Study of the thermo-oxidative degradation behavior of isotactic polypropylene with the varying ethylene content

Abstract

The thermo-oxidative degradation behavior of isotactic polypropylene is studied as a function of varying ethylene and oxygen concentration effects by means of gel permeation chromatography (GPC) measurement. The thermal stability of three types of isotactic polypropylene viz. iPP, ePP1, ePP2 which contains 0, 0.5, 2.7 wt% of ethylene, respectively having similar average molecular weights and molecular weight distribution ( w/ n) is studied in solution at 453 K. Under this condition, the changes of molecular weight and w/ n in isotactic polypropylene samples are decreased with the increase of ethylene. The rate of degradation has also been increased with the increase of oxygen concentration for each sample. The variation of time effect on changing of GPC curve is also studied. GPC curves are changed preferably by the scission of longer chain in iPP, ePP1 and ePP2 with the increasing degradation time. The results reveal that the thermo-oxidative stability of isotactic polypropylene significantly depends upon the varying ethylene content incorporation.