Post-polymerization modification of poly(ethyl sorbate) leading to various alternating copolymers

Abstract

Eight novel alternating copolymers that are not accessible with general methodologies have been synthesized by the post-polymerization modification of poly(propylene-alt-allyl alcohol)100 (PPAA100). PPAA100 is obtained from a group transfer polymerization (GTP) made poly(ethyl sorbate)100 (PES100) by first hydrogenating its backbone double bonds followed by reducing its pendent esters to hydroxyl groups using lithium aluminum hydride. The post-polymerization modification of PPAA100 includes its condensation reactions with three reactive electrophiles, and its Mitsunobu reactions with five nucleophiles. The chemical transformations of the hydroxyl group to other functionalities have resulted in the eight unique head-to-head alternating copolymers which possess a fixed propylene structural unit and an allyl alcohol derived monomeric unit, such as allyl ester, sulfonate, phosphate, ether, halide, and imide. The chemical structures of the obtained polymers are verified by 1H and 13C NMR and FT-IR spectroscopies. Finally, the thermal properties of the resulting polymers with different side groups are studied.