Manipulating the Filler Network Structure and Properties of Polylactide/Carbon Black Nanocomposites with the Aid of Stereocomplex Crystallites

Construction of various filler networks is an important issue for developing high-performance and multifunctional polymer nanocomposites. In this work, we report a facile and effective strategy to manipulate the filler network structure and properties of poly(L-lactide)/carbon black (PLLA/CB) nanocomposites with the aid of stereocomplex (SC) crystallization between PLLA matrix and small amounts of poly(D-lactide) (PDLA). The results reveal that the incorporation of only 1 wt % PDLA can facilitate the formation of CB network in PLLA/CB nanocomposites because SC crystallites induced enhancement in the melt viscosity of PLLA matrix could depress CB aggregation, finally leading to an evident decease in the electrical percolation threshold (phi(c)). However, with further increasing PDLA concentration to 10 wt %, the SC crystallites could organize into a dense network in the matrix and then serve as physical barrier for the networking of CB nanoparticles. As a result, the (PC of the nanocomposites increases sharply. The outstanding nucleating and strengthening effects of such SC crystallites on the nanocomposites are also highlighted. These findings suggest that the formation of SC crystallites could be a promising solution to create PLLA-based nanocomposites with tunable filler networks and properties.