• Journal of the Korean Applied Science and Technology
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• v.25 no.4
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• pp.525-532
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• 2008

To prepare a solution type acrylic pressure-sensitive adhesive, quarter polymers were synthesized from butyl acrylate(BA), 2-ethylhexylacrylate(2-EHA) as a base monomer, methyl methacrylate(MMA) as a comonomer, each of methacrylic acid(MAA), acrylic acid(AA) as a functional monomer. Acrylic solution type pressure-sensitive adhesives(PSA's) of isocyanate derivative crosslinking PSA's were prepared by crosslinking of BEMM, BEMA with toluene-2,4-diisocyanate. The structure of adhesive was identified by FT-IR. The viscosity was measured by using Brookfield DV-III and molecular weight was measured by using gel permeation chromatography. The physical properties of polyethylene film coated with BEMMT, BEMAT were measured as a function of the concentration. As the result, BEMMT(0.6, 0.8), BEMAT(0.6) showed peel adhesion of $160{\sim}180\;g_f$/25 mm width and shear adhesion of more than 24 hours, and tackiness of $4/32{\sim}6/32$ which was relevant to commercial usage.

• Environmental Analysis Health and Toxicology
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• v.23 no.2
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• pp.113-117
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• 2008

Biomonitoring of nonylphenol (NP), an endocrine disrupting chemical, is required in Korea to perform its proper regulation. Thus, we analyzed exposure levels of nonlyphenol (NP) in breast milk from the mothers who delivered babies within 10 days (N=325). We analyzed free and total forms of NP in breast milk with LC/MS/MS (LOD, 0.5 ppb). In addition, we obtained questionnaires concerning lifestyle from the subject. As results, ranges of total NP were ${\mu}g/L$ (median, $3.51{\pm}4.98{\mu}g/L$ vs. normal, N=281, $2.07{\pm}3.76{\mu}g/L$; p<0.05). In conclusion, we suggest that exposure monitoring of NP should be continuously performed, even though the risks of NP are not clear, yet.

• Journal of Preventive Medicine and Public Health
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• v.29 no.1 s.52
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• pp.103-112
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• 1996

We studied the association of nonspecific bronchial hyperresponsiveness with general characteristics, exposure concentration, respiratory symptoms, chest x-ray findings, past histories and pulmonary function. We determined bronchial hyperresponsiveness by methacholine challenge test. And we conducted a respiratory symptom questionnaire and performed spirometry on 111 workers occupationally exposed to isocyanates in various industries. About 21.6% of subjects had bronchial hyperresponsiveness. No significant differences were observed between the hyperresponsive and non-responsive group with respect to age, sex, employment period, height, and smoking histories. Cough and breathlessness were significantly associated with the bronchial hyperresponsiveness. The hyperresponsive group had more experience of bronchitis and asthma in the past than the non-responsive group. The lower $FEV_1\;and\;FEV_1%$ were closely related with bronchial hyperresponsiveness. Bronchial hyperresponsiveness seems to be associated with some of respiratory symptoms, past histories and pulmonary function parameters in workers exposed to isocyanates.

• Korean Membrane Journal
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• v.1 no.1
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• pp.81-85
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• 1999

Tributyl phyosphate(TBP) polypropylene glycol 4000(PPG-4000) and the mixture of two compounds were examined as a liquid membrane in a supported liquid membrane (SLM) to separate phenol from aqueous solution.The feed concentration of phenol was varied in a broad range from 500 mg/L to 5000 mg/L and different types of liquid membrane were prepared to elucidate their effects on separation of phenol. It was found that the modified PPG 4000 with TBP and toluene diisocyanate(TDI) might be used as a proper liquid membrane because the mass transfer rate examined with this membrane was higher than that through methyl isobutyl ketone (MIBK) which has been used as a conventional solvent in a solvent extraction process. The breakthrough pressure of the SLM is defined to be the pressure difference across the membrane at which the supported liquid membrane is not kept in the pores any more. it indicates how the SLM is stable., It was found that the breakthrough pressure of the modified PPG-4000 was much higher than those of typical organic solvents.

• Journal of the Korean Applied Science and Technology
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• v.20 no.2
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• pp.87-93
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• 2003

Two-component polyurethane flame retardant coatings (ATTBC) were prepared by blending polyisocyanate (TDI-adduct) with ATTBs mentioned at the previous paper. Most of the physical properties of the flame retardant coatings were comparable to those of non-flame retardant coatings. Especially, the hardness, impact resistance, and accelerated weathering resistance were remarkably improved with the increase of the content of 1,4-butanediol. Coatings containing 10 and 15 wt% 1,4-butanediol, ATTBC-10C and ATTBC-15C, were not flammable in vertical flame-retardancy test. Their char area recorded 1.1${\sim}$11.6 $cm^2$ in 45$^{\circ}$ eckel burner method.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.81-85
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• 2003

PU block polymers are constituted by sequences of constitutional units CU which are : a diisocyanate T, a polyol or a polyamine V, an extensor E .Due to the CU different solubility parameters ,hard and soft micro domains are formed;they can aggregate into different phases. A linear PU can be described by two parameters R=T/N and $R_{E}$=(R-1)V/E.A stoichiometric model is proposed which gives the general formula of all the possible PU: X((TV)$_{k}$(TE)$_{n}$)$_{m}$X , where k and m can be calculated from the experimental molecular weights respectively of pre polymer and polymer and n= R-1.Physical properties depend on PU composition and on nature of CU. I.R. analysis is useful for discovering the hydrogen bonds location : DSC gives informations on the presence of the different phases .PALS analysis shows that nano cavities become tighter on increasing n. A series of particular Pus ,obtained from :TDI, a low molecular weight polyol, a cyclic extensor, at different R and RE was prepared and analysed. These PU are amorphous, monophasic and appear to be good candidates for membranes.nes.nes.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.3
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• pp.209-216
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• 2012

Objectives: Polyurethanes are usually formed by the reactions of liquid diisocyanate components with liquid polyol resin components. Although polyurethanes have advantageous properties, such as their versatility, the manufacturing process generates diisocyanates, which can cause asthma and respiratory irritation in exposed workers. This study compared the differences in diisocyante concentrations between two different (molded foam and slabstock foam) polyurethane foam manufacturing methods. Materials and Methods: Active samples and direct reading samples of diisocyanates (MDI, TDI) were collected in five polyurethane foam manufacturing companies. Results: Workers' exposure concentrations of diisocyanate (GM: 4.078 ppb, range: 1.190~23.770 ppb) in a slabstock foam manufacturing company were much higher than those (GM: 0.011 ppb, range: 0.001~0.055 ppb) in molded foam manufacturing companies. The results of the direct reading samples of diisocyanate indicated that the rapid reaction zone of the slabstock foam processes emitted large amounts of diisocyanates. Conclusions: The exposure levels of diisocyanates for all molded foam workers were much lower than the occupational exposure standard (5 ppb); however, exposure levels for many slabstock foam workers exceeded the standard.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.648-653
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• 1998

This study examines the effects of cell size and structure on the oil adsorption by polyurethane (PU) foam. A series of oil-adsorptive PU foam has been prepared, using various molecular weight of polyether polyol (GP-1000, GP-3000, GP-4000, GP-5000), together with TDI-80, water and additives. It was found that the cell size of PU foam decreased with increasing the agitation speed and surfactant content. Oil-adsotption of PU foam increased over 2000% with the increase of molecular weight of polyol and with the decrease of cell size. Increase in the surfactant content and the viscosity of adsorbed oil also give a remarkable decrease in oil adsorption.

• Journal of Trauma and Injury
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• v.32 no.1
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• pp.66-70
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• 2019

Traumatic diaphragmatic injuries (TDIs) are a rare complication in thoraco-abdominal trauma. The diagnosis is difficult and if left untreated, TDI can cause traumatic diaphragmatic hernia (TDH). Through an injured diaphragm, the liver, spleen, stomach, small intestine, and large intestine can be herniated to the thoracic cavity, but pancreatic herniation and pancreatitis are quite rare in TDH. This paper reports a case of pancreatitis developed by additional trauma in a patient with asymptomatic chronic TDH. A 58-year-old male visited the emergency department with a left abdominal injury after a fall 6 hours earlier. The vital signs were stable, but the amylase and lipase levels were elevated to 558 U/L and 1,664 U/L, respectively. Abdominal computed tomography (CT) revealed a left diaphragmatic hernia and an incarceration of the stomach, pancreatic ductal dilatation, and peripancreatic fatty infiltration. Additional history taking showed that he had suffered a fall approximately 20 years ago and had an accidentally diaphragmatic hernia through a chest CT 6 months earlier. A comparison with the previous CT revealed the pancreatitis to be caused by secondary pancreatic ductal obstruction due to the incarcerated stomach. For pancreatitis, gastrointestinal decompression was performed, and after 3 days, the pancreatic enzyme was normalized; hence, a thoracotomy was performed. A small ruptured diaphragm was found and reposition of the organs was performed. This paper reports the experience of successfully treating pancreatitis and pancreatic hernia developed after trauma without complications through a thoracotomy following gastrointestinal decompression.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.152-152
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• 2023

하천의 건강성을 평가하기 위해 일반적으로 수생태계 건강성 지표(TDI, BMI, FAI, HRI, RVI)가 사용되고 있다. 이 지표는 5가지 등급으로 구분하여 매우 좋음(A), 좋음(B), 보통(C), 나쁨(D), 매우나쁨(E)으로 구분된다. 하지만, 하천의 건강성 관점에서 수질, 토지이용, 지리적 특성, 경관지수와의 상관성을 바탕으로 어떤 영향을 미치는지에 대한 연구가 필요하다. 본 연구에서는 하천의 수생태계 건강성에 영향을 미치는 환경적 인자들과의 관계성을 분석하여 수생태계 건강성이 '좋음'에 해당되는 하천으로 분류하고자 한다. 이를 통해 환경적 인자들의 임계값을 산출하여 하천 관리에 대한 구체적인 우선순위 설정 방안을 제안하고자 한다. 낙동강대권역을 대상으로 수질, 토지이용, 지리적 특성, 경관지수의 여러 변수 중 수생태계 건강성과의 관계에서 대표성을 나타낼 수 있는 환경적 인자를 선정하기 위하여 정준상관분석(CCA)을 수행하였다. 또한 모델 기반의 클러스터 분석을 활용하여 소권역별로 수생태계 건강성이 '좋음'에 해당할 확률을 파악하고, 여기에 해당하는 소권역에 대하여 각각의 환경적 인자에 대한 임계값을 정량적으로 평가하였다. 본 연구에서는 하천의 환경 인자들과의 관계를 분석하여 수생태계 건강성을 평가하고 하천 관리에 대한 구체적인 우선순위를 파악하는 방법을 제안한다. 주성분 분석 및 모델 기반 클러스터 분석을 사용하여 각 소권역에 대한 환경 인자의 임계값을 평가하고, 정책 결정자들이 하천의 건강성을 유지하고 개선할 수 있는 정보를 제공할 수 있다.