• Toxicological Research
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• 제25권2호
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• pp.85-92
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• 2009

4,4'-Methylenedianiline (MDA) is an aromatic amine that is widely used in the industrial synthetic process. Genotoxic MDA forms DNA adducts in the liver and is known to induce liver damage in human and rats. To elucidate the molecular mechanisms associated with MDA-induced hepatotoxicity, we have identified genes differentially expressed by microarray approach. BALB/c male mice were treated once daily with MDA (20 mg/kg) up to 7 days via intraperitoneal injection (i.p.) and hepatic damages were revealed by histopathological observation and elevation of serum marker enzymes such as AST, ALT, ALP, cholesterol, DBIL, and TBIL. Microarray analysis showed that 952 genes were differentially expressed in the liver of MDA-treated mice and their biological functions and canonical pathways were further analyzed using Ingenuity Pathways Analysis (IPA). Toxicological functional analysis showed that genes related to hepatotoxicity such hyperplasia/hyperproliferation (Timp1), necrosis/cell death (Cd14, Mt1f, Timp1, and Pmaip1), hemorrhaging (Mt1f), cholestasis (Akr1c3, Hpx, and Slc10a2), and inflammation (Cd14 and Hpx) were differentially expressed in MDA-treated group. This gene expression profiling should be useful for elucidating the genetic events associated with aromatic amine-induced hepatotoxicity and for discovering the potential biomarkers for hepatotoxicity.

• 한국환경보건학회지
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• 제49권6호
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• pp.334-343
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• 2023

Background: South Korea's Act on Registration and Evaluation, etc. of Chemicals (known as K-REACH) was established to protect public health and the environment from hazardous chemicals. 4,4'-Methylenedianiline (MDA), which is used as a major intermediate in industrial polymer production and as a vulcanizing agent in South Korea, is classified as a toxic substance under the K-REACH act. Although MDA poses potential ecological risks due to industrial emissions and hazards to aquatic ecosystems, no ecological risk assessment has been conducted. Objectives: The aim of this study is to assess the ecological risk of MDA by identifying the actual exposure status based on the K-REACH act. Methods: Various toxicity data were collected to establish predicted no effect concentrations (PNECs) for water, sediment, and soil. Using the SimpleBox Korea v2.0 model with domestic release statistical data and EU emission factors, predicted environmental concentrations (PECs) were derived for ten sites, each referring to an MDA-using company. Hazard quotient (HQ) was calculated by ratio of the PECs and PNECs to characterize the ecological risk posed by MDA. To validate the results of modeling-based assessment, concentration of MDA was measured using in-site freshwater samples (two to three samples per site). Results: PNECs for water, sediment, and soil were 0.000525 mg/L, 4.36 mg/kg dw, and 0.1 mg/kg dw, respectively. HQ for surface water and sediment at several company sites exceeded 1 due to modeling data showing markedly high PEC in each environmental compartment. However, in the results of validation using in-site surface water samples, MDA was not detected. Conclusions: Through an ecological risk assessment conducted in accordance with the K-REACH act, the risk level of MDA emitted into the environmental compartments in South Korea was found to be low.

• 분석과학
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• 제25권4호
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• pp.236-241
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• 2012

낙동강 수계는 중 상류 지역에 대규모 공단이 입지하고 있어 그동안 phenol, 1,4-dioxane, perchlorate 등 유해물질에 의한 수질오염사고가 많이 발생하였다. 본 연구에서는 낙동강 수계에 유출 가능성이 있는 미규제 유해물질 중 반휘발성유기화합물질(semi-volatile organic compoumsds, SVOCs) 10종(dichlorvos, toluene-2,4-diisocyanate, 4,4'-methylenedianiline, 4,4'-methylenebis(2-chloroaniline), diethyl phthalate, di-n-butyl phthalate, butyl benzyl phthaltate, bis(2-ethylhexyl)adipate, benzophenone, 4,4'-bisphenol A)에 대하여 디스크형 고상 추출법과 GC/MS를 이용하여 분석하였으며, 정확도 75.6~110.5%, 정밀도 4.6~12.7%, 회수율 72.4~127.9%의 결과를 얻을 수 있었다. 낙동강 수계에 위치한 하 폐수처리장 및 폐수배출업소 등 공장폐수 시료를 분석한 결과 bis (2-ethylhexyl)adipate, benzophenone, 4,4'-bisphenol A 등 3개 물질이 검출되었다.

• 멤브레인
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• 제25권4호
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• pp.343-351
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• 2015

본 연구에서는 높은 기체선택도를 가지는 폴리이미드의 제조를 위해 2,2-bis(3,4-carboxylphenyl) hexafluoropropane과 두 종류의 아민인 2,4,6-Trimethyl-1,3-phenylenediamine (DAM)과 4,4-Methylenedianiline (p-MDA)을 이용하여 합성을 진행한 후 비용매 상전이법으로 비대칭 분리막을 제조하였다. 분리막 제조에 사용된 용매에 따른 물성변화를 확인하기 위하여 고분자 용액의 점도, 흐림점 측정을 통한 고분자의 상평형도, 비용매 상전이 계수 측정을 진행하였다. 상전이법을 이용하여 제조된 분리막은 SEM을 통해 용매 휘발시간에 변화에 따른 모폴로지를 확인하였고 이의 변화에 따른 기체 투과도 변화를 확인하였다. 기체투과도는 디메틸아세트아마이드를 사용하였을 때보다 N-메틸-2-피롤리돈을 사용하였을 때 $CH_4$, $N_2$, $O_2$, $CO_2$의 투과도와 각 기체에 대한 선택도가 높은 것을 확인하였다. 또한 용매 휘발 시간이 길수록 기체 투과도는 감소하지만 기체에 대한 선택도가 증가하는 것을 확인하였다.

• 멤브레인
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• 제25권3호
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• pp.223-230
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• 2015

새로운 구조를 가진 공중합체 폴리이미드를 이용하여 고투과, 고선택성 기체 분리막을 제조하였다. 기체투과도와 용해도를 높이기 위해 무수물인 2,2-bis(3,4-carboxylphenyl) hexafluoropropane과 두 종류의 아민인 2,4,6-Trimethyl-1,3-phenylenediamine과 4,4-Methylenedianiline을 사용하여 신규 폴리이미드를 합성하였다. Triethylamine과 Acetic anhydride를 사용하여 화학적 이미드화 방법으로 공중합체를 합성하였으며, 평균분자량은 100,000 g/mol 이상을 나타내었다. 합성된 고분자의 열적 특성을 분석을 하기 위해 시차주사열량계(DSC)와 열중량분석기(TGA)로 측정을 하였으며, 유리전이온도(Tg)는 $300^{\circ}C$, 열분해 온도는 $500^{\circ}C$가 넘는 뛰어난 내열성을 나타내었다. 기체투과도 특성은 time-lag 장비를 사용하였으며 그 결과, 일반적인 폴리이미드의 경우 대부분 기체투과도가 1 barrer 이하의 수치를 보이지만, 합성된 고분자의 경우 산소투과도 10.10 barrer과 산소/질소 선택도의 경우 5.3으로 고투과, 고선택도를 나타내어 기체 분리막 분야에 적용 가능성을 확인할 수 있었다. 합성된 고분자 중 기체투과특성이 더 우수한 공중합 폴리이미드를 사용하여 중공사를 제조하였고, 이를 이용하여 기체투과특성을 측정하였다.

• Elastomers and Composites
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• 제51권2호
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• pp.122-127
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• 2016

Thermal decomposition kinetics for two different types of polyurethane elastomers prepared with 2,2'-dichloro-4,4'-methylenedianiline (MOCA) and 3,5-dimethyl-thiotoluenediamine (Ethacure-300), based on PTMG/TDI isocyanate prepolymer, were studied using non-isothermal thermogravimetric analysis (TGA). Thermograms were obtained and analyzed using Friedman (FR) and Kissinger-Akahira-Sunose (KAS) methods for activation energy, $E_a$. The results obtained showed that decomposition reaction of both samples was observed similarly to occur through three different stages, i.e., initial stage with vaporization of low molecular weight materials, second stage of urethane linkage decompositions, and later stage of polyol segment decompositions. However, activation energy values at each stage for the sample cured with Ethacure-300 was much lower than those for the sample with MOCA, exhibiting relatively lower thermal stability for the sample with Ethacure-300 than that with MOCA.

• Elastomers and Composites
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• 제53권2호
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• pp.52-56
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• 2018

The present study examines the transformation of dynamic DSC data into the equivalent isothermal data for the formation kinetics of a polyurethane elastomer. The reaction of 2'-dichloro-4,4'-methylenedianiline (MOCA) with a PTMG/TDI-based isocyanate prepolymer was evaluated. DSC measurement was performed in the dynamic scanning mode with several different heating rates to obtain the reaction thermograms. Then, the data was transformed into the isothermal data through a procedure based on Ozawa analysis. The main feature of this procedure was the transformation of $({\alpha}-T)_{\beta}$ curves from dynamic DSC into $({\alpha}-t)_T$ curves using the isoconversional $(t-T)_{\alpha}$ diagram. Validity was discussed for the relationship between the dynamic DSC data and the transformed isothermal results.

• 한국재료학회지
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• 제11권9호
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• pp.786-791
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• 2001

$\alpha$,$\omega$-Bis(4-glycidyloxybenzylidene-4-aminophenyl)methane (BGBAM) was synthesized from the initial materials, 4-hydroxylbenzaldehyde (HBA), 4,4'-methylenedianiline (MDA) and epichlorohydrin. The DSC trace for BGBAM shows two endotherms associated with the liquid crystalline phase transition around $104.2^{\circ}C$ and the isotropic transition around $171.2^{\circ}C$, and it also has a broad exotherm in the range of $178~300^{\circ}C$ due to the anionic homopolymerization of BGBAM. DSC curve for the curing of BGBAM with hexamethylene diamine (HMD) shows an endothermic peak around $93^{\circ}C$ attributed to the melting of BGBAM. It also has three exothermic peaks around $128.4^{\circ}C$ and $180.2^{\circ}C$ associated with the epoxide-amine reaction and weak peak in the range of $200~263^{\circ}C$ related to the anionic homopolymerization between the unreacted epoxide groups. The activation energy values of cure reaction by Kissinger method are 66.5, 67.3 and 90.6 kJ/mol for $T_{pl},\; T_{p2}\; and \;T_{p3},\; respectively$. The kinetic parameters by isoconverional method are similar value to those from Kissinger method.

• 한국산업보건학회지
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• 제26권2호
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• pp.178-187
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• 2016

Objectives: Diisocyanates are a potent inducer of diseases of the airways, especially asthma. In this study, toluenediamine(TDA) and methylenedianiline(MDA) in urine were evaluated as biomarkers of exposure to tolunenediisocyanate(TDI) and methylenediphenyl diisocyanate(MDI), respectively. Methods: Workers exposed to TDI and MDI, as well as non-occupationally exposed subjects, were studied and pre- and post-shift urine samples were collected from 8 control subjects and 8 workers from a factory which manufactures polyurethane products for reducing noise and vibration in automobiles. Airborne TDI and MDI(n=8) were sampled on solvent-free glass filters impregnated with n-butylamine and detected by liquid chromatography atmospheric pressure ionization tandem mass spectrometry. Urinary TDA and MDA were detected as pentafluoropropionic acid anhydride(PFPA) derivatives by liquid chromatography electrospray ionization tandem mass spectrometry. Results: The median levels of urinary 2,6-TDA(p<0.001), 2,4-TDA(p=0.001), and MDA(p<0.001) of workers in post-shift samples were significantly higher than those of controls. The median levels of urinary 2,6-0TDA($0.63{\mu}g/g$ creatinine vs $0.34{\mu}g/g$ creatinine, p=0.017) and MDA($4.21{\mu}g/g$ creatinine vs $3.18{\mu}g/g$ creatinine, p=0.017) of workers in post-shift samples were significantly higher than those of the pre-shift samples. There were significant correlations between the urinary 2,6-TDA, 2,4-TDA, and MDA of workers in post-shift samples and the airborne 2,6-TDI(rho=0.952, p<0.001), 2,4-TDI(rho=0.833, p=0.001), and MDI(rho=0.952, p<0.001). Conclusions: These urinary diamines, metabolites of diisocyanates, in post-shift samples were useful biomarkers to assess occupational exposure to diisocyanates.

• Elastomers and Composites
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• 제50권2호
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• pp.92-97
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• 2015

A study on reaction kinetics for a PTMG/TDI prepolymer with 2,2'-dichloro-4,4'-methylenedianiline (MOCA), of which formulations may be generally used for fabricating high performance polyurethane elastomers, was peformed using non-isothermal differential scanning calorimetry (DSC). A number of thermograms were obtained at several constant heating rates, and analysed using Flynn-Wall-Ozawa (FWO) isoconversional method for activation energy, $E_a$ and extended-Avrami equation for reaction order, n. Urea formation reaction of the present system was observed to occur through the simple exothermic reaction process in the temperature range of $100{\sim}130^{\circ}C$ for the heating rate of $3{\sim}7^{\circ}C/min$. and could be well-fitted with generalized sigmoid function. Though activation energy was nearly constant as $53.0{\pm}0.5kJ/mol$, it tended to increase a little at initial stage, but it decreases at later stage by the transformation into diffusion-controlled reaction due to the increased viscosity. Reaction order was evaluated as about 2.8, which was somewhat higher than the generally well-known $2^{nd}$ order values for the various urea reactions. Both the reaction order and reaction rate explicitly increased with temperature, which was considered as the indication of occurring the side reactions such as allophanate or biuret formation.