• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.46-50
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• 1999

Effects of $(NH_4)_2HPO_4$ and boron compounds ($Na_2B_4O_7:H_3BO_3=5:1\;ratio$) on the flame retarding characteristics of the surface modified wood powder-filled polypropylene composites were studied experimentally. The mechanical properties of m-phenylene dimaleimide(PDMI)-modified polypropylene composite were also compared with those of unmodified one. The flame retardance of $(NH_4)_2HPO_4$-modified wood powder composites was more improved than that of boron compounds-modified one. The impact strength of composites increased and the tensile strength of those decreased progressively with an increase of wood powder loading. The mechanical properties of modified polypropylene composites are more improved than those of unmodified one. The tensile strength also increased marginally with increasing the concentration of flame retardants, yielding a maximum when the concentration of flame retardant is 25.0 wt %. And the tensile strength of the composite was increased up to 16 wt % with increasing concentration of PDMI.

• Polymer(Korea)
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• v.31 no.5
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• pp.404-409
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• 2007

Polyurethane nanocomposites with inorganic nano fillers for the improvement thermal stability were prepared by the urethane reaction. Fire retardation properties of polyurethane nanocomposites were investigated by cone calorimeter and limited oxygen index (LOI). Maximum heat release rate of MMT-PU and $Bi_2O_3-PU$ polyurethane nanocomposites were decreased as 50% than polyurethane matrix and fire retardation properties of $MMT/Bi_2O_3-PU$ nanocomposte had the best improvement. The LOI of polyurethane nanocomposites also were improved as filling fillers in the nanocomposites over 20. The maximum heat release rates of MMT-PU, $Bi_2O_3-PU\;and\;MMT/Bi_2O_3-PU$ polyurethane nanocomposites were 764, 707, $635kW/m^2$, respectively and $MMT/Bi_2O_3-PU$ polyurethane nanocomposite exhibited the highest value of fire-retardant. We confirmed that polyurethane nanocomposites improved the fire retardation properties.

• Journal of the Korean Applied Science and Technology
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• v.24 no.3
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• pp.287-295
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• 2007

Three phosphorus functional groups were introduced in one structural unit of polymer backbone to enhance the flame retardancy of PU coatings. In the first step, we synthesized tetramethylene bis(orthophosphate) (TBOP) that contained two phosphorus functional groups in one structural unit. In the next step, we synthesized modified polyesters (ATBTP-10C, -20C, -30C) that contained triphosphorus group using TBOP, 1,4-butanediol, trimethylolpropane, adipic acid, and another functional monomer, phenylphosphonic acid (PPA). The amount of PPA in ATBTPs was adjusted from 10 wt% to 30 wt%. The structure and characteristics of ATBTPs were examined using FT-IR, NMR, GPC, and TGA analysis. From the thermo-behavior test of diphosphorus modified polyester (ATBT) and ATBTPs, the afterglow of ATBT, ATBTP-10C, ATBTP-20C, and ATBTP-30C were 24.7, 27.1, 29.0, and 31.7%, respectively. It was found from this result that the afterglow increased with the amount of PPA component.

• Advances in materials Research
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• v.4 no.2
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• pp.97-111
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• 2015

Polypropylene short fiber (PP)-clay particulate-epoxy ternary composites were prepared by reinforcing PP short fiber and clay particles in the range of 0.1 phr to 0.7 phr into epoxy resin. Prepared hybrid composites were characterized for their mechanical, thermal and flame retardant properties. The obtained results indicated an increase in impact resistance, tensile strength, flexural strength and Young's modulus to an extent (up to 0.5 phr clay and 0.5 phr PP short fiber) and then decreases as the reinforcing phases are further increased. The thermal stability of these materials are found to increase up to 0.2 phr clay and 0.2 phr PP addition, beyond which it is decreased. Addition of clay is found to have the negative effect on epoxy-PP short fiber composites, which is evident from the comparison of mechanical and thermal properties of epoxy-0.5 phr PP short fiber composite and epoxy-0.5 phr PP short fiber-0.5 phr clay composite hybrid. UL-94 tests conducted on the composite hybrids have showed a reduction in the burning rate. Morphological observations indicated a greater fiber pull with the addition of clay. The performed tests in the present study indicated that materials under investigation have promising applications in construction, agriculture and decorative purposes.

• Fibers and Polymers
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• v.3 no.3
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• pp.91-96
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• 2002

Polyhydroxyamides derivatized with trifluorormethyl ether and trifluoromethyl ester groups were investigated as possible candidates for a new flame retardant polymer. Model compounds for these derivatized polyhydroxyamides were synthesized and their cyclization chemistry was investigated. The model compound study revealed that trifluorornethyl ester group containing model compounds can cyclize on heating, while trifluoromethyl ether group containing model compounds cannot. The non-fluorinated ether and ether derivatives behaved similarly. The trifluoromethyl ester derivatized polyhydroxyamides were synthesized according to the procedures for the model compounds. TGA characterization revealed that the fluorinated polymers have nearly same thermal stability as the underivatized PHA after cyclization.

• Proceedings of the KAIS Fall Conference
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• 2003.06a
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• pp.340-342
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• 2003

본 연구의 목표는 난연화를 위한 기존 공법의 단점 보완과 환경 친화적인 난연제를 사용한 비 난연 XLPE 케이블의 난연화 방법과 최적의 난연 코팅액 배합에 있다. 전력용, 통신용 등과 같이 고난연성이 요구되는 경우 기존 컴파운드 방법으로는 난연제를 다량으로 첨가하여 사용하며, base polymer와의 혼합성, 기계적인 물성에도 영향을 끼쳐서는 안되는 등 여러 가지 요구 조건을 만족시켜야 하는 문제점을 가지고 있다. 각 난연 코팅액에 따른 코팅 표면을 고찰한 결과 모든 코팅의 표면은 깨끗하였으며, 코팅층의 두께는 약 10～20 ㎛로 일정하게 코팅이 되었다. Mg(OH)₂/Zinc Borate의 경우는 무게비(wt％)가 1 : 0.5, 1: 0.6에서 난연 효과를 보였으나. 1 : 0.7이상에서는 유연성이 떨어져 코팅층의 균일이 발생하여 연소 테스트시 난연 효과가 떨어지는 현상을 볼 수 있었다. Mg(OH)₂/AF100 S/Zinc Borate의 경우는 AF100 S의 첨가량이 증가할수록 탄화막 형성되어 난연성이 향상되었다.

• Polymer(Korea)
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• v.39 no.3
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• pp.433-440
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• 2015

Aluminum trihydroxide (ATH) has been commonly employed as a flame retardant for ethylene vinyl acetate (EVA) copolymers. In the present work, ATH was obtained from a recycling process of multi-layer packaging film wastes. EVA/ATH composite samples were prepared using a two roll-mill and flame retardancy of EVA/ATH composites were examined using limiting oxygen index (LOI) and flame retardancy test (UL94). We observed excellent flame retardancy in case of adding 150 phr or more of recycled ATH to EVA. Particle size and specific surface area play crucial roles in LOI value and UL-94 classification of the EVA/ATH composites. Smaller particle size and higher specific surface area of ATH was found out to improve the flame retardancy. Regarding tensile properties, crosslinked EVA/ATH compounds which is practically used for electric cables had similar to or even better tensile property values than the ones without ATH.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.260-260
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• 2010

In recent years, polymer/clay nanocomposites have generated a great interest, both in industry and in academia, because they often exhibit remarkable improvement in material properties when compared with the virgin polymer or conventional micro and macro-composites. Among these properties are stiffness, strength, dimensional stability and permeability. [1-3] The dispersion of hydrophilic silicates in a hydrophobic matrix like Polyethylene (PE) is difficult because of the difference in character between PE and Montmorillonite (MMT). Therefore, it is necessary to modify PE with polar groups, which can increase the hydrophilicity of PE. In this study, High density polyethylene (HDPE)/$Mg(OH)_2$/Montmorillonite (MMT) nanocomposites having a various compositions were prepared by a melt blending technique with an internal mixer and properties namely mechanical, morpology, rheological and thermal properties were investigated

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.3
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• pp.218-222
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• 2003

본 연구의 목표는 난연화를 위한 기존 공법의 단점 보완과 환경 친화적인 난연제를 사용한 비 난연 XLPE 케이블의 난연화 방법과 최적의 난연 코팅액 배합에 있다. 전력용, 통신용 둥과 같이 고난연성이 요구되는 경우 기존 컴파운드 방법으로는 난연제를 다량으로 첨가하여 사용하며, base polymer와의 혼합성, 기계적인 물성에도 영향을 끼쳐서는 안 되는 등 여러 가지 요구 조건을 만족시켜야 하는 문제점을 가지고 있다. 각 난연 코팅액에 따른 코팅 표면을 고찰한 결과 모든 코팅의 표면은 깨끗하였으며, 코팅층의 두께는 약 10-20㎛로 일정하게 코팅이 되었다. TBBA/Sb₂O₃, TBBA/Zinc Borate의 무게비(wt%)가 1:0.7 이상부터 난연 효과를 보였다. 또한 Mg(OH)₂/Zinc Borate의 경우는 무게비(wt％)가 1:0.5, 1:0.6에서 난연효과를 보였으나, 1:0.7 이상에서는 난연 효과가 떨어지는 현상을 보였다. Mg(OH)₂/AF100 S/Zinc Borate의 경우는 AF100 S의 첨가량이 증가할수록 난연성이 향상되었다. 난연 코팅액의 열 분해 거동을 비교한 결과, Mg(OH)₂/Zinc Borate의 경우 초기 분해 온도가 유기계 난연제를 사용하였을 경우보다 늦어졌으며, 최종 잔류 탄화물 양도 많이 생성되었다. Mg(OH)₂/AF100 S/Zinc Borate의 경우 난연 효과를 상승을 위해 인계 난연제(AF100 S)를 첨가하였으나. 오히려 초기 분해온도가 빨라졌으며 잔류 탄화물의 양도 적게 나타났다. 그러나 연소 테스트 결과 가장 우수한 난연 효과를 보였다.

• Fire Science and Engineering
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• v.25 no.5
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• pp.69-75
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• 2011

It was performed to test the combustive properties of low density polyethylene and ethylene vinyl acetate (LDPE-EVA) composite by the addition of magnesium hydroxide. Flame retardant of natural magnesium hydroxide was added to the mixture of LDPE-EVA in 40 to 80 wt% concentration. The composite was compounded to prepare specimen for combustive analysis by cone calorimeter (ISO 5660-1). Comparing with virgin LDPE-EVA, the specimens including the magnesium hydroxide had lower flashover possibility. It is supposed that the combustive properties in the composites decreased due to the endothermic decomposition of magnesium hydroxide. The specimens with magnesium hydroxide showed both the lower total heat release rate (THR) and lower CO production rate than those of virgin polymer. As the magnesium hydroxide content increases, the total smoke release (THR) and smoke extinction area (SEA) decreased.