Synthesis and characterization of segmented poly(ester-urethane)s (PEUs) containing carotenoids†
A series of twenty segmented poly(ester-urethane)s (PEUs) were synthesized, by the reaction of four different macrodiols derived from ε-caprolactone (CL) and 1,8-octanediol (Oct), 1,6-hexamethylene diisocyanate (HDI), and three different carotenoids, (3R,3′R,6′R)-lutein (1) obtained from a renewable source such as marigold (Tagetes erecta L.), (3R,3′S)-zeaxanthin (2) and (3R,3′S)-astaxanthin (3) obtained by partial synthesis from 1, as chain-extender agents. The mechanical properties of the PEUs showed evident plastic behavior. Some PEUs samples exhibited double segregation phases attributed to PCL (soft segment) and 1, 2, and 3/HDI (hard segment) detected by DSC. This work represents the first report of the use of carotenoids as chain extenders in the synthesis of PEUs.