Amorphous phase-segregated copoly(ether)esterurethane thermoset networks with oligo(propylene glycol) and oligo[(rac-lactide)-co-glycolide] segments: synthesis and characterization

Completely amorphous copoly(ether)ester networks based on oligo(propylene glycol) and oligo[( rac -dilactide)- co -glycolide] segments were synthesized by crosslinking star-shaped hydroxyl-telechelic cooligomers using an aliphatic low-molecular weight diisocyanate. Two different network architectures were applied exhibiting differences in the phase-separation behavior. For networks from oligo(propylene glycol)- block -oligo[( rac -lactide)- co -glycolide] triols (G 3 OPG- bl -OLG) only one glass transition was obtained. However, networks from a mixture of oligo(propylene glycol) triols (G 3 OPG) and oligo[( rac -lactide)- co -glycolide] tetrols (P 4 OLG) with a ratio of components in a certain range show two glass transition temperatures ( T g ) being attributed to two segregated amorphous phases. In this way a wide spectrum of mechanical properties can be realized and adjusted to the requirements of a specific application.