1.1 BACKGROUND OF THE STUDY
Polymerization is one of the most industrial processes. Resins and emulsion are two main classes of polymer (Mark , 1964). The term “alkyd” was originally used by kienle in 1927 to describe the reaction products of polyhydric alcohols and polybasic acids. Extensive commercialization of special classes of polymeric esters which are not recognised as alkyds has forced a more limited definition. For example, among the polymeric esters which are alkyds by kienle’s definition are the unsaturated polyesters polymerised with styrene and the saturated polyesters reacted with isocyanites.
The term “alkyd” now tends to specify polyesters. Products composed of polyhydric alcohols, polybasic acids, and fatty mono basic acids. These materials (alkyds) are used chiefly in the coatings industry where they form non-volatile binder (or vehicle) in the manufacture of paints and varnishes. In this industry, the term alkyd, alkyd resin, and alkyd solution are used interchangeably (Sanler,1998).
The term “modified alkyd” is associated with chemical modifications that are carried out during alkyd resin preparation and that incorporate chemical agents of types other than those included in the definition. For example, if the alkyd polyesters formation takes place in the presence of vegetable oil, the polyester product will possess fatty acids residues on its chain and the resin is called oil modified alkyd resin. On the other hand, when no fatty acids are used, or when they are completely replaced by other types of acids, the product can be considered as “oil-free” alkyds (Patlon,1972).
Alkyd resins are by far the most important class of coating resins. It is estimated that alkyd resins contribute about 70% to the conventional binders used in surface coating is largely due to their unique properties such as film hardness, durability gloss and gloss retention, resistance to abrasion, impacted on them through modification with drying oil (Patlon, 1962).
Alkyd resins are used in both clear and pigmented, industrial and trade coating to protect and decorate a wide variety of substances. The industrial coatings or finishes generally are applied during the manufacturing process of the item which they cover. Often, they are specifically formulated to meet both conditions desired for their application and the endless use of the article of manufacture. The industrial finishes include primers and top coats for refrigerators, furniture and electrical equipment. In view of the development of these items and sectors, the positive growth is expected for paint industry (Waters, 1955).
Further, the paint industry envisages a future expansion in view of development in corrosion resistance coatings, expansion in housing activity and other industry uses. The demands of alkyd resin being an ingredient in paint, varnish and printing ink industry would be linked with the paint industry. There are many significant efforts that have been made to increase alkyd resin production. Many researchers have attempted to search the different sources for alkyd resin preparation. (Ikhuoria, 2004) studied enhancing the quality of alkyd resins using methyl esters of rubber seed oil in 2004.
A lot of alkyd resins were imported to Myanmar paint industries every year. In order to save foreign currency out flow, it is needed to produce alkyd resin in Myanmar. The oils that are mostly employed for alkyd resin synthesis are linseed oil, soya bean oil, dehydrated castor oil, fish oil and tall oil. Myanmar being rich in aquatic and terrestrial resources every state and division is pursuing the target of putting 500,000 acres under physic nut (castor oil) in the national development endeavours that are being carried out by the nation target (Mark,1964).
1.2 STATEMENT OF PROBLEM
Alkyd resin has been reported to have various uses in coating and paint industries. This has prompted this research work on the production of alkyd resin using the seed of water melon (Citrullus Lanatus).
1.3 OBJECTIVES OF THE STUDY
1. To extract oil from the seed of citrullus lanatus.
2. To evaluate the physical and chemical characteristics of the oil extracted from citrullus lanatus
3. To use the seed oil of citrullus lanatus to produce alkyd resin.
4. To determine the physicochemical properties of the alkyd resin produced from the oil of citrullus lanatus.