The tensile behavior of the materials is also given in Fig. 1f.
It is clearly seen that the D65/35 shows a maximum elongation at break of about 200% without necking in our experiment, which is different from that of a simple PLA/NR blend system reported by Bitinis et al. [7].
They obtained a maximum elongation at break of about 200% with the addition of 10wt% of NR, and suggested that
the dispersed NR particles behaved as a stress concentrator, and the debonding in the initial stage of stretching
occurred at the particle-matrix interface due to the poor interfacial adhesion, resulting in the formation of a yield
point of PLA at which stable plastic deformation took place.
Obviously, no formation of necking during stretching for the D65/35 implies a different tensile mechanism.
Note that DCP was used as a crosslinking agent in our present system, which possibly initiated the PLA grafting onto NR
during melt-blending, resulting in improved interfacial compatibilization.
The interfacial adhesion between NR and PLA phases [26,27,30] may be one of the main reasons for the super toughness and substantially higher strain at break.