• 한국응용과학기술학회지
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• 제23권4호
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• pp.328-339
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• 2006

The PU flame-retardant coatings (TTBAH, ATBAH-10C, -20C, and -30C) were prepared using the synthesized ATBAs and HDI-trimer as curing agent at room temperature. The physical properties of PU flame-retardant coatings with chlorine and phosphorus were inferior to those with phosphorus only and the properties were getting worse with increasing chlorine content. Flame retardancy was tested with three methods. With the vertical method, complete combustion time of ATBAHs were $259^{\sim}347$ seconds, which means that the prepared coatings are good flame-retardant. With the $45^{\circ}$ Meckel burner method, char lengths of the three prepared coatings were less than 2.9 cm, which indicates that the prepared coatings are first grade. With the limiting oxygen index (LOI) method, the LOI values of the three prepared coatings were in the range of $30^{\sim}35%$, which proves good flame retardancy of the prepared coatings. from the result of flame retardancy tests of the specimens that contain the same amounts of flame retarding compounds. it was found that the coatings containing both phosphorus and chlorine show higher flame retardancy than the coatings containing only phosphorus. This indicates that there exists, some synergy effect between coexisting phosphorus and chlorine.

• Composites Research
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• 제32권6호
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• pp.342-348
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• 2019

고분자 재료의 사용이 늘어남에 따라 난연성 고분자 재료에 대한 연구가 더욱 활발히 진행되고 있다. 고분자 재료의 난연성 향상을 위한 방법으로 제조된 섬유의 후처리 또는 섬유내 난연제의 도입에 관한 연구가 진행되고 있다. 많은 고분자들 중 탄소섬유 전구체인 폴리아크릴로니트릴(PAN)은 의류용으로도 많이 사용되고 있어서 낮은 난연성을 지닌 PAN으로 이루어진 소재의 난연성 향상이 절실히 요구되고 있다. 본 총설 논문에서는 PAN 섬유의 후처리(안정화 또는 화학반응)을 통한 난연성 PAN 섬유와, 유/무기 소재(실리카, 2차원 소재, 탄소나노튜브)과 함께 혼합하여 섬유로 제조하는 난연성 PAN 복합소재의 제조에 대한 연구를 소개하고자 한다.

• 한국물환경학회지
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• 제24권6호
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• pp.741-749
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• 2008

Many small-scale ponds that serve as ecological habitat, recreation and irrigation are faced to eutrophication problem, which causes aesthetic nuisance and ultimately loss of their functions. Thus accurate evaluation of the trophic state of these ponds is essential to provide rational information to the stakeholders so that they can develop effective management actions. In this study, the trophic state of a small pond (Wonheung) that experiencing water quality degradation due to vicinity land development was assessed using various Trophic State Indexes (TSIs) and statistical analysis including Principal Components Analysis (PCA) based on the field monitoring data obtained from May to December, 2007. The results showed that the pond is under eutrophic state with average total nitrogen (T-N) and total phosphorus (T-P) concentrations of $708.1{\mu}g/L$ and $59.3{\mu}g/L$, respectively. The factor loading plot obtained from PCA showed distinct two influencing factors, PC 1 and PC 2. PC 1 was grouped by T-P, Chlorophyll a (Chl-a), suspended solids (SS), TN/TP ratio, and transparency that all strongly related to the eutrophication state, while PC 2 by temperature, conductivity, dissolved oxygen (DO) and turbidity that explains the seasonal water quality variations. The limiting factor was identified as light rather than phosphorus by both T-N/T-P ratio and TSI indexes analysis. The results and methodology adopted in this study can be used for water quality assessment for other small ponds and lakes.

• 폴리머
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• 제26권2호
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• pp.200-208
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• 2002

난연성분인 트리클로로벤조산(TBA)의 함량을 10, 20, 30 wt%로 변화시키면서 아디프산, 1,4-부탄디올 및 트리메틸올프로판과 축중합을 하여 트리클로로 락톤 변성폴리에스테르(TAPTs)를 합성한 후에, TAPT류와 이소시아네이트인 Desmodur IL을 블렌드하여 2성분계 폴리우레탄 난연 도료를 제조하였다. 제조된 난연도료의 도막물성을 측정한 결과, 결코 비난연도료보다 물성이 떨어지지 않음을 알았다. 또한 난연도료의 3종류 난연성 시험결과, 수직법에서 TBA 함량 20 wt% 이상에서 불꽃에 타지 않았고, LOI 연소성 시험에서 TBA 함량 20, 30 wt%시 25%와 27%의 LOI값을 나타내었으며, $45^{\circ}$ Meckel burner법에서는 탄화길이가 3.6-5.2 cm로서 난연 1급에 해당되었으므로 이를 미루어 난연효과가 좋은 난연도료임을 알 수 있었다.

• Elastomers and Composites
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• 제51권2호
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• pp.147-153
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• 2016

Polyvinyl chloride (PVC) has been used as a general-purpose polymer because of its lower cost, good durability and mechanical properties compared to other materials. However, PVC is vulnerable to heat deformation and generates a toxic gas like hydrogen chloride. Therefore, it is important to delay or prevent the flame retardancy and thermal degradation of the PVC during the processing. It was reported that aluminum trihydroxide (ATH) improved flame retardancy as well as smoke inhibition of the virgin polymer. In this study, PVC composites by addition of ATH were compounded in a modular intermeshing co-rotating twin screw extruder. The PVC composites with different concentrations of ATH (0~5 phr) were analyzed. Flame retardancy of the PVC composite significantly increased depending on the ATH concentration. LOI of the composite also increased with the concentration of ATH. There were no significant differences for the thermal properties of the PVC composites with ATH.

• 폴리머
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• 제37권4호
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• pp.437-441
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• 2013

A novel sulfonate flame retardant, 1,3,5,7-tetrakis(phenyl-4-sodium sulfonate)adamantane (FR-A), was successfully synthesized from 1-bromoadamantane in sequential four-step reactions involving Fiedel-Crafts phenylation, sulphonation, hydrolysis, and neutralization. The success of synthesis was confirmed by FTIR spectra, $^1H$ NMR spectra, elemental analyses and mass spectra. The effect of FR-A on the flame retardacy of polycarbonate (PC) has been studied. Limiting oxygen index (LOI) and thermogravimetric analysis (TGA) showed that this novel sulfonate flame retardant had effective flame retardancy on polycarbonate (PC). With a small amount (0.08 wt%) of FR-A, the flame retardancy of PC was improved obviously, which got to UL 94 V-0 rating. TGA and DTA curves demonstrated that the additive raised the degradation rate of PC by promoting the quick formation of an insulating carbon layer on the surface, and confirmed that the flame retardant mechanism of PC/FR-A system was similar to potassium diphenylsulfone sulfonate (KSS).

• 한국화재소방학회논문지
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• 제20권4호
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• pp.72-76
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• 2006

고분자/점토의 nanocomposite는 고분자에 소량의 점토를 첨가해도 물리적, 기계적, 열적 특성이 증가하기 때문에 최근 이에 관련된 연구가 증가되고 있다. 특히 montmorillonite(MMT)와 같은 smectite 계열의 점토는 높은 종횡비, 판형의 층상구조, 경제성 때문에 산업적으로 이용가치가 많다고 할 수 있다. 본 연구에서는 PE/MMT nanocomposite는 고분자를 용융시킨 후 점토를 삽입하여 시편을 제조하였다. 나노입자의 구조는 XRD 및 TEM을 이용하여 확인하였고, 난연성은 LOI, 탄화층 생성량, 연기중량농도의 측정을 통하여 검토하였다. 또한 PE/MMT nanocomposite의 열적 안정성은 DTG-DTA 분석을 통하여 검토하였다. 그 결과 종래의 화합물보다 그 특성이 보강되었다. 난연성은 연소시 탄화층 형성에 의하여 증가 되었음을 확인할 수 있었다.

• 방사선산업학회지
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• 제17권3호
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• pp.225-232
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• 2023

In this study, poly(ethylene-co-vinyl acetate)/magnesium hydroxide (EVA/MDH) composites were prepared by electron beam crosslinking. EVA as a matrix resin and MDH as a flame retardant were melt-blended and compression molded to prepare EVA/MDH composites. The prepared EVA/MDH composites were electron beam-irradiated at various absorbed doses of 50~200kGy. The effects of electron beam irradiation on the gel content, tensile strength, elongation-at-break, thermal properties, and flame retardancy of the composites were investigated. The gel content and tensile strength increased, while the elongation-at-break decreased with an increase in the absorbed dose due to the formation of crosslinked network structures. In addition, the thermal stability and flame retardancy improved as the absorbed dose increased. Therefore, the EVA/MDH composites prepared in this study can be used as an insulation material for flame-retardant and heat-resistant wires and cables.

• 한국화재소방학회논문지
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• 제29권2호
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• pp.25-32
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• 2015

라이오셀 섬유의 열 안정성과 내산화성을 향상시키기 위하여 $Na_3PO_4$ 수용액으로 내염화 처리를 실시하였다. 다양한 공정조건으로 라이오셀 섬유를 내염화 처리한 후 열 안정성과 내산화성을 측정 및 분석하고 그에 따른 메커니즘을 고찰하였다. 내염화 처리된 라이오셀 섬유의 적분 열분해 온도(integral procedural decomposition temperature, IPDT)와 활성화 에너지(activation energy, $E_a$)값은 각각 약 30, 160%로 향상된 것을 알 수 있었다. 이는 $Na_3PO_4$가 연소 시 에스테르화 반응, 탈수소화 반응 및 C-C 결합의 분해반응으로 char 형성을 촉진하여 섬유 표면에 보호층을 형성하여, 고분자 수지 내부로 산소와 열 공급을 물리적으로 차단하여 열 안정성과 내산화성이 향상된 것으로 판단된다. 이러한 결과를 바탕으로, $Na_3PO_4$ 수용액을 이용하여 열 안정성과 내산화성이 향상된 라이오셀을 제조하였고, 내염화 처리공정의 최적화된 인자 및 메커니즘을 고찰하였다.

• 한국안전학회지
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• 제26권4호
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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.