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

摘要

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 ,-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.