Crosslinked bicontinuous biobased polylactide/natural rubber materials: Super toughness, “net-like”-structure of NR phase and excellent interfacial adhesion

Polylactide (PLA) and natural rubber (NR) are two major renewable resources in the polymer materials field. However, their blend has not yet met engineering needs, largely because of a lack of interfacial adhesion between the continuous PLA phase and dispersed NR droplets. To address this issue, we have designed a novel super toughened biobased PLA/NR blend prepared by peroxide-induced dynamic vulcanization, in which the cross-linked NR phase has a specific continuous “net-like” structure. A sharp brittle-ductile transition occurred in the blend with 35 wt% NR, showing impact strength of 58.3 kJ/m2, approximately 21 times that of the neat PLA. The peroxide initiated reactive compatibilization at the interface between PLA and NR. The toughening mechanism and deformation of the crosslinked “net-like” NR phase during stretching are discussed. Our results provide evidence of a continuous “net-like” NR located in the PLA matrix with good interfacial adhesion, which potentially enhances the mechanical properties of the material.