engleski

Kinetics of thermo oxidative degradation of polyethylene composites

Low density polyethylene (LDPE) is the most widely used commercial thermoplastic polymer because of good combination of properties, high chemical resistance, good mechanical properties and of low cost. It is mostly used in film production for the packaging because of their high tear strength, good barrier properties and impact strength. The production of polymer nanocomposites allowed important improvements in the properties of polymers, namely mechanical, thermal and gas-barrier properties, by using small amounts of clay. The new properties resulting from interactions between the polymeric matrix and nanoparticles make polymer nancomposites very attractive for a wide range of uses. Polyethylene composites were melting compounded with various amounts of zeolite TMAZ 7 and nanofiller Cloisite 20A. In order to investigate the thermal stability the kinetics of thermal decomposition of the prepared composites has been monitored. Thermal behaviour of polymer composites is important in the determination of end use applications and processing methods of polymer articles. Thermal properties were determined by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). DSC is used to determine the thermal transition of a polymer such as melting, degradation, crystallization and glass transition temperatures. TGA was performed and the obtained results were the initial degradation temperature (T90), temperature of maximum decomposition rate (Tmax) and carbonated residue. The obtained results were used to calculate the activation energy (Ea) according to Kissinger–Akahira-Sunose (KAS) method. The results showed that the addition of zeolite and nanofiller effect the thermal properties of polyethylene composites depending on their concentration in samples.

Low density polyethylene; filler; composite; thermal stability; activation energy

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