Tuning mechanical properties of poly (vinyl alcohol) and its influence on different concentrations of epoxidized vegetable oils

Abstract

The proliferation in substituting traditional petrochemical-based polymer with biobased polymer blends to achieve sustainable materials with outstanding physical, mechanical properties, and biodegradability has been investigated. To emanate biodegradable films with better mechanical properties, the biobased blend of poly (vinyl alcohol) (PVA) was formed with three different oil epoxies namely Castor Oil Epoxy (COE), Mustard Oil Epoxy (MOE), and Til Oil Epoxy (TOE) with varying weight ratios. To examine the changes in physical and mechanical properties, various tests were performed such as tensile test, Shore-D hardness test, and sealability. The permeability of the samples has been studied by the water vapor transmission rate test. Solubility tests in various solvents impart an idea about the workable environment of the samples. Among different PVA/COE blends, the PVA/COE 80/20 blend showed the highest tensile strength while the highest hardness and elongation at break percentage was observed in PVA/COE 60/40 blend. In the case of PVA/MOE blends, PVA/MOE 40/60 blend displayed the best results for hardness and tensile strength while PVA/MOE 30/70 blend possessed the highest value for percentage elongation at break. Lastly, PVA/TOE 30/70 blend exhibited the highest value for tensile strength and percentage elongation at break. PVA/MOE 20/80 sample performed best in a basic environment. In nutshell, PVA modification with epoxide oil can improve the mechanical and biodegradable properties owing to the enhanced crosslinking and hydrophobic association. Ultimately, it was found that PVA/COE 80/20 blend has the best properties to be used as a film forming material as it has performed better or shown comparable properties in most of the tests. The resultant films can be widely used in the packaging industry for packing foodstuffs like fruit, vegetables, dairy products, etc., and also for drink packaging (beverage packaging).