Simply Prepared Dual-Initiating Bis-Phosphonium Ylide-Based Lewis Pairs for Efficient Synthesis of Alkyl (Meth)acrylates (Co)polymers

The development of simply prepared catalysts for efficient and controlled polymerization is an important research challenge in polymer chemistry. Here, six newly designed dual-initiating bis-phosphonium ylide Lewis bases (LBs) with different linker lengths were prepared in a one-step process. When combined with organoaluminum, these LBs enable rapid and living polymerization of five alkyl (meth)acrylates, including methyl methacrylate (MMA), ethyl methacrylate (EMA), benzyl methacrylate (BnMA), n-butyl acrylate (nBA), and 2-ethylhexyl acrylate (EHA). Consequently, polymers with predictable molecular weights (Mn up to 155.1 kg/mol) and small Đ values (as low as 1.08) can be synthesized. By integrating the unique compounded sequence control (CSC) strategy of Lewis pair polymerization (LPP) and dual-initiating character of these bis-phosphonium ylide LBs, undecablock copolymers of different monomers were prepared through three sequential monomer mixture feeding while maintaining excellent controllability over polymer structures as demonstrated by gel permeation chromatography (GPC) and diffusion ordered spectroscopy (DOSY) analyses. Furthermore, a series of all-acrylic-based thermoplastic elastomers (TPEs) with different hard and soft segments were also synthesized in one-step, and the copolymer structures and glass transition temperature (Tg) effects on the mechanical properties of the TPEs were investigated. Hence, the aforementioned outcomes underscore the efficiency and robust capability of our newly developed bis-phosphonium ylide-based LPP strategy in polymer synthesis.