Bio-based Thermoplastic Polyhydroxyurethanes Synthesized from the Terpolymerization of a Dicarbonate and Two Diamines: Design, Rheology, and Application in Melt Blending

The terpolymerization of bio-based diglycerol dicarbonate (DGC) and Priamine 1074 is conducted with aminopropyl terminated polydimethylsiloxane (Mn = 1000 g/mol, PDMS) or 1,10-diaminodecane (DAD). Depending on DGC contents and PDMS/Priamine 1074 ratios, the resulting amorphous thermoplastic polyhydroxyurethanes (TPHUs) present random or block copolymer-like segmented structures. These TPHUs exhibit nanophase separation of small interdomain spacing (3–3.5 nm) mainly caused by DGC. As for DAD, it introduces crystallinity (8%) and chain ordering into the TPHU structure as observed from X-ray measurements. Some PDMS-based TPHUs are blended with PLA, and the blends are found to be partially miscible as they exhibit two Tg's, and their estimated relative energy differences (RED), calculated from Hoftyzer–Van Krevelen's group contribution method, are nearly unity. Based on the type of hydrogen bonding interactions and the extent of immiscibility (RED) of each of the blends, the TPHUs find potential applications as toughening agents and/or plasticizers for PLA.