DOI: https://doi.org/10.55373/mjchem.v25i3.244

Keywords: Palm oil; coating; cure rate; characterizations; film performance

Abstract

Increasing environmental concerns have stimulated the efforts to utilize renewable natural resources. Many previous researchers have reported the synthesis of alkyds from plant oils for coatings, that are relatively inexpensive and have good properties. In particular, soybean, castor, linseed and tall oils were very successfully used because they have high level of unsaturation enabling their alkyds to air-dry. The conventional method of alkyd synthesis is carried out at high temperature via the condensation of the oil with glycerol and dicarboxylic acid in xylene, and the use of organic solvent has made the process environmentally unfriendly. Palm oil is a major crop in Malaysia and consequently it is attractive to look into its use as raw material for industrial applications. However, it is a non-drying oil, and its alkyds are not capable of forming coherent film by air oxidation, consequently, palm oil alone cannot be used for coatings. This paper would present a number of selected polymeric materials made from palm oil derivatives. The first approach is to produce a water-reducible alkyd without organic solvent during synthesis. The resin is cross-linked by using a water-based melamine resin. The second approach is to incorporate palm oil alkyd into conventional acrylate resin. Thirdly the unsaturation of the alkyd could be increased through incorporating unsaturated dicarboxylic acid. The final alkyd has low molecular weight distribution and yet it could air-dry and even become UV-curable. Mechanical and physical properties of the coatings that have been characterized include curing rate, film hardness, adhesion, and chemical resistance.