Studies on epoxidised oil and its blend with polystyrene and poly(methyl methacrylate)

Abstract

Attempts have earlier been made to replace aromatic epoxies by renewable resource based vegetable oil epoxies. However the latter lack in toughness and strength. To improve these properties linseed oil epoxy was blended with polystyrene and poly(methyl methacrylate). The polyblends were prepared in varying proportion of oil epoxy and polystyrene/poly (methyl methacrylate), for investigation of their physical and mechanical characteristics with reference to their use in coatings. The blend formation was confirmed by DSC, FT-IR and solution tests. The epoxy equivalent, hydroxyl value, iodine value, viscosity, refractive index, and specific gravity of oil epoxy, oil epoxy -polystyrene blends and oil epoxy-poly (methyl methacrylate) blend were determined. Glass transition temperatures of linseed oil epoxy-polystyrene blends were found to occur in the range of 60-77.6°C and for the linseed oil epoxy-poly( methyl methacrylate) blends in the range of 75-82.4°C in the composition range investigated. Distinct shift in IR peaks of epoxy ring, ester group and hydroxyl group was observed in both the polyblends systems indicating electrostatic interaction between the constituents of the blends. Linseed oil epoxy was found to turn into rigid mass by the addition of these polymers to the extent of only 16.6% (<i>w/w</i>).Preliminary investigations also revealed higher toughness and rigidity in linseed oil epoxy-poly(methylmethacrylate) blends than in linseed oil epoxy polystyrene blends. Both the polyblends systems show solubility in various organic solvents.