Metallocene‐catalyzed long‐chain branched <scp>POE</scp> : Kinetic mechanism and structure–property relationships

Abstract Polyolefin elastomer (POE) is widely used in photovoltaic encapsulation films but suffers from low melt strength, high extrusion energy consumption, and slow cross‐linking during melt processing. Incorporating long chain branches (LCBs) offers a promising solution for these issues. In this study, a trace amount of 1,9‐decadiene was incorporated into the ethylene/1‐octene copolymerization system catalyzed by a metallocene zirconium catalyst, significantly increasing the weight‐average molecular ( M w ) from 28.5 to 105.8 kDa. Rheological analyses confirmed enhanced zero‐shear viscosity and a pronounced decrease in viscosity with increasing frequency, indicating successful LCB formation. The long‐chain branch frequency reached 0.0667/1000C, as determined by triple‐detection gel permeation chromatography. A kinetic model was established, proposing that the insertion of 1,9‐decadiene generated macromonomers with pendant double bonds, which reinserted into ethylene‐terminated active sites and continued propagating to form LCBs. The strong consistency agreement between the experimental data and model predictions validated this mechanism.