Study On The Preparation And Properties Of Poly(Lactic Acid)/GO-ZnO Nanocomposite Films

In this paper, graphene oxide loaded with ZnO nanoparticles (GO-ZnO) was prepared. GO-ZnO with a certain loading amount of ZnO was selected as nanofiller and mixed with poly(lactic acid) (PLA) by solution-blending method. PLA/GO-ZnO nanocomposites fims plasticized by poly(ethylene glycol) of different molecular weight were also prepared. This study focused on the mechanical properties, heat resistance properties, anti-UV and antibacterial properties of the nanocomposite films.A rapid chemical precipitation method was employed to prepare the GO-ZnO nanohybrids with different contents of ZnO. The results of TEM, FES EM and XPS showed that the formation of coordination bonds between GO and ZnO can effectively prevent the ZnO nanoparticles from agglomeration. ZnO nanoparticles uniformly grew on the surfece of the exfoliated GO sheet during the precipitation process, and the particle size is about 15-30nm. TG, UV-Vis, and contact angle tests showed that ZnO nanoparticles can promote the thermal decomposition of GO, and GO-ZnO nanohybrids can effectively absorb UV light, but possessed worse hydrophily compared with pure GO.Using chloroform as solvent, PLA/GO-ZnO nanocomposite films were prepared through a solution-blending method. SEM and XRD tests suggested that GO-ZnO sheets were dispersed homogeneously in the PLA matrix and had no effect on the crystal form. The results from tensile, DMA and TG showed that the tensile strength and storage modulus of the nanocomposite films was significantly improved, but the heat resistance properties declined compared with pure PLA. In addition, the PLA/GO-ZnO films revealed a strong UV light shielding efficiency and antimicrobial ability. With 0.5wt% GO-ZnO, the antibacterial rate(R) of the film for S. aureus was 99.8% and the value for E. coli was 98.5% under light irradiation.PLA/GO-ZnO nanocomposite films plasticized by poly(ethylene glycol)200 (PEG200) and poly(ethylene glycol) 1000 (PEG1000) were prepared to improve the flexibility. The results showed that the elongation at break increased evidently and the tensile strength decreased with increasing PEG content UV-Vis and antibacterial tests showed that plasticized PLA/GO-ZnO nanocomposite films maintained the strong UV light shielding efficiency and revealed significant antibacterial ability with 15 wt% PEG.