Reaction mechanism and rheological properties of polypropylene irradiated under various atmospheres

Abstract It is well-known that the melt-strength properties of a polymer increases with molecular weight and with long chain branching due to the increase in the entanglement level. This study is a contribution for the understanding of the following points: — the role of branching, crosslinking and degradation on melt strength properties; — the mechanism and the kinetics of PP irradiation with time of irradiation and the importance of double bond formation. The results showed that degradation was the major reaction in the initial step of irradiation no matter the atmosphere and or antioxidant. However, double bond formation increased the production of branching and crosslinking reactions. Double bond formation had no effect on the crystallization kinetics, on the other hand, long chain branching had a marked effect on the crystallization temperature.