Production of Alkyd Resin Using Water Melon Seed Oil (Citrullus Lanatus)
CHAPTER ONE
OBJECTIVES OF THE STUDY
- To extract oil from the seed of citrullus lanatus.
- To evaluate the physical and chemical characteristics of the oil extracted from citrullus lanatus
- To use the seed oil of citrullus lanatus to produce alkyd resin.
- To determine the physicochemical properties of the alkyd resin produced from the oil of citrullus lanatus
CHAPTER TWO
LITERATURE REVIEW
ORIGIN OF ALKYD RESIN
The condensation polymerization reaction by which polyhydric alcohols and polybasic acids form polymers with resinous characteristics has long been known. Berzelius in 1847 obtained a brittle, resinous polymer, the first polyester condensation product, from the reaction of tartaric acid with glycerol. An investigation of polyester resinous products was attempted in 1856 by Van BemmeLan, who prepared glycerides of succinic acid, tartaric acid and a mixture of succinic and benzoic acids. Additional studies on these types of polymers were made by Debris, Lawrenco, and furaro and Danesi. Ethylene glycol esters were prepared by Desplatz from D-tartaric acid, and Vorlander prepared maleate, fumarate, and succinate polyesters of ethylene glycol (Kirt,1964).
The brittle, glassy glycerol-phthalic anhydride polymer was first prepared by Watson smith. The initial stimulus towards detailed research on alkyd resins came from General Electric Company when in 1912,it commissioned investigations on these polymeric products because of their heat convertibility characteristics. Callahan fried bury, Arsem, Howell and Dawson of General Electric Laboratory Studied the glycerol-phthalic anhydride reactions intensively.
They pointed out that where part of the phthalic anhydride was replaced by a monobasic acid,such as oleic, the product were more flexible and had better solubility properties than glycerol phthalate.
The full potentials of alkyd resins were not realised until the development of glycerol phthalate containing unsaturated fatty acids. Kienle of General Electric is generally credited with making this significant contribution in 1927. Since then, alkyd resins have carved out a significant place in the protective coating industry(Solomon,1996)
CLASSIFICATION OF ALKYD RESINS:
In the coating industry, alkyd resins are generally classified into drying based on the kind of monobasic fatty acid present in the alkyd.
DRYING (OXIDIZING) ALKYDS:
In drying alkyds, the monobasic fatty acids contains unsaturated insufficient quantity to cause a thin film 25.2m of the alkyd to polymerization in the presence of oxygen at room temperature to give a coherent, solid film. Examples of vegetable drying oils used in the synthesis of drying alkyds are lung and linseed oils which contains large amounts of linolenic and linoleic acids (Gardon, 2001).
SEMI-DRYING ALKYDS:
The semi-drying alkyds have moderate levels of unsaturation oil the basic fatty acids and the drying process is slow when a thin film of the alkyd is exposedto the atmosphere (oxygen). Oils that are used for this purpose are soyabean and cotton seed oils among others.
NON-DRYING (NON-OXIDIZING) ALKYDS:
The amount of the unsaturated in the monobasic fatty acids is so low that little or no polymerization occurs with oxygen. The oils that fall into this category are castor and coconut oils. They contains considerable amounts of saturated acid residues such as stearic acid, palmitic acid. etc.
Alkyds are also classified into short, medium, long and very long alkyds based on the amount of oil and phthalic anhydride present in the alkyd.
CHAPTER THREE
MATERIALS AND METHODS
MATERIALS
Apparatus
Grinding machine, weighing balance, conical flasks, beaker, measuring cylinder, Heating mantle, water bath, Thermometer, spatula, stirring rod, magnetic stirrer, burette, pipette, density bottle.
Reagent
Distilled water, glycerol, phthalic anhydride, N-hexane, methanol, starch solution, sodium thiosulphate solution, potassium hydroxide.
Methods
Collection of sample
The seed of water melon used in this study were purchased from new market Enugu, Enugu state Nigeria. The seed were deshellded and dried under the Sun for one week and grounded into fine powder with a grinding machine
Procedure for Extraction of oil from the seed of water melon (Citrullus Lanatus).
200g of the grounded water melon seed were weighed into a plastic container with a cover. The weighed mass was soaked with n-hexane and the container was sealed to air tight. The mixture was allowed to stay for 24hours, with occasional agitation after which it was sieved with a sieve cloth. The filtrate was heated at 650c for 2hours so as to evaporate all the n-hexane in the oil.
CHAPTER FOUR
RESULTS AND DISCUSSION
DISCUSSION
The result of the % yield of seed oil of water melon is shown in table1; the result showed the percentage yield of the oil is 12.5%, showing that the seed contain small quantity of oil. The physiochemical of the oil is shown in table 2. The result of physiochemical properties of the seed oil of watermelon revealed that the oil is yellow in colour, specific gravity (s.g) is (0.90), free fatty acid 12.1 unit, saponification value (181mg of KOH\g of iodine value(68.63) g of iodine 100g of oil), refractive index at 40oC is 1.45 and the acid value 0.8(mgkm/g). The iodine value of the oil showed that the oil is drying oil since the iodine value is less than 100. The result of the percentage yield of the alkyd based on the oil is shown in table 3 and the alkyd resin has a percentage of yields of 80% based on the oil. The result of the physiochemical properties of the alkyd is shown in table 4. The alkyd has acid value of 5.0, it is clear, flexible adhesive, it has a surface dry of 2 hours and hard dry of 24 hours, these properties has shown that a high alkyd resin can be produced using the seed oil of watermelon.
CHAPTER FIVE
CONCLUSION AND RECOMMENDATION
CONCLUSION
Oil has been extracted from water melon seed using solvent extraction method. This physicochemical properties of the seed oil of water melon is similar to the Lin seed which is the major oil used in alkyd resin production. Two stages are involved in the alkyd resin production which are alcoholysis stage and esterification stage. The alcoholysis stage is catalysed with lead oxide and sodium hydroxide and the completion of alcoholsis stage is determined by dissolving the alkyd in methanol. The esterification stage is complete when the acid value of the alkyd resin reduces to 5.0. High quality alkyd resin can be prepared using the seed oil of water melon.
RECOMMENDATION
It is recommended that more research work should be carried out on the use of watermelon oil in the synthesis of industrial products, also means of recovery of the seed oil up to 90% should be encouraged because the oil is a drying oil.
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