Precise Sulfite Functionalization of Polyolefins via ADMET Polymerization.

Copolymers containing sulfite functionalities precisely placed between run lengths of 8, 14, and 20 methylene units were synthesized via ADMET with weight-average molecular weights up to 40 500 g/mol (PDI = 1.89). No such polymer structures have been observed previously. The primary polymer structures and precise nature were characterized by 1H NMR, 13C NMR, and IR spectroscopy. Thermal degradation temperatures up to 310 °C were observed through TGA, and melting points typical of similar unsaturated ADMET polymers were determined by DSC. X-ray scattering was used to compare the polymers to ADMET polyethylene (PE), and when the polymers have 20 carbons between sulfites, the functional groups self-assemble into layers. Higher carbon content incorporation leads to an increase in crystallinity and thermal stability for these polysulfites.