Biodegradable plastic began being sparking interest in recent years with respect to solid waste accumulation and the eruption of oil crisis. Great efforts have been made in developing degradable materials without environment pollution to replace conventional petroleum-based plastics. Polylactide, a renewable, biodegradable and biocompatible thermoplastic, has been studied in this research. Halloysite nanotubes, a kind of natural occurring clay that has similar tubular structure as carbon nanotubes, were used to modify the properties of polylactide. Surface modification of halloysite was investigated as a means of improving the interfacial adhesion between halloysite and polymer matrix. Polylactide/halloysite nanocomposites have been prepared by melt blending in twin screw extrud...[ Read more ]

Biodegradable plastic began being sparking interest in recent years with respect to solid waste accumulation and the eruption of oil crisis. Great efforts have been made in developing degradable materials without environment pollution to replace conventional petroleum-based plastics. Polylactide, a renewable, biodegradable and biocompatible thermoplastic, has been studied in this research. Halloysite nanotubes, a kind of natural occurring clay that has similar tubular structure as carbon nanotubes, were used to modify the properties of polylactide. Surface modification of halloysite was investigated as a means of improving the interfacial adhesion between halloysite and polymer matrix. Polylactide/halloysite nanocomposites have been prepared by melt blending in twin screw extruder. And the morphology of the nanotubes was examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The thermal and mechanical properties of nanocomposites were characterized by Differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA), Dynamic mechanical analysis (DMA), tensile and three point bending test, notched impact test and single-edge-notched-bending (SENB) test. The results demonstrate that blending polylactide with 4w% halloysite nanotubes increased the fracture toughness K_IC by 32%, while the tensile and flexural properties have also been enhanced. The crystallization behavior of nanocomposites was studied by X-ray diffraction (XRD) and Differential scanning calorimetry (DSC). Moreover, the effect of annealing process has been investigated, which can increase crystallinity of nanocomposites and thus lead to better mechanical properties.