Effect of carboxylate multi-walled carbon nanotubes on the performance of thermoplastic starch nanocomposites

A facile solution dispersion method is used to prepare high performance thermoplastic starch (TPS)/carboxylate multi-walled carbon nanotubes (CMWNTs) nanocomposites. Transmission electron microscopy demonstrates glycerol pretreatment can further restrain the agglomeration of CMWNTs. So the improved dispersion and hydrophilicity of CMWNTs are favorable to enhance the compatibility and homogeneity of TPS/CMWNTs nanocomposites. The improvements of CMWNTs content enhance both the pasting viscosity of cornstarch and thermal stability of TPS matrix proved by rapid visco analysis and thermogravimetric analysis, respectively. Scanning electron microscopy reveals that homogeneous TPS/CMWNTs nanocomposites can be achieved when CMWNTs content is below 1.5 wt%. CMWNTs can also form a perfect electric conductive network in TPS matrix at this concentration. However, higher CMWNTs content deteriorate the plasticization of cornstarch detected by Fourier transform infrared. Therefore, mechanical test shows that the residue cornstarch granules influence the load transfer from TPS matrix to the ultra-strong carbon nanotubes (CNTs).