Investigation of thermodynamically induced nanoparticle localization in Poly(vinylidene fluoride)/Poly(lactic acid) blends with surface-grafted carbon nanotubes

Physically anchoring multi-walled carbon nanotubes (MWCNT) onto the polymer blend interface has been extensively investigated, however, the tunable localization of polymer grafted MWCNT in immiscible polymer blends is seldom reported. Herein, poly(methyl methacrylate) (PMMA) grafted MWCNT (PMMA-g-MWCNT) were nondestructively prepared via the surface-initiated atom transfer radical polymerization. The compatibilization effects of PMMA-g-MWCNT on morphology and mechanical properties of blend composites are investigated. The results demonstrate that the fillers are distributed at the blend interface due to the high affinity between PMMA and PVDF. The interaction between PMMA and PLA changes the crystallinity of blends. Moreover, the surface modification of MWCNT enhances the interaction of filler and matrix, and the elongation at break is as high as 52 % for composites with 10 % PMMA-g-MWCNT. The fracture surface of specimen after tensile tests exhibits an obvious ductile transition with filler contents. This work systematically discussed the relationship between the PMMA-g-MWCNT distribution and the mechanical strength of composites, which provided a solid experimental foundation on the toughening mechanism of PMMA-g-MWCNT used as a compatibilizer for PVDF/PLA blends.