Hyperbranched polyphosphoesters with reactive end groups synthesized via acyclic diene metathesis polymerization and their transformation to crosslinked nanoparticles

摘要

A novel hyperbranched polyphosphoester (HBPPE) was prepared by acyclic diene metathesis (ADMET) polymerization of an AB_2 monomer using the second-generation Hoveyda-Grubbs catalyst. IR analysis, gel permeation chromatography with multiangle laser light scattering, and NMR spectroscopy confirmed their controlled synthesis. The effect of the ADMET polymerization time in the thermal properties of HBPPEs was studied and their thermal degradation and flame-retardant properties were evaluated. These reactive HBPPEs were used to synthesize polyphosphoesters nanoparticles by intramolecular crosslinking of the end acrylate groups in dilute solution. The successful preparation of this new type of polymer nanoparticles was proven by NMR spectroscopy and gel permeation chromatography. The morphologies of nanostructures were investigated via dynamic light scattering, atom force microscopy, and transmission electron microscopy. The results revealed that the crosslinked nanoparticles, which have a comparatively uniform size, were stable and reproducible in organic solvents.