• Composites Research
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• 제35권5호
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• pp.359-364
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• 2022

Polymers are inherently vulnerable to flame, which limits their application to various high-tech industries. In addition, environmental regulations restrict the use of halogen-based flame retardants which has best flame-retardant effect. There are inorganic flame retardants and phosphorous flame retardants as representative non-halogen-based flame retardants. However, high content of flame retardants is required to impart high flame retardancy of the polymers, and this leads to a decrease in mechanical properties. In this research, a new approach for inorganic flame retardant-based polymer composites with high mechanical properties and flame retardancy was suggested. Inorganic flame retardants called as magnesium oxysulfate whisker (MOSw) were used in this research. MOSw can extinguish fire by releasing water and non-combustible gases when exposed to flame. In addition, they have reinforcing effect when added into the polymer with its high aspect ratio. Expandable graphite (EG) was used as a flame-retardant supplement by helping to form a more dense char layer. Through this research, it is expected that it can be applied to various industries requiring flame retardancy such as automobile, and architecture by replacing halogen-based flame polymer composites.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.370-370
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• 2006

Thermoplastic elastomer gels, which has molecular networks composed of a microphase-separated multiblock copolymer swollen to a large extent by a low volatility mid-block selective solvent such as white oil have various applications. In this particular study, the effect of several network-forming nanoscale fillers such as two different graphite particles and carbon nanotube on the properties of TPE gels prepared from a microphaseordered poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) triblock copolymer with an EB compatible white oil was studied. The linear viscoelastic behavior, sol-gel transition, x-ray diffraction and mechanical properties were discussed. The properties of thermoplastic elastomer gels hybrid with graphite prepared by mixing Poly(styrene-b-ethylene-co-butylene)-b-styrene) with paraffin oil and different amount of expandable graphite were found to increase the mechanical properties at only lower graphite concentration but tends to decrease when paraffin oil/SEBS ratio is lower. The gelation temperature is the same for all TPE gels with different amounts of graphite. Both storage (G') modulus loss (G") modulus of TPE gels slightly increase with addition of graphite.

• 한국건축시공학회지
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• 제18권6호
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• pp.559-567
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• 2018

외단열 마감 공법에서 사용되는 바탕조정재는 화재가 발생하는 경우 얇은 마감과 폴리머의 연소로 인해 표면부가 급속하게 붕괴되어 화재에 취약한 소재이다. 본 연구에서는 열적 성능이 우수한 팽창 흑연을 사용할 경우 바탕조정재의 성능을 개선할 수 있을 것으로 기대하였다. 실험결과, 팽창흑연을 사용한 바탕조정재는 부착강도 저하 및 물흡수계수 등의 감소가 발생하는 문제점이 있으나 플라이애시와 실리카흄을 사용하여 물리적 성능이 향상되는 것으로 나타났다. 팽창흑연을 사용한 바탕조정재는 복합 단열 시험체 표면의 페놀폼은 화염에 의한 표면 뚫림이 나타나지 않아 열원의 투과를 감소시킬 수 있을 것으로 나타났다.

• 한국결정성장학회지
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• 제23권5호
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• pp.235-240
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• 2013

그래핀(Graphene)은 전기 전도성 및 열전도성이 우수하고 1 nm 수준의 초 박막 형 필름 소재를 제조할 수 있다는 장점으로 인하여, 차세대 트랜지스터 소자 및 디스플레이 장치에 적용 가능한 방열 소재로서 많은 연구가 활발히 진행되고 있다. 또한 CVD(chemical vapor deposition)제조법으로 합성된 그래파이트(Graphite)는 구조의 단순성 및 유연성 때문에 안정하고 열에 강한 탄소계 방열소재로 주목 받고 있다. 본 연구는 열전도도가 우수한 폼(foam)형태의 구리를 촉매로 상압과 진공에서의 CVD법을 이용하여 그래핀을 성장시킨 후 구리 폼의 기공 안에 다양한 종류의 그래파이트(Natural graphite, expandable(/expanded) graphite, etc)를 복합 및 안정화시켜 기존보다 높은 열전도도를 가지는 방열소재를 개발하였다. 제조된 금속폼/그래파이트 소재를 OM(optical microscopy)과 SEM(scanning electron microscopy)을 이용하여 표면을 확인하였고 DSC(Differential Scanning Calorimetry), 아르키메데스 법을 활용한 비열, 밀도 결과를 확보하였다. 또한 LFA(Laser Flash Analysis)를 이용하여 열 확산계수 예측을 통한 열전도 특성을 평가하였다.

• 한국건설순환자원학회논문집
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• 제7권4호
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• pp.395-404
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• 2019

외단열 마감 공법에서 사용되는 바탕조정재는 화재가 발생하는 경우 얇은 마감과 폴리머의 연소로 인해 표면부가 급속하게 붕괴되어 화재에 취약한 소재이다. 본 연구에서는 열적 성능이 우수한 팽창 흑연을 사용할 경우 바탕조정재의 성능을 개선할 수 있을 것으로 기대하였다. 실험결과, 팽창흑연을 사용한 바탕조정재는 부착강도 저하 및 물흡수계수 등의 감소가 발생하는 문제점이 있으나 플라이애시와 실리카흄을 사용하여 물리적 성능이 향상되는 것으로 나타났다. 팽창흑연을 사용한 바탕조정재는 복합 단열 시험체 표면의 페놀폼은 화염에 의한 표면 뚫림이 나타나지 않아 열원의 투과를 감소시킬 수 있을 것으로 나타났다.

• Elastomers and Composites
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• 제52권1호
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• pp.27-34
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• 2017

In this experiment, blends of ethylene vinyl acetate rubber (EVM) with a vinyl acetate (VA) content greater than 40 wt% and ethylene propylene rubber (EPM) were prepared by mechanical mixing; a number of parameters of the blends, including oil resistance, morphological and dynamic mechanical properties and flame retardancy, were subsequently measured. In the $100^{\circ}C$ oil resistance test, both the ammonium polyphosphate/dipentaerythritol/expandable graphite (APP/DPER/EG) and aluminum hydroxide (ATH) flame retardant systems showed an increase in volume change with increasing EPM content. For the ATH system, the dispersion shape was coarse and aggregation was observed. The results of a dynamic mechanical test showed slightly higher E' and E'' for the APP/DPER/EG flame retardant system when compared to the single ATH system. For both the APP/DPER/EG and ATH systems, the limited oxygen index (LOI) tests performed at increasing content of EPM showed a LOI value higher than 30, indicating excellent flame resistance.

• Elastomers and Composites
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• 제52권2호
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• pp.105-113
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• 2017

The curing behavior, mechanical properties, hot-air aging resistance, abrasion properties,thermal properties, etc., of EVM/EPM/APP (ammonium polyphosphate)/DPER (dipentaerythritol)/EG (expandable graphite) and EVM/EPM/ATH (aluminium trihydroxide) flame retarding systems in ethylene vinyl acetate rubber (EVM) blends with EPM (ethylene propylene rubber) were sequentially examined. For both flame retarding systems, the torque values increased with the content of EPM rubber and with the vulcanization time. As the content of EPM rubber increased, the scorch time became shorter, whereas the optimum cure time followed an increasing trend. For the EVM/EPM/APP/DPER/EG flameretarding system, as the content of EPM rubber increased, the hardness did not change,whereas the tensile strength and elongation at break decreased. A hot-air aging resistance test at $150^{\circ}C$ showed that the heat resistance decreased with the EPM content regardless of the kinds and contents of flame retardants. As the EPM content increased, the abrasion rate became higher and the abrasion resistance of the EVM/EPM/APP/DPER/EG flame retarding systems exceeded that of the EVM/EPM/ATH flame retarding counterparts. In comparison with the EVM/EPM/ATH flame retarding systems, the thermal stability of the EVM/EPM/APP/DPER/EG flame retarding system showed an increasing tendency.

• 한국재료학회지
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• 제27권2호
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• pp.113-118
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• 2017

Natural and expandable graphites were chemically treated in acidic aqueous solutions such as acetic acid or mixtures of acetic acid and nitric acid. Structures and thermal conductivities of the as-treated graphites were characterized in detail. Both graphites were significantly oxidized in the mixed acidic solution of $H_2SO_4$ and $HNO_3$, which condition was generally used for the oxidation of carbon nanotubes. This considerable oxidation of graphites caused a depression of their thermal conductivity. The structural characteristics, obtained by XRD and XPS, show that the graphites treated in the relatively weak acidic conditions (acetic acid or mixture of acetic acid and nitric acid) were quite similar to the untreated graphites. However, the thermal conductivities of both acidic-treated graphites were remarkably increased.

• 대한건축학회논문집:구조계
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• 제33권12호
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• pp.71-80
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• 2017

The purpose of this study is to applied reinforcement method at the joint part of the sandwich panel. Becasue the joint part of the sandwich panel has a disadvantage that flame spreads fast inside steel plates in the event of fire, leading to a big fire rapidly. In this study, the combustion performance was measured through KS F ISO 13784-1 "Reaction-to-fire tests for sandwich panel building systems" according to the application of reinforcement method to prevent flame from being brought into the internal joint of the sandwich panel. For the reinforcement inside the panel, the tape produced using expanded graphite-based heat-expandable glass fiber was attached. As a result, it was confirmed that the prevention of flame from being brought into the internal joint could delay the flash over time and the collapse of the test specimen.