• Journal of the Korean Society of Safety
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• v.26 no.6
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• pp.20-25
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• 2011

This study presents on the fire hazard analysis of communication cable in buildings. In order to analyze fire hazards for communication cable IEC 60332-1, UL 94 and cone calorimeter test are conducted. The number of cable used to experiment is 10 communication cable which are generally applied to data communication in buildings. The results show that 9 cables do meet the performance requirement of IEC 60332-1 and 8 cables are V-0 classification. IEC 60332-1 and UL 94 test are inadequate for fire hazard classification. The various parameters obtained by cone calorimeter test such as HRR, peak HRR, smoke production rate and so on. Also it is able to evaluate multiply fire hazard for communication cable with cone calorimeter test results.

• Journal of Adhesion and Interface
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• v.20 no.2
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• pp.61-65
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• 2019

In this study, phosphorus polyols, having a molecular weight of 880 to 1,560 g/mol, were synthesized by reacting phenylphosphonic dichloride (PPDC), allylphosphonic dichloride (APDC), and ethylene glycol (EG) in solvent, to enhance flame retardance of polyurethane. Phosphorus polyurethanes were polymerized using the synthesized phosphorus polyols, polycarbonate diol (PCD), and 4,4'-diphenylmethane diisocyanate (MDI) by a melt polymerization method. As increasing phosphorus contents of the phosphorus polyurethanes, we observed that the remaining char amount increased. This tendency was also confirmed in the following UL-94V test. We found that when the synthesized phosphorus polyols were applied, the resulting phosphorus polyurethanes show UL-94V0 grade at above 0.5 wt% phosphorus contents.

• Resources Recycling
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• v.16 no.4
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• pp.17-26
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• 2007

Inorganic shell powder waste was added to recycled polypropylene(COPP), and its effect on the mechanical properties and flammability was investigated. Compatibilizer(Polytail H) was added to improve mechanical properties of COPP/shell composites. Also three different flame retardants($Al_2O_3$, DBDPO, $Sb_2O_3$) were added to improve flammability. Experimental results indicated that addition of compatibilizer resulted in an improved mechanical properties, and especially impact strength approached that of 100 wt% COPP. Addition of flame retardant did not result in decreased mechanical properties. UL-94 flammability test indicated that COPP/shell composite did not show good flame retardancy, however, in the case of COPP/shell composites containing flame retardant showed good flammability. flammability was found $Sb_2O_3>Al_2O_3>DBDPO$ in this order. Finally, UL-94 V-0 grade was found in COPP/shell composite with $Al_2O_3$, compatibilizer, and 40 wt% shell, and COPP/shell composites with $Sb_2O_3$.

• Polymer(Korea)
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• v.31 no.4
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• pp.273-277
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• 2007

Cyclophosphazene derivatives were synthesized in order to use as a non-halogen flame retardant for ABS. Chlorocyclophosphazene was reacted with phenol, catechol, aniline, 1,2-diaminobenzene respectively, and each product was characterized by UL94 and LOI test for ABS resin. The physical properties of the sample containing these flame retardants were also characterized. The derivative synthesized from catechol showed best flame retardancy, and the derivative from phenol exhibited the flame retardancy in which the synergic effect was shown with novolac.

• Journal of the Korean Society of Safety
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• v.12 no.3
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• pp.173-178
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• 1997

The intrinsic flame retardant and heat resistant polymers such as PQXS [poly( quinoxaline )sulfide], PIQS [poly(isoquinoline)sulfide] and PQS [poly(quinoline)sulfide] were synthesized from 2, 3-dichloroquinoxaline, 1, 3-dichloroisoquinoline and 4, 7-dichloroquinoline. They were characterized by FT-IR, UV/Vis spectroscopy, DTA and elemental analysis. The melting point above $350^{\circ}C$ of the polymers show higher than that of the heat resistant PPS polymer(mp. $295^{\circ}C$), In the LOI test, the polymers exhibit an intrinsically high flame retardant property having the LOI values in the range of 41~42. The vertical burning test for the polymers also show an UL 94 V-0 performance.

• Fire Science and Engineering
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• v.20 no.3 s.63
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• pp.113-117
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• 2006

This study presents analysis of fire hazard of electrical heating pad. In order to analyze fire hazard fire experimental and flammability experiment is conducted. The fire experiment is conducted to simulate normal condition and abnormal condition such as breakdown of thermostat. Vertical burning test(UL 94) is conducted for the fire retardant experiment. Kinds of electric heating pad used for experiment are electric mat, fabric pad, vinyl pad. The results show that fire hazard is high in case of breakdown of thermostat with the rating voltage supply. And Material of electric heating pad has not fire retardant performance.

• KSBB Journal
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• v.5 no.3
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• pp.299-306
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• 1990

Escherkchla coli/Cownebacterium glutamicum shuttle vectors, pECCGl and pECCG2 were constructed by joining a 3.0 kb C. glutamicum cryptic plasmid pCBl and a 3.94 kb E. coli plasmid pACYC177. Using the plasmid pECCGl, various parameters involved in electroporation system including electric field strength, resistance, DNA concentration, cell concentration and growth stage were investigated independently and optimized for the high efficiency transformation of coryneform bacteria. Transformation efficiencies of 106 transformants/$\mu\textrm{g}$ of plasmid DNA were achieved with Corynebacterium glutamicum.

• Journal of Korean Academy of Nursing
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• v.22 no.4
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• pp.569-588
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• 1992

This study examined the relationship between the experience of stressful life events and somatic symptoms of urban women. Data were collected by interviewing 200 women from June to July 1, 1991. Vsable data work obtained from 162 of the women. Modified version of a stressful life events measurement tool developed p.5. Lee (1984) and the Somatic Discomfort Inventory by Wittenborn were used to measure the variables. Data were processed by an 5.p.5.5. program and analyzed. statistically for percentage, T-test, ANOYA and Pearson Correlation coefficient. Result of the Study are as follows : 1) The group total mean score of stressful life events was 92.66 $\pm$ 10.41. The higher scores in the $\boxDr$Test and school$\boxUl$ of the Extrapersonal factor, in the $\boxDr$Health problems$\boxUl$ of the Intrapersonal factor and $\boxDr$Conflict and differences within the family$\boxUl$ of the Interpersonal factor, factors. which a suggested by Neuman's model. 2) The group total mean score for somatic symptoms was 100.41$\pm$9.74. The higher scores were for the factors of $\boxDr$Fatigue (1.94)$\boxUl$, $\boxDr$Menopause (1.74)$\boxUl$, $\boxDr$Muscular system(1.67)$\boxUl$ and $\boxDr$Sleeping (1.67)$\boxUl$ 3) The mean scores of stressful life events were higher in the 40~60 age group, for middle school graduates(P＜.05), career women and those in nuclear families (P＞.05). 4) The mean scores of somatic symptoms were higher in the 45~60 age group, for middle school graduates, non career women and women with 5 or more children(P＜.05). 5) There was a positive correlation between the scores of stressful life events and somatic symptoms (r＝.585 P＜.05). The higher the level of stressful life events the higher the score of somatic symptoms, the results were consistent with the Extrapersonal, Intrapersonal and Interpersonal stress factors of Neuman's Health Care Systems. This research assessed the stressful life events of women, who play the most important role in the family for illness prevention and health promotion and suggested the importance of programs in the Primary Health Services to build basic coping resources.

• Applied Chemistry for Engineering
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• v.20 no.2
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• pp.234-240
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• 2009

$Mg(OH)_2$ particles were prepared by precipitation and a hydrothermal treatment to examine the effect of $MgCl_2$ concentration, alkali type and concentration, temperature, hydrothermal treatment on the formation of $Mg(OH)_2$ particles using full factorial design, as one of DOE (Design of experiment) methods. The primary particle size is similar to the secondary particle size for the samples after the hydrothermal treatment, where the average particle size of $Mg(OH)_2$ increased with increasing the concentration of $MgCl_2$ and hydrothermal temperature and decreasing alkali/Mg molar ratio. On the other hand, for the samples prepared from precipitation, the secondary particle size is larger than the primary particles due to aggregation. The difference in alkaline source is that the particles prepared from $NH_4OH$ exhibit the larger size with better dispersion than those from NaOH. Low density polyethylene and ethylene-co-vinyl acetate (LDPE-EVA) resin composed of the smaller secondary particle size of $Mg(OH)_2$ shows a higher limited oxygen index (LOI) at 50 and 55% loading, but the smaller primary particle size may result in a better grade in UL-94 tests. At the high loading of 60%, all samples with any preparation methods exhibit V-0 grade but the LOI value depends on not only primary particle size but also dispersion state.

• 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.