Starch/multi-walled carbon nanotubes composites with improved mechanical properties

In this work, novel starch based nanocomposites containing very small quantities of multi-walled carbon nanotubes (MWCNTs) (0.027 wt% and 0.055 wt%) were developed. These materials exhibited highly improved tensile and impact properties as a consequence of wrapping the MWCNTs with a starch–iodine complex composed by the same starch of the matrix. Thus, good dispersion of the filler in the matrix and excellent adhesion between phases (as shown in FE-SEM micrographs) were achieved. Increments up to almost 70% in stiffness and 35% in ultimate tensile strength, keeping deformations higher than 80% without break were found. Therefore, tensile toughness also increased up to ∼50%. Enhancements of up to ∼100% in biaxial impact parameters (thickness related perforation energy and disc maximum strength values) were also observed. The significant improvements in all uniaxial tensile and biaxial impact properties obtained for such significantly low contents of filler, as a result of the type of functionalization used, have not been already reported in the literature and point out these biodegradable composites as a very appealing alternative to traditional materials for different applications.