Preparation of carbon nanotubes/polylactic acid nanocomposites using a non-covalent method

The polymeric composites with four-armed star polylactic acid (PLA) immobilized on the surface of carbon nanotubes (CNTs) were constructed by a simple ultrasonic process using non-covalent method. The four-armed star polylactic acid was prepared by ring-opening polymerization of lactide using zinc p-tetraaminophenylporphyrin (ZnP) as initiator and stannous octoate as catalyst. Due to the strong π–π interactions between CNTs and zinc porphyrin of star PLA, the CNTs/PLA composites can be easily obtained while the intrinsic graphitic structure of CNTs is retained. The CNTs/PLA nanocomposite was studied via infrared spectrum (IR) and thermogravimetric (TG) analysis. UV–Vis and fluorescence demonstrate that the porphyrin probably strongly anchored on the side walls of the nanotubes. Optical studies further promise the non-covalent interactions. Meanwhile, morphology studies with and scanning electron microscope (SEM) show that CNTs are dispersed well in the polymer. This convenient non-covalent method may be useful for the preparation of CNTs–polymer hybrid without the destruction of the intrinsic graphitic structure of the pristine CNTs.