Toughening Brittle Poly(ethylene Furanoate) with Linear Low-Density Polyethylene via Interface Modulation Using Reactive Compatibilizers

Among various biorenewable polymers, poly(2,5-ethylene furandicarboxylate) (PEF) has a large potential to replace fossil-based poly(ethylene terephthalate) (PET) for different applications. However, despite showing better gas barrier properties compared to PET, the inferior mechanical properties of PEF hinder its potential applications. This study reports the toughening of PEF with linear low-density polyethylene (PE) via melt blending by reactive compatibilization at the polymer-polymer interface and benchmarking against similar PET/PE blends. The wettability and spreading coefficient predictions indicate a preferable location of the ternary component (styrene-ethylene/butylene-styrene-graft-maleic anhydride (SEBS-<i>g</i>-MA) or polyethylene-graft-maleic anhydride (PE-<i>g</i>-MA)) along the PEF/PE interface. The interfacial ternary component (concentration and type) exhibited substantial effects on the PEF/PE morphology, altering it from a very coarse incompatible structure to a dispersed morphology for SEBS-<i>g</i>-MA, and fibrillar and cocontinuous morphologies for PE-<i>g</i>-MA. The morphology change in the blends is attributed to reactive compatibilization between the anhydride group of the compatibilizer and the hydroxyl end-group in PEF at the interface. The SEBS-<i>g</i>-MA compatibilized blends exhibited enhanced ductility, as the elongation at break substantially increased with increasing compatibilizer loading, resulting in an 800% increment in the elongation at break and 250% in the tensile toughness compared to those of the neat PEF. These improvements may open new applications of biobased PEF flexible materials for the packaging industry.