Effects of ultrasound time on the properties of polyvinyl alcohol-based nanocomposite films

Preparation and evaluation of nanocomposite films have become prevalent in recent years. One of the most important methods for dispersing nanoparticles in polymers is the use of ultrasound radiation. Polyvinyl alcohol-montmorillonite (PVA-MMT) nanocomposite films were prepared via solvent casting method. The effects of different ultrasound times (0, 10, 20, 30, and 40 min) on the properties of nanocomposite films were evaluated in a completely randomized design (CRD) with five treatments and three replicates. The films were characterized by mechanical properties, opacity, water vapor permeability (WVP), and color. Fourier transform infrared (FTIR) and X-ray diffraction (XRD) were applied to investigate and prove the effects of ultrasound time. Results revealed that the ultrasound time significantly affected the characteristics of the films. XRD and FTIR results were in accordance with the effects of sonication time. The changing trends of PVA film properties due to increasing the sonication times were not similar. Sonication time did not have any significant effect on some traits like a*, WVP, L*, and yellowness index (YI), while it affected b*, tensile strength, and opacity significantly. Depending on the target of using nanocomposite films, appropriate time of sonication should be used.