Topology Controlled All‐(Meth)acrylic Thermoplastic Elastomers by Multi‐Functional Lewis Pairs‐Mediated Polymerization

Abstract

AbstractIt remains challenging to synthesize all‐(meth)acrylic triblock thermoplastic elastomers (TPEs), due to the drastically different reactivities between the acrylates and methacrylates and inevitable occurrence of side reactions during polymerization of acrylates. By taking advantage of the easy structural modulation features of N‐heterocyclic olefins (NHOs), we design and synthesize strong nucleophilic tetraphenylethylene‐based NHOs varying in the number (i.e. mono‐, dual‐ and tetra−) of initiating functional groups. Its combination with bulky organoaluminum [iBuAl(BHT)2] (BHT=bis(2,6‐di‐tBu‐4‐methylphenoxy)) constructs Lewis pair (LP) to realize the living polymerization of both acrylates and methacrylates, furnishing polyacrylates with ultrahigh molecular weight (Mn up to 2174 kg ⋅ mol−1) within 4 min. Moreover, these NHO‐based LPs enable us to not only realize the control over the polymers’ topology (i.e. linear and star), but also achieve triblock star copolymers in one‐step manner. Mechanical studies reveal that the star triblock TPEs exhibit better mechanical properties (elongation at break up to 1863 % and tensile strength up to 19.1 MPa) in comparison with the linear analogs. Moreover, the presence of tetraphenylethylene group in the NHOs entitled the triblock TPEs with excellent AIE properties in both solution and solid state.