Mathematical Modeling and Optimization of Poly (Ethylene Vinyl Alcohol) Film Thickness and Ethylene Composition Based on I-Optimal Design

Understanding the factors and processes that influence the mechanical properties of plastic films is essential for numerous scientific and technological applications. Film thickness significantly affects these mechanical properties. EVOH (ethylene vinyl alcohol) is extensively used in the food packaging industry because of its exceptional air and moisture barrier properties. However, the mechanical properties of EVOH films are dependent on the thickness of the EVOH layer in multilayer films, which also affects the preservation capabilities of the food packages. In this research, mathematical models have been formulated to develop a functional relationship between the effect of EVOH films thickness and ethylene content, as independent variables, on mechanical properties including ultimate tensile strength, elongation at break, and elastic modulus, as dependent variables, using a Response Surface Methodology (RSM) through I-optimal design. The optimum conditions accrued with the EVOH films thickness of 0.03 and ethylene content of 48 mol%. Under the optimal conditions, the values of 25.178% for Elongation at Break, 3077.86 MPa for Elastic Modulus, and 97.44 MPa for tensile Strength were predicted. Analysis of variance (ANOVA) technique was employed to check the adequacy and significance of mathematical models and the model's regression coefficients were significant. The extruded EVOH films were further characterized using several characterization techniques such as scanning electron microscopy (SEM), FTIR, and mechanical testing.