The bio-based thermoplastic vulcanizates (TPVs) composed of polylactic acid (PLA) and epoxidized natural rubber (ENR) was prepared by the dynamic vulcanization method induced by dicumyl peroxide (DCP), and a novel filler, bis(aminopropyl)-terminated polydimethylsiloxane (PDMS-NH 2 ), was added as the compatibilizer. The dynamic vulcanization reaction occurred first, and the PLA-g-ENR graft copolymer was formed at the interface of PLA and ENR.With the addition of appropriate amount of PDMS-NH 2 , the cross-linking of ENR was enhanced, and the size of PLA became smaller and more evenly dispersed. The prepared TPVs were found to have dual interfacial compatibilization networks. Mechanical characterization of this polymeric material containing a special structure is performed. TPV achieved the tensile strength at break of 12.8 MPa and elongation at break of 103%, revealing 103% and 329% higher than 6.3 MPa and 24% for the simple blend of ENR/PLA. Meanwhile, the elastic modulus of TPV increased to 352 MPa, which was 1.96 times that of the simple blend. As a result, ENR/PLA composites with high toughness and mechanical strength are achieved and the toughening mechanism and toughening factors were discussed.

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In the field of thermoplastic vulcanizate (TPV), experimental methods cannot quantify the relationship between the internal structure and performance of TPV, and are not conducive to the accurate design of TPV structure and performance, which is one of the problems to be solved in this field. In this study, a simple and effective two-dimensional micromechanical model was established based on the real microstructure of TPV by using the micromechanical method and the mechanical properties of TPV with different ethylene propylene diene monomer (EPDM) mass fractions were studied. The results show that with the increase of EPDM content, the maximum stress distribution area of TPV would change, the elastic modulus of TPV would gradually decrease, while the maximum stress of polypropylene (PP) phase would first decrease and then increase and strain corresponding to elastic–plastic change would also increase. The resilience of TPV increases with the increase of EPDM content and decreases with the increase of strain load. When the EPDM content is higher than 70%, the “S” bending deformation would occur at the thinnest part of PP matrix ligament.