Towards One-Pot Synthesis of Trimodal HDPE/UHMWPE In-Reactor Blends by CrOx/VOx/CpCr/SiO2 Tri-Metallic Catalysts

Trimetallic catalysis provides a potential route for the one-pot production of multimodal PE with balanced mechanical and processing properties. Herein, a series of CrO x /VO x /CpCr/SiO 2 trimetallic catalysts are constructed by grafting CrCp 2 onto a CrO x /VO x /SiO 2 with tunable CrCp 2 loadings and benchmarked against mono- and bimetallic catalysts. FT-IR spectroscopy confirmed successful CrCp 2 immobilization, and the catalyst containing 0.25 wt% CrCp 2 exhibited the highest productivity. Owing to the distinct H 2 sensitivities of the three active sites, both molecular weight (MW) and molecular weight distribution (MWD) can be efficiently regulated through CrCp 2 loading and H 2 partial pressure, enabling the synthesis of tri- or broad-modal PE in a single reactor. Compared with unimodal PE of comparable MW, the trimodal PE exhibited lower melt viscosity and an improved stiffness-toughness balance.