Chitosan/PVP/Modified Halloysite Composite Films with Enhanced Mechanical, Thermal, and Antimicrobial Properties

This research aimed to thoroughly evaluate the effect of adding poly(vinylpyrrolidone) (PVP) and modified halloysite nanotubes (HNT) and propolis extract (ppl) on the physical, thermal, and mechanical properties of chitosan (CS), polymer films to overcome the weaknesses of chitosan. The properties of prepared films were investigated using dynamic mechanical thermal analysis (DMTA), scanning electron microscopy (SEM), tensile testing, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and water vapor permeation (WVP) testing. The results revealed that adding 30 wt% PVP to chitosan, produced a single-phase mixture that increased the toughness of the blended film by about 320%, while greatly reducing the Young's modulus and tensile strength. The addition of the modified halloysite nanotube while improving the toughness of the polymer films by 230% also compensated for the loss of modulus and stiffness due to the addition of PVP and resulting in optimal mechanical properties. TGA results indicated the improved thermal behavior of CS by introducing the PVP and modified HNT. Meanwhile, the WVP results showed that the addition of 30 wt% of PVP and 3 wt% modified HNT decreased the water vapor permeability by about 52%. Although the incorporation of propolis extract enhances the antibacterial activity of the film, it leads to a slight reduction in thermal stability. Moreover, ppl appears to act as a toughening agent, contributing to a desirable balance among the mechanical properties and thereby optimizing the overall performance of the films.