Biobased Poly(ethylene terephthalate)/Poly(lactic acid) Blends Tailored with Epoxide Compatibilizers

To increase the biobased content of polyethylene terephthalate) (PET), up to 30 wt % poly(lactic acid) (PLA) was blended with PET using twin-screw compounding and injection molding processes. Multiftinctional epoxide compatibilizers including a chain extender and an impact toughening agent were used as blend modifiers to improve the poor mechanical properties of PET/PLA blends. The mechanical and thermodynamic performances were investigated along with the morphologicg features through scanning electron microscopy, atomic force microscopy, and interfacial tension determination. From Theological and differential scanning calorimetry results, it was observed that the molecular weight of both PET and PLA increased with compatibilizers because of epoxide reactions. The toughening agent, poly(ethylene-n-butylene-aaylate-co-glycidyl methacrylate) (EBA GMA), provided a 292% increase in impact strength over the blend but reduced modulus by 25%. In contrast, 0.7 phr addition of the chain e tende, poly(styrene-acrylic co 1 cid 1 methacrylate) (SA GMA)yielded comparable performance to that of neat PET without sacrificing the tensile and flexural properties. When both compatibilizers were present in the blend, the mechanical properties remained relatively unaltered or decreased with increasing EBA GMA content. The differences in mechanical performance observed were considered in relation to the strengthening mechanism of the 00 differing comPatibilizers and their effects on the miscibility of the blend.