Correlation between the secondary structure and hydrogen bonding in optically active polyurethane and its effect on infrared emissivity

Optically active polyurethanes (PUs) with different specific rotations were synthesized using a hydrogen transfer addition polymerization procedure with isocyanate-phenols of varying enantiomeric excess. The optical activities of the PUs were enhanced with an increase in the enantiomeric excess of the monomers. A helical secondary structure in the PUs with a more compact arrangement of the macromolecular backbones facilitated interchain hydrogen bonding, and the infrared emissivity of the corresponding polymers decreased. The results indicated that the level of order and number of hydrogen bonds in the macromolecule played significant roles in controlling the infrared emissivity.