Physical Properties of Maleated Poly(lactic acid) Composites Containing Different Functionalized Multiwalled Carbon Nanotubes

Abstract

In the current study, maleic anhydride-grafted poly(lactic acid) (MA-g-PLA) was prepared by using a reactive blending method to improve interfacial interaction and compatibilization in PLA/functionalized multiwalled carbon nanotube nanocomposites. Concentrations of maleic anhydride and initiator were varied at 3, 5 wt% and 0-0.7 wt%, respectively. The maleation content was determined by using a titration method, in which MA-g-PLA containing the optimum degree of grafting was subsequently chosen to prepare the nanocomposites containing hydroxyl and carboxylic functionalized multiwalled carbon nanotubes at various contents (0-5 wt%) and compared with the ones prepared with non-functionalized type. Dispersion morphology, thermal and mechanical properties of the resultant nanocomposites were investigated by means of transmission electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and tensile measurement. It was shown that the compatibility between the nanotubes and MA-g-PLA was improved where the functionalized nanotubes exhibited a better dispersion and mechanical property than the nonfunctionalized nanotubes. With increasing concentration of carbon nanotubes, tensile strength and Young's modulus of the nanocomposites were correspondingly enhanced, in which at 5 wt% addition yielded the highest values at 90 MPa and 10 GPa, respectively.