The improvement of flame retardancy of the foams based on NBR/GTR compounds was conducted by formulating various materials such as NBR, GTR, inorganic and phosphorus containing flame retardants, foaming agents, crosslinking agents and activators. The foaming properties, morphology, smoke density and...
The improvement of flame retardancy of the foams based on NBR/GTR compounds was conducted by formulating various materials such as NBR, GTR, inorganic and phosphorus containing flame retardants, foaming agents, crosslinking agents and activators. The foaming properties, morphology, smoke density and flame retardancy of the specimens were investigated using SEM, LOI tester, smoke density control system and cone-calorimeter. Generally, a phosphorus containing flame retardant reduces heat release rate and gas liberation, and increases the limiting oxygen index. The inorganic flame retardant such as Al(OH)_(3), Mg(OH)_(2) increases the limiting oxygen index and reduces the heat release rate with an increased CO yield due to char formation, and smoke suppressing effect. The char seems to intercept the oxygen transport and heat transfer into the core area. In the case of 100 ~ 80/0 ~ 20 (w/w) in the composition ratios of NBR/GTR, and 1/1.55 ~ 3.60 (w/w) in the ratios of the rubbers/flame retardants, The foams developed showed low heat release rate, high limiting oxygen index (28.0 ~ 39.3), closed or semi-closed cell with uniformity and reasonable expandability (225 ~ 250 %). The flame retardancy and foaming properties of NBR foams containing waste ground tire rubber (GTR) were studied. At the composition ratios of NBR/GTR, in 100/0 ~ 80/20 (w/w) and rubbers/flame retardants, 1/1.95 ~ 3.70 (w/w), the considerably optimized foams for flame retardancy were obtained with high limiting oxygen indices (LOI, 29.4 ~ 40.0), low heat release rate (HRR), closed/semi-closed cell of uniformity, and reasonable expandability (215 ~ 300 %). The LOI was increased and the heat release rate was decreased with increasing the amount of GTR content. The flame retarded NBR foams were prepared with metal hydroxides and various phosphorus/nitrogen-containing flame retardants. The dependency of the phosphorus content on thermal properties, flame retardancy, smoke density, and foaming properties were investigated in the foams. As a result, foaming properties and morphology of the flame retarded NBR foams with P/N flame retardants were similar to those of the foams without P/N containing flame retardants in the range of 0 ~ 10 phr of the flame retardants. The flame retardancy of the foams was improved with increasing phosphorus content and char formation under combustion atmosphere. The cone-calorimeter test and LOI index also were coincided with the TGA analysis quite well. The heat release rate (HRR), total heat release (THR), and effective heat of combustion (EHC) were decreased, whereas the carbon monoxide yield was increased with the increase of phosphorus content of P/N flame retardant. The smoke density values were closely related with CO yield values obtained by the cone-calorimeter test due to the high and hard char formation. In this study, flame retardancy and foaming properties of NBR/GTR foams with phosphorus/nitrogen-containing flame retardants were investigated. For TGA analysis of NBR/GTR foams, thermal properties were improved with increasing phosphorus content of flame retardants. Limiting oxygen index (LOI) was affected largely by foaming properties (cell structure, expandability, etc) and increased as using phosphorus/nitrogen-containing flame retardants due to the N/P synergistic effect for high and hard char formation. When the phosphorus/nitrogen-containing flame retardants were 10 phr, we could obtain foams with the highest LOI (34.0). In case of cone-calorimeter test, heat release rate was increased as LOI values were decreased. We could obtain foams with the lowest heat release rate, total heat release, and carbon monoxide yield when the phosphorus/nitrogen-containing flame retardants were 10 phr. Phosphorus/nitrogen-containing flame retardants had a considerable effect in the decrease of smoke density. It turns out that the dispersion of the additives and inner-pressure of the blends significantly influenced in determining the foaming properties. The influence of expandable graphite (EG) on flame retardancy and foaming properties of the NBR/GTR foams was studied. The foaming properties were similar to those of NBR/GTR foams without EG at the EG contents 10 ~ 30 phr. The LOI values were increased with increasing of the EG content due to intercept the oxygen transport and heat transfer into the core area. For cone-calorimeter test, the data showed the trends similar to the LOI experiment. When the composition ratios of the compounds of NBR/GTR were 100 ~ 0/80 ~ 20 (w/w), and the EG contents were 10 ~ 30 phr, we obtained high flame retardancy foams with low HRR, THR, and COY. The smoke density is similar to CO yield values obtained by the cone-calorimeter test. TGA analysis also showed the results approximately similar to those from the LOI and cone-calorimeter experiments. The blends of waste-polyethylene (W-PE)/waste-ethylene vinyl acetate copolymer (W-EVA) with inorganic and phosphorous flame retardants (i.e., aluminium hydroxide, magnesium hydroxide, and so on) were prepared by melt mixing techniques at different compositions and foamed. The flame retardancy and foaming properties of the blends, limiting oxygen index (LOI), heat release rate (HRR), carbon monoxide yield (COY), total heat release (THR), effective heat of combustion (EHC), expandability and cell structure were investigated using cone calorimeter, SEM, LOI tester and polarizing microscope. In the case of 50/50 (w/w) in the composition ratios of W-PE/W-EVA, and 1/1.75 ~ 2.20 (w/w) in the ratios of the resins/flame retardants, The foams developed showed low HRR, high LOI, closed cell with uniformity and reasonable expandability (1900 % or more). These results depend on crosslinking and foaming conditions, a char formation and smoke suppressing effect. Aluminium hydroxide had more effect in the increase of LOI than magnesium hydroxide, while magnesium hydroxide considerably affected the decrease of HRR and COY.
The improvement of flame retardancy of the foams based on NBR/GTR compounds was conducted by formulating various materials such as NBR, GTR, inorganic and phosphorus containing flame retardants, foaming agents, crosslinking agents and activators. The foaming properties, morphology, smoke density and flame retardancy of the specimens were investigated using SEM, LOI tester, smoke density control system and cone-calorimeter. Generally, a phosphorus containing flame retardant reduces heat release rate and gas liberation, and increases the limiting oxygen index. The inorganic flame retardant such as Al(OH)_(3), Mg(OH)_(2) increases the limiting oxygen index and reduces the heat release rate with an increased CO yield due to char formation, and smoke suppressing effect. The char seems to intercept the oxygen transport and heat transfer into the core area. In the case of 100 ~ 80/0 ~ 20 (w/w) in the composition ratios of NBR/GTR, and 1/1.55 ~ 3.60 (w/w) in the ratios of the rubbers/flame retardants, The foams developed showed low heat release rate, high limiting oxygen index (28.0 ~ 39.3), closed or semi-closed cell with uniformity and reasonable expandability (225 ~ 250 %). The flame retardancy and foaming properties of NBR foams containing waste ground tire rubber (GTR) were studied. At the composition ratios of NBR/GTR, in 100/0 ~ 80/20 (w/w) and rubbers/flame retardants, 1/1.95 ~ 3.70 (w/w), the considerably optimized foams for flame retardancy were obtained with high limiting oxygen indices (LOI, 29.4 ~ 40.0), low heat release rate (HRR), closed/semi-closed cell of uniformity, and reasonable expandability (215 ~ 300 %). The LOI was increased and the heat release rate was decreased with increasing the amount of GTR content. The flame retarded NBR foams were prepared with metal hydroxides and various phosphorus/nitrogen-containing flame retardants. The dependency of the phosphorus content on thermal properties, flame retardancy, smoke density, and foaming properties were investigated in the foams. As a result, foaming properties and morphology of the flame retarded NBR foams with P/N flame retardants were similar to those of the foams without P/N containing flame retardants in the range of 0 ~ 10 phr of the flame retardants. The flame retardancy of the foams was improved with increasing phosphorus content and char formation under combustion atmosphere. The cone-calorimeter test and LOI index also were coincided with the TGA analysis quite well. The heat release rate (HRR), total heat release (THR), and effective heat of combustion (EHC) were decreased, whereas the carbon monoxide yield was increased with the increase of phosphorus content of P/N flame retardant. The smoke density values were closely related with CO yield values obtained by the cone-calorimeter test due to the high and hard char formation. In this study, flame retardancy and foaming properties of NBR/GTR foams with phosphorus/nitrogen-containing flame retardants were investigated. For TGA analysis of NBR/GTR foams, thermal properties were improved with increasing phosphorus content of flame retardants. Limiting oxygen index (LOI) was affected largely by foaming properties (cell structure, expandability, etc) and increased as using phosphorus/nitrogen-containing flame retardants due to the N/P synergistic effect for high and hard char formation. When the phosphorus/nitrogen-containing flame retardants were 10 phr, we could obtain foams with the highest LOI (34.0). In case of cone-calorimeter test, heat release rate was increased as LOI values were decreased. We could obtain foams with the lowest heat release rate, total heat release, and carbon monoxide yield when the phosphorus/nitrogen-containing flame retardants were 10 phr. Phosphorus/nitrogen-containing flame retardants had a considerable effect in the decrease of smoke density. It turns out that the dispersion of the additives and inner-pressure of the blends significantly influenced in determining the foaming properties. The influence of expandable graphite (EG) on flame retardancy and foaming properties of the NBR/GTR foams was studied. The foaming properties were similar to those of NBR/GTR foams without EG at the EG contents 10 ~ 30 phr. The LOI values were increased with increasing of the EG content due to intercept the oxygen transport and heat transfer into the core area. For cone-calorimeter test, the data showed the trends similar to the LOI experiment. When the composition ratios of the compounds of NBR/GTR were 100 ~ 0/80 ~ 20 (w/w), and the EG contents were 10 ~ 30 phr, we obtained high flame retardancy foams with low HRR, THR, and COY. The smoke density is similar to CO yield values obtained by the cone-calorimeter test. TGA analysis also showed the results approximately similar to those from the LOI and cone-calorimeter experiments. The blends of waste-polyethylene (W-PE)/waste-ethylene vinyl acetate copolymer (W-EVA) with inorganic and phosphorous flame retardants (i.e., aluminium hydroxide, magnesium hydroxide, and so on) were prepared by melt mixing techniques at different compositions and foamed. The flame retardancy and foaming properties of the blends, limiting oxygen index (LOI), heat release rate (HRR), carbon monoxide yield (COY), total heat release (THR), effective heat of combustion (EHC), expandability and cell structure were investigated using cone calorimeter, SEM, LOI tester and polarizing microscope. In the case of 50/50 (w/w) in the composition ratios of W-PE/W-EVA, and 1/1.75 ~ 2.20 (w/w) in the ratios of the resins/flame retardants, The foams developed showed low HRR, high LOI, closed cell with uniformity and reasonable expandability (1900 % or more). These results depend on crosslinking and foaming conditions, a char formation and smoke suppressing effect. Aluminium hydroxide had more effect in the increase of LOI than magnesium hydroxide, while magnesium hydroxide considerably affected the decrease of HRR and COY.
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