Investigation of Miscibility of Linseed Oil Epoxy with Poly(vinyl alcohol)

Blending of two polymers in solution is a simple and cost effective technique to improve upon the physical and mechanical properties of the component polymers. Maximum synergism in the properties of the two polymers occurs when they are thermodynamically miscible. Poly(vinyl alcohol) (PVA) yields tough, flexible and water sensitive films. Linseed oil epoxy(LOE), a product from sustainable resource, used as a plasticizer and corrosion resistant coating, does not produce free standing film. A blend of PVA with LOE may yield films of good toughness and flexibility, and low water absorption if the two components are miscible with each other. Blends of PVA with LOE were prepared in weight ratios 80/20, 60/40, 40/60 and 20/80 through solution method by mixing in dimethyl sulphoxide. In the first instance, the miscibility the two components were investigated using the techniques of viscosity and ultrasonic measurements. The study revealed that the two components showed miscibility up to below 60 wt% PVA in the blend as at the composition LOE: PVA 40/60, phase inversion occurs. Above this composition, immiscibility is indicated; differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) delineates the above behavior in the solid phase.