Noncovalent Hydrogen Bonds Tune the Mechanical Properties of Phosphoester Polyethylene Mimics.

Polyethylene mimics of semicrystalline polyphosphoesters (PPEs) with an adjustable amount of noncovalent cross-links were synthesized. Acyclic diene metathesis copolymerization of a phosphoric acid triester (M1) with a novel phosphoric acid diester monomer (M2) was achieved. PPEs with different co-monomer ratios and 0, 20, 40, and 100% of phosphodiester content were synthesized. The phosphodiester groups result in supramolecular interactions between the polymer chains, with the P–OH functionality as an H-bond donor and the P═O group as an H-bond acceptor. A library of unsaturated and saturated PPEs was prepared and analyzed in detail by NMR spectroscopy, size exclusion chromatography, differential scanning calorimetry, thermogravimetry, rheology, and stress–strain measurements. The introduction of the supramolecular cross-links into the aliphatic and hydrophobic PPEs showed a significant impact on the material properties: increased glass-transition and melting temperatures were observed and an increase in...