Magnesium Hydroxide and Magnesium Oxide in Oxidation and Burning of Polypropylene
Jozef Rychlý *
Polymer Institute, Slovak Academy of Sciences, Dúbravská cesta 11, 84541 Bratislava, Slovakia.
Martina Hudáková
Fire Research Institute, Ministry of Interior of the Slovak Republic, Rožňavská 11, 83104 Bratislava, Slovakia.
Lyda Rychlá
Polymer Institute, Slovak Academy of Sciences, Dúbravská cesta 11, 84541 Bratislava, Slovakia.
Ivica Janigová
Polymer Institute, Slovak Academy of Sciences, Dúbravská cesta 11, 84541 Bratislava, Slovakia.
Katarína Csomorová
Polymer Institute, Slovak Academy of Sciences, Dúbravská cesta 11, 84541 Bratislava, Slovakia.
Ivan Chodák
Polymer Institute, Slovak Academy of Sciences, Dúbravská cesta 11, 84541 Bratislava, Slovakia.
*Author to whom correspondence should be addressed.
Abstract
Magnesium hydroxide eliminates DSC exotherm of polypropylene oxidation and thus the peroxidation process. At the same time, non-isothermal thermogravimetry experiments show that the temperature of the maximum rate of volatiles released due to polypropylene decomposition is significantly higher than that from original polypropylene. It appears that in the presence of magnesium hydroxide, the degradation products are not formed predominantly from decomposition of peroxides but from direct scissions of polypropylene chains. Chemiluminescence experiments confirmed that magnesium ions in alkaline conditions have the activating effect on oxygen from surroundings contributing thus to the more pronounced oxidation of soot and to the decrease of the smoke released during polypropylene burning. The links with the burning of the polypropylene with alkaline magnesium compounds were searched.
Keywords: Magnesium hydroxide, magnesium oxide, differential scanning calorimetry, thermogravimetry, chemiluminescence, heat release rate, cone calorimeter.