Synthesis of high thermal stability Polypropylene copolymers with pyrrole functionality

Functionalization of polyolefins has been proven to be a promising way to fine-tune their properties, among which, improved thermal stability is crucial for high performance in end-use applications. However, it still remains in academia, as some important issues still need to be resolved for this methodology to move towards industrial scale-up, the most important of them being the development of one-step processes. This work focuses specifically on the development of a single-step functionalization route for the synthesis of high thermal and thermo-oxidative stability polypropylenes. The synthesis of Polypropylene (PP) bearing N-alkyl groups by copolymerization via metallocene catalysis is studied. The copolymers are found to exhibit high thermooxidative stability, whose origin appears to be based, not only on the radical scavenging activity of N-alkyl moieties, but also on the associated crosslinking that takes place under processing conditions. Some exploratory results from a solid-state 13CNMR analysis provide support to a radical mechanism, involving coupling between benzyl-like pyrrolyl species.