Direct Synthesis of Polar-Functionalized Polyolefin Elastomers

Abstract

Polyolefin elastomers (POEs) are widely used for many applications including plastic toughening and encapsulating photovoltaic modules. The introduction of polar groups into POEs improves their compatibility and adhesion with polar components, but it is challenging to prepare high-molecular-weight polar-functionalized POEs (P-POEs) via copolymerization. Here, we report a silane protection strategy to enable the production of P-POEs (including an ethylene-based P-^EPOE and a propylene-based P-^PPOE) with widely tunable 1-octene incorporation ratios (7.4–19.8 mol %), appropriate polar monomer incorporation ratios (0.7–2.7 mol %), melting points (63.8–99.8 °C), and high molecular weights (up to 43.8×10⁴ g mol⁻¹). This approach involved the early transition metal-catalyzed terpolymerization of ethylene or propylene, 1-octene, and protected polar monomers. This silane protection strategy is superior to the previously widely practiced aluminum-based protection strategies in terms of polymerization activity, polymer molecular weight, comonomer incorporation, and product processibility. Most importantly, the P-POE products exhibited excellent mechanical properties and elasticity and served as high-performance compatibilizers and adhesives to enhance the functional applications of POEs.