Abstract:Antibacterial composite film was prepared by blending polyvinyl alcohol (PVA) and starch (ST) as raw materials and impatiens balsamina extract (IBE) as antibacterial agent. The morphology and structure of the composite film were characterized by Fourier Transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy and thermogravimetric analysis, and the mechanical, optical, barrier and antibacterial properties were tested and analyzed. The results showed that IBE was well combined with PVA/ST base film. The prepared PVA/ST/IBE antibacterial composite film had good antibacterial effect on Escherichia coli, Staphylococcus albus and Bacillus subtilis, and the antibacterial performance increased with the increase of IBE content. At the same time, PVA/ST/IBE film had good mechanical strength. The tensile strength of the composite film with 12.5 mL of IBE added reached 22.97±0.68 MPa, the elongation at break increased by 79.22% compared with the PVA/ST base film and transparency decreased by 11.90%; Antibacterial composite film had good oxygen barrier performance, the oxygen transmission coefficient was 1.771±0.196×10-12 cm3.cm/(cm2.s.Pa), had broad application prospects in environmental protection packaging, food preservation and other fields.