Toward strong and super-toughened PLA via incorporating a novel fully bio-based copolyester containing cyclic sugar

Blending polylactide (PLA) with flexible polymers is usually capable of reducing its inherent brittleness, which, however, is accompanied with a substantial decrease in tensile strength. Here, considering the integration of flexibility and rigidity, 1,4-butanediol and dodecanedioic acid with flexible alkyl chains as well as isosorbide with a rigid cyclic sugar structure is used to synthesize a new bio-based copolyester. By virtue of interfacial compatibilization between PLA and the copolyester via dicumyl peroxide-induced dynamic vulcanization, well balanced mechanical properties are achieved for resulting blends, that is, elongation at break and notched impact strength are increased to 298.4% and 578.0 J/m that represent 37- and 24-fold increases, while tensile strength maintains at 59.5 MPa that decreases by only ~15% compared with that of neat PLA. Massive shear yielding of PLA matrix triggered by internal micro-voids accounts for the toughening mechanism. Given the high mechanical strength and supertoughness, the PLA-based materials have potential applications in different areas.