Oriented Polylactic Acid/Graphene Oxide Nanocomposites With High Mechanical And Thermal Properties

Oriented polylactic acid (PLA)/graphene oxide (GO) nanosheets tapes were prepared via uniaxial solid state drawing. The effect of various drawing conditions, including drawing ratio (DR), temperature (DT), and speed (DS) on mechanical, thermal, structural, and barrier properties were studied. Structural studies showed oriented structure for the drawn tapes with aligned polymer chains and GO nanosheets. Differential scanning calorimetry revealed improved glass transition temperature (T-g) and crystallinity (X-c) after drawing. In addition, T-g and X-c were increased more by increasing DR and DT. The highest T-g and X-c were achieved for 3/70/50 tape with values of 73 degrees C and %22, respectively. Higher thermal stabilities and enhanced barrier properties were achieved after drawing, especially at the higher DR. Finally, tensile testing revealed simultaneous improvement in stiffness and toughness due to strain hardening for all the drawn tapes. The strength and elastic modulus were increased after increasing DR, DS, and DT and reached the highest values of 149 MPa and 3.6 GPa for 3/70/50. Overall, the properties were controllable by the processing conditions.