Enhanced Interfacial Compatibility Induced by Two-Step Reactive Extrusion: Toward Simultaneously Strengthening Mechanical and Foaming Properties of PEF/PGA Blends

Constructing a stable interfacial adhesion morphology of polymer blends remains an ongoing challenge in terms of the intrinsic instability of phase morphology. Herein, we obtained poly(ethylene 2,5-furandicarboxylate)/poly(glycolic acid) (PEF/PGA) blends with stable interface adhesion morphology and excellent physical properties by a two-step reactive blending method with the assistance of 2,2-bis(hydroxymethyl)-2,2,2-nitrilotriethanol (BIS-TRIS) and reactive elastomer (EGMA). Due to the formation of bonding points and branched/cross-linked structures, the interfacial morphology and melt strength of blends are significantly improved, leading to obviously enhanced foaming properties, thermostability, and mechanical properties. Specifically, when EGMA content was less than 20%, the blends still maintained tensile strength similar to that of neat PEF but with excellent toughness. Furthermore, all blend foams possess thin-walled cells with relatively uniform morphology, and the expansion ratio is more than 10-fold and shows greater compressive strength than commercial PET foams. Moreover, when the PEGMA foam was immersed in water for 2 weeks, the compression strength of the foam decreased by more than 70%, which makes it potentially useful in the field of temporary support.