Mechanical and Barrier Properties of LLDPE/Chitosan Blown Films for Packaging

The blends of linear low-density polyethylene and chitosan were prepared by using a two-step melt-compounding process and then were made into blown films for packaging. LLDPE-g-MAH was used as compatilizer to enhance the dispersing effect of chitosan in the matrix. Fourier transform infrared spectra and scanning electron microscope images of the blown films confirmed that there were new amide bonds formed between chitosan and LLDPE-g-MAH. The mechanical and barrier properties of the LLDPE/chitosan blown films were investigated. The result indicated that the breaking strength and elongation decreased as the chitosan content increased. In addition, the water vapour permeability of the blend films could be improved up to 200% with the increment of chitosan content, and the oxygen permeability decreased about 20% compared with the films without chitosan. It was found that LLDPE-g-MAH had obvious effects on the mechanical properties and oxygen permeability apart from the water vapour resistance. Copyright © 2015 John Wiley & Sons, Ltd.