Homo(co)polymerization of bio-derived long alkyl chain methacrylate and methyl methacrylate using a readily accessible aminophosphine-based Lewis pair

Abstract

Lewis pair polymerization (LPP), emerging as an effective polymerization method, has been broadly investigated and applied in the synthesis of diverse polymers, e.g. poly(meth)acrylates, polyesters, polyethers etc. In the Lewis pair-mediated polymerization of conjugated polar monomers, Lewis bases having P–N bonds showed great promise in mediating controlled/living (co)polymerization of short alkyl acylates and short alkyl methacrylates. However, there have been far fewer experimental studies on long alkyl chain acrylates or methyl acrylates using LPP. Introduction of long alkyl side chains offers the opportunity to explore their influence on the parameters of the generated materials and tune the physical properties of copolymers to cater to society's demands. In this contribution, we synthesized the new aminophosphine LB bis(N,N-diethylamino)methylphosphine [(Et₂N)₂PMe] via varying the number of P–N bonds, and combined it with ⁱBu₃Al to form the Lewis pair (LP) for the (co)polymerization of methyl methacrylate (MMA) and bio-derived lauryl methacrylate (LMA). (Et₂N)₂PMe/ⁱBu₃Al showed both controlled polymerization of MMA and LMA at a monomer/(Et₂N)₂PMe molar ratio of 1600/1 or 700/1, respectively. Taking advantage of the linear chain end of PLMA, the block copolymer of PLMA-b-PMMA was synthesized via the sequential addition method and its physical properties were investigated.