Biodegradable poly(lactic acid) nanocomposites reinforced and toughened by carbon nanotubes/clay hybrids

Polylactic acid (PLA) is a biodegradable and biocompatible polyester derived from renewable resources like corn starch, presenting great potential in clinical applications like tissue engineering, implants and drug delivery systems. However, the intrinsic brittleness restricts its real applications. In this work, PLA nanocomposites were prepared by incorporating a small amount of carboxyl functionalized multi-walled carbon nanotubes (CNTs) and surface compatabilized montmorillonite (MMT) via technologies of freeze-drying and masterbatch-based melt blending. In the resulting nanocomposites, a well-distributed nano-filler network with microstructures of 1-D CNTs/2-D MMT platelets is formed favored by the enhanced interfacial interaction between the organic modified fillers with PLA matrix. Thanks to the well dispersed organic modified nanofillers, a large number of microcracks and extremely stretched PLA matrix are induced during tensile process, dissipating amounts of energy. As a result, the filler networks reinforce PLA with increment of 19% in modulus, remarkably increase by 13.8 times in toughness relative to PLA control without sacrificing strength. Thus, the PLA nanocomposites with excellent properties prepared through the facile and effective route possess broad prospect in biomedical applications.