고흡수성 중합 물질의 자연발화와 활성화 에너지 측정에 관한 연구

Abstract

This study was conducted to obtain experimental data for the establishment of preventive measures against fire accidents in the production and storage facilities of super absorbent polymers (sodium polyacrylate and potassium polyacrylate) developed for the convenience of daily life. Experiments were conducted on sodium polyacrylate and potassium polyacrylate, which are the main products of demand and production due to their excellent absorption capacity among various types of superabsorbent polymers. In order to investigate the spontaneous ignition temperature, apparent activation energy and correlation of these materials, experiments were carried out on each powdered material with different layer thickness. As a result, the following conclusions were obtained. 1) For sodium polyacrylate, the spontaneous ignition temperature varied depending on the thickness of the sample, 217.5 ℃ at a 3 cm thickness, 212.5 ℃ at a 5 cm thickness, 202.5 ℃ at a 7 cm thickness, and 187.5 ℃ at a 14 cm thickness. 2) For potassium polyacrylate, the spontaneous ignition temperature were 212.5 ℃ at a 3 cm thickness of the sample, 202.5 ℃ at a 5 cm thickness, 192.5 ℃ at a 7 cm thickness, and 177.5 ℃ at a 14 cm thickness. 3) For sodium polyacrylate, as the sample thickness increased, the spontaneous ignition temperature decreased. Similarly, for potassium polyacrylate, the spontaneous ignition temperature decreased with an increase in sample thickness. This is likely attributed to the thicker sample layers promoting the accumulation of heat inside. 4) The spontaneous ignition temperature of potassium polyacrylate is approximately 10 °C lower than that of sodium polyacrylate. Since a lower spontaneous ignition temperature indicates a higher hazard level, potassium polyacrylate is regarded as slightly more hazardous than sodium polyacrylate. 5) In case of sodium polyacrylate, the ignition induction time to reach the peak temperature was approximately 34 hours at a thickness of 3 cm, 76 hours at 5 cm, 143 hours at 7 cm, and 318 hours at 14 cm. 6) In the case of potassium polyacrylate, the ignition induction time to reach the peak temperature was approximately 42 hours at a thickness of 3 cm, 91 hours at 5 cm, 151 hours at 7 cm, and 300 hours at 14 cm. 7) The ignition induction time for both materials was observed to rise as the sample thickness increased. This is attributed to the slower transfer of heat to the interior of a thicker sample. 8) The calculated apparent activation energy for sodium polyacrylate was 44.92 kcal/mol with a correlation of 96.93 % while the apparent activation energy for potassium polyacrylate was 39.30 kcal/mol with a correlation of 99.5%. From comparison between the two samples, it is evident that potassium polyacrylate poses a higher risk of spontaneous ignition than sodium polyacrylate. Experiments have shown that super absorbent polymers can start spontaneous ignition above a certain temperature. Therefore, it is necessary to install storage facilities that consider heat dissipation and prevention of heat accumulation. In addition, due to the nature of the product, which must be handled in a dry state, safety measures are required to prevent ignition or dust explosion caused by an ignition source