• Journal of the Korean Applied Science and Technology
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• v.29 no.2
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• pp.224-230
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• 2012

In this paper, flame-resisting PMMA(polymethyl methacrylate) sheet was manufactured and its characteristics were tested. PMMA was synthesized by bulk polymerization of a monomer methyl methacrylate with addition of phosphorous flame retardant, triethyl phosphate and ethylene glycol dimethacrylate as a cross linking agent. PMMA sheet was manufactured by using the cell molding method, which does not alter or affect the existing property of PMMA. Then the characteristics of PMMA sheet were tested for the TEP content, the content and curing time of EGDMA. As TEP content increases, the length of carbonization lessens and the amount of char production increases. As a result, it strengthened the effect of flame retardants. But the hardness of the sheet decreased as TEP content increased. However, hardness increased when EGDMA was added up to 3 wt% while curing time was decreased from 3 hours to 2 hours. There was no change of hardness when more than 3 wt% of EGDMA was used.

• Elastomers and Composites
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• v.38 no.3
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• pp.251-261
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• 2003

The flame retardancy and foaming properties of NBR foams containing waste ground tire rubber (GTR) were studied. When the composition ratios of NBR/GTR were ranged in $100/0{\sim}80/20$ (w/w) and rubbers/flame retardants were in the range of $1/1.95{\sim}3.70 wt%$, the considerably optimized foam for flame retardancy was obtained with high limiting oxygen indices (LOI, $29.4{\sim}40.0$), low heat release rate(HRR), closed/semi-closed cell of uniformity, and reasonable expandability ($215{\sim}300 %$). The LOI was increased and the heat release rate was decreased with increasing the amount of GTR content.

• Journal of the Korea Institute of Building Construction
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• v.13 no.2
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• pp.122-130
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• 2013

One of recent methods to protect wooden cultural assets from fire, there is the flame retardation which is applied directly to wood and it is to prevent fire through securing flame resistance for the material and delaying combustion when failed fire in advance and then to gain time for people in the room to evacuate and it has same goal with the Korean Fire Service Act by protecting life and property. However, in case of spraying flame retardant on the colored surface of the wooden cultural assets, there are continuous problems of decoloration, efflorescence and water absorbtion after sometime and accordingly there increases danger of damages of cultural assets. So when treating with flame retardant on wooden cultural assets, there has to be no problems on dancheong after sometime and securing sustainable methods for flmae retardation should be preceded. Accordingly, this study aims to provide basic sources for selecting proper flame retardation methods by evaluating and analyzing flame retardation capabilities according to types of flame retardants which are frequently used nowadays and spraying them on the dancheong-painted surface and confirming if there is no problem on the dancheong and wood after sometime and if flame retardation effect is sustainable with its quality and capability through precise analysis.

• Toxicological Research
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• v.27 no.2
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• pp.61-70
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• 2011

Brominated flame retardants (BFRs) are present in many consumer products ranging from fabrics to plastics and electronics. Wide use of flame retardants can pose an environmental hazard, which makes it important to determine the mechanism of their toxicity. In the present study, dose-dependent toxicity of tetrabromobisphenol A (TBBPA), a flame retardant, was examined in male prepubertal rats (postnatal day 18) treated orally with TBBPA at 0, 125, 250 or 500 mg/kg for 30 days. There were no differences in body weight gain between the control and TBBPA-treated groups. However, absolute and relative liver weights were significantly increased in high dose of TBBPA-treated groups. TBBPA treatment led to significant induction of CYP2B1 and constitutive androstane receptor (CAR) expression in the liver. In addition, serum thyroxin (T4) concentration was significantly reduced in the TBBPA treated group. These results indicate that repeated exposure to TBBPA induces drug-metabolising enzymes in rats through the CAR signaling pathway. In particular, TBBPA efficiently produced reactive oxygen species (ROS) through CYP2B1 induction in rats. We measured 8-hydroxy-2'-deoxyguanosine (8-OHdG), a biomarker of DNA oxidative damage, in the kidney, liver and testes of rats following TBBPA treatment. As expected, TBBPA strongly induced the production of 8-OHdG in the testis and kidney. These observations suggest that TBBPA-induced target organ toxicity may be due to ROS produced by metabolism of TBBPA in Sprague-Dawley rats.

• Elastomers and Composites
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• v.45 no.2
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• pp.87-93
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• 2010

The fire resistive materials are used to resist from fire accidents in the building. In this study silicone rubber/inorganic flame retardant composites were prepared by mechanical stirring method, using aluminium trihydroxide(ATH, $Al(OH)_3$) and magnesium dihydroxide(MDH, $Mg(OH)_2$) as synergistic fire-resistant additives. The thermal properties of the fire resistant composites were characterized by thermogravimetric analysis(TGA). In addition, rheological properties were observed by rheometer and fire-resistant properties were tested by gas torch. Through this study, we realized that the silicone rubber containing ATH, MDH increased the performance of fire-resistance.

• Journal of the Korean Society of Safety
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• v.26 no.4
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• pp.47-58
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• 2011

Halogen free intumescent flame retardants(IFRS), such as the mixture of melamine phosphate(MP) and char forming agents(pentaerythritol(PER), di-pentaerythritol(DiPER), tris(2-hydroxyethyl) isocyanurate(THEIC)), were prepared and characterized. Polypropylene(PP)/$IFR_S$ composites were also prepared in the presence of ethylene diamine phosphate(EDAP) as a synergist and used into flame retardant PP powder coatings. Thermoplastic PP powder coatings at 20 wt% flame retardant loading were manufactured by extruded and then mechanical cryogenic crushed to bring them in fine powder form. These intumescent flame retardant powder coatings($IFRPC_S$) were applied on mild steel surface for the purpose of protection and decorative. It is a process in which a $IFRPC_S$ particles coming in contact with the preheated mild steel surface melt and form a thin coating layer. The obtained MP flame retardant was analyzed by utilizing FTIR, solid-state $^{31}P$ NMR, ICP, EA and PSA. The mechanical properties as tensile strength, melt flow index(MFI) and the thermal property as TGA/DTA and the fire safety characteristics as limiting oxygen index(LOI), UL94 test, SEM were used to investigate the effect of $IFRPC_S$. The experimental results show that the presence of $IFR_S$ considerably enhanced the fire retardant performances as evidenced by the increase of LOI values 17.3 vol% and 32.6 vol% for original PP and $IFRPC_S$-3(PP/MP-DiPER/EDAP), respectively, and a reduction in total flaming combustion time(under 15 sec) in UL94 test of $IFRPC_S$. The prepared $IFRPC_S$-3 have good comprehensive properties with fire retardancy 3.2 mm UL94 V-0 level, LOI value 32.6%, tensile strength $247.3kg/cm^2$, surface roughness Ra $0.78{\mu}m$, showing a better application prospect. Through $IFRPC_S$-2(PP/MP-PER/EDAP) and $IFRPC_S$-3 a better flame retardancy than that of the $IFRPC_S$-1(PP/MP/EDAP) was investigated which was responsible for the formed more dense and compact char layer, improved synergy effect of MP and PER/DiPER.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1996.11a
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• pp.62-67
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• 1996

The smouldering combustion of cellulose Insulation treated with boric acid - borax - aluminium sulfate as combustion retardants are examined by candle type combustibility tester. The flammability behavior of combustion process is LOI, Smouldering region, Smouldering, Flamming spread region and Flame spread region. In this experiment, Particle size of four examined LOI, L.Point, H.Point, at the biggest size show high LOI. The surface area is connected with thermal conduction. The phenomena of combustion transition are governed by quantity of combustible gas generation in heating zone of cellulose insulation.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2008.10a
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• pp.135-136
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• 2008

EU-Reach Regulation 대비 유해물질 대체약품 개발 프로그램인 SVHC(Substance of very high concern)로부터 환경친화적인 방염제의 스크리닝으로 LOI 30이상의 Halogen-free 유기계 Organo-Phosphonate 화합물들이 유력한 후보로 선별되었으며 여기에 반응형 저에너지 타입 아(메타)크릴계 광기능성기를 도입하여 에너지 절감형이면서 친환경적인 가공약제를 개발 하였다. 먼저 열경화형 타입중에서도 면섬유에 취급이 용이한 DMP(dimethylphosphite)를 출발물질로한 N-Methylol type의 열경화형 인/질소 타입 알코올 함유 면섬유용 방염제를 제조한후 -OH기에 광반응형 아크릴 기능성기를 도입하여 개시제와 함께 광경화 방염가공 후 물성에 관한 특성를 관찰 하였다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2012.04a
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• pp.26-29
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• 2012

본 연구에서는 목분-폴리프로필렌 복합재의 연소성 및 열적특성을 평가하기 위하여 한계산소지수 실험 및 열중량 분석실험을 실시하였다. 목분-폴리프로필렌 복합재의 제조를 위하여 이축압출기를 활용한 압출공정과 사출성형기를 활용한 사출공정을 이용하였다. 그리고 복합재의 난연성능 향상을 위하여 난연제(4종류)를 첨가한 복합체의 화재성능을 평가하였다.

• Journal of the Korean Society of Safety
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• v.6 no.1
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• pp.14-25
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• 1991

The smouldering combustibility of cellulose insulation treated with boric acid-borax-alum as combustion retardants are examined by cigarette ignition method and electrical cardrige heater method. The alum to be required at an add on level of at least 12% by weight of cellulose treated with boric acid-borax-alum=2 ： 1 ： 2 fomulatlon if resistance to smouldering combustion by cigarette ignition is to be achived. The optimum electrical ignition source employed by electrical cartidge heater method was 23.2 watts(80V) power level The effectiveness of Alum as a third combstion retardant are acceptable both smouldering resistance and flame resistance at 18% level of all examined formulation.