New poly(lactic acid)-based nanocomposite films for food packaging applications

Evaluating the properties of starch/chitosan films with the incorporation of various nanoclays for use in food packaging

This study evaluates the properties of starch/chitosan films (SCF) produced via the casting method, incorporating 40 % (w/w) plasticizers (glycerol and sorbitol) and various concentrations (0, 3, 5, and 10 % (w/w)) of nanoclays (Cloisite 20A, Cloisite 30B, and K-10). The effects of each nanofiller on the films were thoroughly investigated. Films containing nanoclays exhibited reduced water solubility and enhanced thermal stability compared to films without nanofillers. A higher nanoclay concentration (10 % (w/w)) led to a reduction in the solubility of the starch/chitosan films, with a decrease of approximately 15 % relative to the SCF sample. Incorporating the three types of nanoclays improved tensile strength at break, particularly in samples with 3 % and 5 % (w/w) nanoclay content, achieving an approximate 68 % increase in tensile strength at break compared to the SCF sample. Atomic Force Microscopy (AFM) analysis revealed that increasing nanofiller content significantly heightened surface roughness. Films incorporating Cloisite 30B demonstrated lower surface roughness than those with Cloisite 20A and K-10 nanoclays, especially at concentrations of 3 % and 5 % (w/w), with a reduction of approximately 40 %. X-ray diffraction (XRD) analysis indicated superior interaction in films containing Cloisite 20A and 30B, while films with 10 % (w/w) K-10 exhibited a diffraction peak at 8.88°, suggesting inadequate incorporation. These findings align with the AFM analysis results for this film. Consequently, the integration of nanoclays improves the properties of starch/chitosan films, with formulations utilizing 20A and 30B nanoclays at 3 % and 5 % (w/w) showing the most promising potential for future applications in food packaging.