, the results of weathering test showed that the weatherability of powder coated HBPA was significantly improved compared to that of powder coated BPA. From these results, it is expected that BPA resin can be replaced with HBPA resin in the various fields requiring high weatherability.

PS/EPR블렌드의 機械的 性質 및 Morphology에 關한 硏究

許正霖 建國大學校 附設 産業技術硏究所 1991 논문집 Vol.16 No.-

In recent years, rubber toughened plastics have drawn enormous attention because of their practical importance. Experimental study had been carried out on the morphological and mechanical aspects of PS/EPR blends employing SBR as a compatibilizer. Blended specimens were prepared through melt blending process using two-roll mill followed by compression molding step. The mechanical behavior of the blends was investigated in terms of tensile and impact strength, using Instron tensile tester at 18℃and impact tester at 0℃, respectively. Micro-structure of fratured surface of the impact specimens was observed utilizing a scanning electron microscope(SEM). It was found that the addition of the rubber increased the impact strength while it showed an adversary effect on the tensile strength of the specimens. It was also found that the average particle size of the rubber domain decreased with decreasing Mooney viscosity. PS/EPR/SBR blends showed very high dispersion of EPR phase in PS matrix compared to that of PS/EPR blends. The fine dispersion of the impact modifiers is a basic regulating factor of impact energy dissipation in the form of shear yielding and crazing.

피부로 전이된 방광암 1예

박정훈,김휘준,이무형,허충림 대한피부과학회 2003 大韓皮膚科學會誌 Vol.41 No.1

Metastasis to the skin from the urinary bladder carcinoma are very rare and their incidence is 1 % to 2% of the cutaneous metastasis. A 78-year-old man developed cutaneous metastasis 2 years later after the diagnosis of carcinoma of the bladder had been made. He visited our department with skin colored, soft, tender, subcutaneous nodule on the lower abdomen which had been detected 5 days ago. Histologic examination of the skin lesion showed atypical cells having hyperchromatic and pleomorphic nuclei. Herein we report a case of cutaneous metastasis from carcinoma of the urinary bladder in a 78-year-old man. (Korean J Dermatol 2003:41(1) : 133∼134)

Poly(ethylene oxide)/Poly(ε-caprolactone) 혼성체로부터 Bioactive Agent의 방출 거동에 관한 연구

유영태,허정림,정채열 건국대학교 1995 學術誌 Vol.39 No.2

Poly(ε-caprolactone)/poly(ε-caprolactone)-b-poly(ethylene oxide) hybrid membranes were used for the zeroth order release of lyophobic drug. Diffusivity of the drug increased with the copolymer content of the blend and the release rate was inversely proportional to the thickness of the membrane. The effective diffusivity of the drug was estimated as 1.07×10-3mm2/hr, 1.27×10-3mm2/hr and 1.83×10-3mm2/hr for the membranes containing 37.5wt% of PCL-PEO-PCL block copolymers with compositions of 20k-20k-20k, 15k-15k-15k and 6k-6k-6k, respectively.

폴리프로필렌 이형단면사 제조에서 방사조건이 이형도에 미치는 영향

윤문구,허정림,서문호 건국대학교 1997 學術誌 Vol.41 No.2

The influence of spanning condition on the shape factor of polypropylene profiled yarn was studied experimentally. Test spinning of polypropylene was carried out by utilizing a Y-shaped capillary die which has been designed to produce profited yarn. The types, of spring machine used for this study were both conventional undrawn yarn spinning and one-step spin-draw machine. From the experimental results, there was little differences in the shape factor between undrawn and drawn yarns. The shape of the yarn was mainly determined in the spinning process. Also, the shape factor of the drawn yarn produced from the spin- draw machine was greater than that of by conventional spinning and drawing two- step process. Anisotropy of surface tension in cross section of extrudates was responsible for the resulting shape factor. As the output rate and the fineness of yarn Increased, its shape factor decreased.

EP 고무로 개질한 Nylon-6의 유변학적 성질

Haw, Jung-Rim,Lee, Sung,Kim, Byeong-Cheol,Lee, Dai-Soo 한국유변학회 1993 Korea-Australia rheology journal Vol.5 No.2

Nylon-6의 내충격성을 개선하기 위한 개질제로써 에틸렌-프로필렌 고무(EPR)와 에 틸렌-아크릴 에스터-무수말레산 공중합체(EAM)를 첨가한 nylon-6/EPR/EAM 블렌드 시스 템의 유변학적 특성을 24$0^{\circ}C$에서 조사하였다. 개질제중 EAM의 점도는 조성물 가운데 가장 낮음에도 불구하고 첨가량을 증가함에 따라 블렌드의 점도는 증가하였다. 또한 EPR(I)의 점 도가 EPR(II)의 점도보다 낮지만 EAM 함량이 증가함에 따라 nylon-6/EPR(I)/EAM의 점도 는 nylon-6/EPR(II)/EAM의 점도보다 높아지는 현상이 관찰되었다. 이러한 특성을 분산상의 morphology 변화와 전단력하에서 변형이 어려워지기 때문인 것으로 해석하였다.

Blends of Nylon -6 and Ehtylene - Propylene Rubber Prepared by Malt Mixing with Maleic Anhydride

Haw, Jung Rim,Lee, Dai Soo,Chung, Bong Woo,Kim, Byeongcheol,Lee, Sung 한국공업화학회 1995 Journal of Industrial and Engineering Chemistry Vol.1 No.1

There have been many studies on toughening of polyamide with maleated ethylene-propylene rubber (MEPR) which forms graft copolymer with polyamide by reactions between maleic anhydride of MEPR and amine group of polyamide during melt mixing. Previous studies showed that the graft copolymers formed in situ during melt mixing reduced the size of rubber particles in polyamide/MEPR blends and effectively improved the toughness of polyamide. In this paper, structure-property relationships of Nylon-6 and ethylene-propylene rubber(EPR) blends prepared by melt mixing of Nylon-6, EPR, maleic anhydride(MAH), and dicumyl peroxide(DCP) are investigated. It was observed that the size of rubber particles in the Nylon-6/EPR blends decreased as the MAH content increased in the blends. In Molau test, formation of graft copolymers in the Nylon-6/EPR blends was confirmed. The tensile strength and melt viscosity of the blends increased and leveled off as the MAH content increased. The notched Izod impact strength showed brittle-tough transition as the MAH contents increased from 0.1 to 0.2 parts per hundred of the blends. It was postulated that melt mixing of Nylon-6, EPR, MAH, and DCP in one step is an effective way of preparing tough Nylon-6/EPR blends like Nylon-6/MEPR blends.

에틸렌 - 프로필렌 고무와 에틸렌 - 아크릴에스터 - 무수말레산 공중합체로 개질한 Nylon -6 의 구조와 물성

허정림(Jung Rim Haw),이성(Sung Lee),이대수(Dai Soo Lee) 한국고분자학회 1993 폴리머 Vol.17 No.6

에틸렌의 촉매 산화에 의한 산화 에틸렌의 제조

허정림,이현구,나상천 한국화학공학회 1978 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.16 No.2

α-알루미나를 담체로 하여 함침법으로 은촉매를 제조하고, 공기를 산화제로 에틸렌을 산화하여 산화에틸렌을 제조하였다. 연속식 반응장치를 이용하여 여러가지 반응조건에서 에틸렌의 전환률과 산화에틸렌으로의 선택도를 측정하였다. 촉매로는 20∼40 mesh의 분발형 촉매와 직경이 1/4 inch 되는 입자형 촉매를 각각 사용하였다. 이들 촉매의 선택도는 60∼70%에 달하였으며 입자형 촉매가 분말형 촉매에 비하여 더 높은 선택도를 나타내었다. 산화에틸렌의 생성속도는 반응온도가 230℃, 반응혼합물중 에틸렌의 함량이 7.2mole%, 또 반응혼합물의 공급유량이 300 ㎖/min 일 때, 1.2×10^(-3)mole/hr-gm catalyst로 제일 높았다. 조촉매로서 바륨이 첨가되었을 때, 촉매의 선택도는 어느 정도 개선되었으나 에틸렌의 전환률이 저하되는 경향을 나타내었다. 한편 촉매입자의 내부에 은과 바륨이 분산되어 있는 상처를 금속현미경으로 관찰하여 검토하였다. Silver catalyst was prepared with α-alumina support by the impregnation method and used to produce ethylene oxide by oxidation of ethylene with air. A continuous flow reactor system was set up to investigate the activity as well as the selectivity of the catalyst under various reaction conditions. Both the catalyst in powder form (20-40 mesh) and that in pellet form (1/4 in. in diameter) were tested. While both catalysts obtained a selectivity ranging from 60 to 70%, the catalyst in pellet form exhibited a better performance. Within the range of experimental conditions, the production rate of ethylene oxide reached the highest value, 1.2×10^(-3) mole/hr-gm catalyst, when the reaction mixture containing 7.2 mole% ethylene was supplied at a rate of 300 ㎖/min and the reaction temperature was maintained at 230℃. Barium added as a promoter improved the selectivity to some extent, although there resulted in a significant decrease in the total conversion of ethylene. Dispersions of silver and barium inside the catalyst particle were examined by utilizing a metallurgical microscope.

Erythema Dyschromicum Perstans 3예

정영철,임수덕,윤재일,허충림,한을남 대한피부과학회 1982 大韓皮膚科學會誌 Vol.20 No.6

We observed three patients who showed widespread macular ashy-colored eruptions. They fit clinically and histopathologically with the typical erythema dyschromicum perstans (ashy dermatosis). Erythoma dyschromicum perstans is a peculiar pigmented condition of unknown etiology characterized by persistent ashy-gray colored macule, refractory to any modality. All of them have similar skin lesions which are multiple, variable sized oval-shaped, ash-colored macular eruption on the trunk and extremities. Histologic findings of 2 patients reveal the characteristic feature of focal hydropic degeneration of the basal cell layer of the epidermis, perivascular infiltrates of lymphocytes and histiocytes and melanin-laden macrophages in the corium, however, merely pigmentary incontinence into the corium in 1 patient. Literatures are briefly reviewed.