The construction and verification of toughening model and formula of binary poly(lactic acid)-based TPV with co-continuous structure

Co-continuous morphologies have attracted substantial attention recently as it possesses a significant toughening effect. However, these investigations of toughening poly (lactic acid) (PLA) with co-continuous structure have been limited to simply qualitative explanation. The "reinforced concrete"-like structure is obviously different from the classic "sea-island" structure. Therefore, considering these toughening elements of the rubber content, interfacial cohesion strength and the strength of rubber, and referring to relevant theory models of reinforced concrete, we have established an original theoretical toughening model, at least semi-quantitatively, of the binary PLA-based thermoplastic vulcanizates (TPVs) with co-continuous structure based on PLA/natural rubber (NR) TPVs. Moreover, we reveal that the calibration model is suitable for PLA/nitrile butadiene rubber (NBR) and PLA/epoxidized natural rubber (ENR) systems, with a perfectly Adj. R-Square of 0.97 and 0.94, respectively. It should be mentioned that natural properties of NBR and ENR are significantly distinguished from NR. This study opens up a viable way to quantitatively understand the toughening mechanism with co-continuous structure.