Effect of polyethylene internal structure on antibacterial properties of nanosilver composites

The antibacterial properties of nanosilver polyethylene packaging play a pivotal role in the fields of food packaging. The difference in the crystalline structure of the materials will affect the migration of nanosilver in polyethylene, thereby affecting the antibacterial rate. A series of nanosilver/polyolefin composite films were prepared by melt blending. The investigation included scanning electron microscope-energy-dispersed analysis of X-ray, melt index, thermal properties, small-angle laser scattering, small-angle X-ray scattering, and optical properties, as well as antimicrobial activity against Escherichia coli. The results indicate that the material with a higher melt index has better fluidity and the higher antibacterial rate. Moreover, nanosilver is uniformly dispersed in the substrate. Nanosilver can increase the long period without affecting the crystalline region. For these neat materials, HDPE has the thickest lamellae, which is easier to inhibit the migration of silver, and has the lowest antibacterial rate. Meanwhile, materials with low crystallinity exhibited high antibacterial properties. The crystallinity of the composites was slightly increased by the induction of silver nanoparticles. The optical properties show that nanosilver can reduce the size of spherulites and improve the optical properties of the composites. The research has guiding significance for the commercial production of polyethylene antibacterial packaging materials.