Synthesis and Chemical Recovery of Castor Oil-Based Poly(ester amides) with PE-Like Performance

Biobased closed-loop recyclable olefin-like materials are environmentally friendly and have promising application prospects. However, such materials are scarce, and especially the olefin-like materials developed so far are limited to polyester materials. Therefore, developing nonpolyester biobased olefin-like materials is of significant interest. In this study, a castor oil-based poly(ester amide) (PEA) with polyethylene-like properties and closed-loop recyclability was successfully prepared. The obtained PEA materials exhibit thermal and mechanical properties comparable to polyethylene and surpass those of previously reported linear poly(ester amide)s. Notably, PEA can be completely hydrolyzed to its precursors, N1,N10-bis(3-hydroxypropyl) decanediamide (DSE) and sebacic acid (SA), with yields of 73.1–75.8 and 92.8–96.2%, respectively. Further experiments demonstrated that repolymerization of recovered DSE and SA produced REPEA materials with mechanical properties equivalent to the original polymer. This study achieves closed-loop recycling for biobased linear nonpolyester materials, which offers a novel approach to design olefin-like sustainable materials.