Fully renewable thermoplastic poly(ester urethane urea)s from bio-based diisocyanates

A series of fully renewable poly(ester urethane urea)s (PEUs) were synthesized from bio-based starting materials, e.g., the polyester diol, the diisocyanates including L-lysine diisocyanate (LDI) and isoidide diisocyanate (IIDI), the chain-extenders including 1,4-diaminobutane (bDA), diaminoisoidide (iDA) and di(aminobutyl) urea (b₂DA). It is found that the PEU based on the novel diisocyanate, IIDI, exhibits satisfactory thermal and mechanical properties. The LDI-based PEUs show less favorable thermal and mechanical properties than the IIDI-based counterpart, since the chemical structure of LDI is less regular than that of IIDI. However, by introducing a urea-containing dimeric diamine (b₂DA) instead of the monomeric diamines, the properties of the LDI-based PEU can be improved significantly. For instance, the flow temperature increases 100°C and the E-modulus also increases from 1 MPa to approximately 20 MPa. These fully renewable PEUs seem to be interesting materials and they can potentially be used in biomedical or packaging applications.