One‐Pot Sequential Ring‐Opening Metathesis Polymerization and Acyclic Diene Metathesis Polymerization Synthesis of Unsaturated Block Polyphosphoesters

Abstract

A novel divergent approach is presented for the one‐pot synthesis of unsaturated block poly­phosphoester (PPE) structures by a sequential ring‐opening metathesis polymerization (ROMP) and acyclic diene metathesis (ADMET) polymerization. A linear functional PPE bearing one or two terminal acrylate groups is first prepared through the third generation Grubbs catalyst‐mediated ROMP of seven‐membered cyclic phosphate monomer, in the presence of a symmetrical multifunctional terminating agent or chain transfer agent. The functional PPE is then utilized as a selective macromolecular chain stopper in subsequent ADMET polymerization of phosphoester functional asymmetric α,ω‐diene monomer, yielding unsaturated block PPEs. The thermal properties of block PPEs are studied and their thermal degradation and flame‐retardant properties are evaluated. Furthermore, the prepared block PPEs can spontaneously self‐assemble in a selective solvent to form polymeric micelles, which are characterized in detail by dynamic light scattering, atom force microscopy, transmission electron microscopy, and scanning electron microscopy analyses. image