Ultralong-Chain-Spaced Crystalline Poly(H-phosphonate)s and Poly(phenylphosphonate)s

Aliphatic poly(H-phosphonate)s were obtained by polyesterification of dimethyl H-phosphonate with bio-based long-chain diols. Nonadecane-1,19-diol, tricosane-1,23-diol, and octatetracontane-1,48-diol with dimethyl H-phosphonate yield the corresponding polyphosphoesters ( PPE19H, PPE23H, and PPE48H ) with molecular weights ( M n ) up to 4.3 × 10 4 g mol –1 . Postfunctionalization of these polymers via Hirao cross-coupling yields the selectively functionalized poly(H-phosphonate)s PPE19Ph, PPE23Ph, and PPE48Ph . DSC analysis revealed significantly enhanced crystallinities and melting points (up to T m = 110 °C) with increasing methylene sequence lengths. Hydrolytic degradation of polymer powder of poly-(H-phosphonate) occurred up to 95% in 2 days. The degradation rates decreased with increasing methylene sequence length. After postfunctionalization, degradation occurred only to a minimal extent over 3 months in basic and in acidic media.