engleski

Effect of magnesium hydroxide addition on the mechanism of thermal degradation of poly(ethylene oxide)

Poly(ethylene oxide) (PEO) is a semi-crystalline, biodegradable and water-soluble polymer of considerable industrial significance, which finds applications in many different branches of industry [1]. On the other hand, magnesium hydroxide (Mg(OH) 2 ) is a very important inorganic compound and it can be used as halogen-free flame-retardant for polymers. Simultaneously in polymer materials it acts as reinforcing agent, flame retardant, as well as smoke suppressant additive with low or zero emissions of toxic or hazardous substances [2]. Different methods for obtaining magnesium hydroxide are well known [3-4] but for this work, it has been synthesized via chemical precipitation method from sea bittern residual after production of sea salt from sea water. In order to obtain high purity magnesium hydroxide, clear limewater ( = 1.54 gL -1 ) as a precipitation agent was added in the sea bittern in a stoichiometric amount. The chemical reaction between magnesium ions from sea bittern and clear limewater produces magnesium hydroxide particles of fibre-like morphology (diameter ~ 10-20 nm ; length ~ up to 400 nm) agglomerated into larger structures. Thermal degradation and kinetic analysis of the thermal degradation of PEO have already been in focus of many studies and widely reported in the literature 5. Likewise, the thermokinetic study of magnesium hydroxide obtained from seawater has also been performed (6). However, no information about the kinetic analysis of the non-isothermal thermogravimetric degradation of PEO/Mg(OH) 2 composites couldn’t be found in the literature. Hence, the main goal of this work is to investigate the effect of Mg(OH)2 addition on the mechanism of thermal degradation of PEO. The PEO/Mg(OH) 2 composites were prepared via hot melt extrusion. Non-isothermal thermogravimetry in an inert atmosphere at four different heating rates was performed. The obtained data were utilized for the kinetic analysis using the isoconversional Friedman method in combination with multivariate nonlinear regression method incorporated in the Netzsch Thermokinetics 3.1 software. The kinetic parameters (activation energy, pre-exponential factor and kinetic model) were calculated.

Magnesium hydroxide, Poly(ethylene oxide), Thermal degradation, Kinetics

nije evidentirano