Effect of Plasticizer Concentration on the Characteristics of Polyvinyl Alcohol-Based Films

This research focuses on the fabrication and characterization of polyvinyl alcohol (PVA) films incorporating varying concentrations (0, 5, 10, 15 wt.%) of triacetin (TRI) as a bioplasticizer. The effects of TRI on the physical, surface and structural, dynamic mechanical and barrier properties of polyvinyl alcohol (PVA) films were systematically investigated. The physical characteristics such as thickness and density of the films were influenced by TRI content. Scanning electron microscopy (SEM) analysis revealed notable changes in surface morphology with increasing TRI concentration, while water contact angle measurements indicated altered wettability. Fourier transform infrared (FTIR) spectroscopy confirmed molecular interactions between TRI and PVA matrix. X-ray diffraction (XRD) analysis showed a reduction in crystallinity upon the addition of TRI. Moreover, dynamic mechanical analysis (DMA) revealed variations in storage modulus, loss modulus, and glass transition temperature (Tg), indicating improved flexibility and processability of the plasticized films. Gas barrier properties exhibited a concentration-dependent behavior; the addition of 5 wt.% TRI enhanced the barrier performance against oxygen and carbon dioxide, whereas higher plasticizer contents (notably 15 wt.%) resulted in increased gas permeability. Therefore, 5 wt.% TRI was determined as the optimum content for packaging applications.