Starch was extracted from cassava tubers using the wet extraction method. Various formulations were developed and hence optimum quality was obtained. The formulations were produced by gelatinization process and were based on varying the quality of the additives used.
The test carried out on the formulations include:- determination of the PH. The PH of the formulated adhesive is 6.8 while is fairly comparable. Solid/moisture content of the formulations are 19.4% and 82.2% respectively and that of standard is 15-30% and 65-85% respectively.
The tack time of the formulated adhesive was 16 minutes which is also comparable to the standard which is 15 minutes. Shelf life of the formulated adhesives has exceeded more than two months and it is still suitable showing that it could be equal to the shelf life of market.
Finally the wettablility of the formulations were comparable with the wettability of market adhesives.
Essentially all adhesive can be classified as either organic or inorganic material and each of these groups may be further subdivided.
Some of these products are not new for example, the naturally occurring organic adhesives have been in use ever since, the first shellfish attached itself to a rock. And there is a good evidence o the ancient Egyptians using inorganic material to bond furniture. The development of adhesives has continued over the centuries to meet the requirements of various civilizations, but it was not until the industrial revolutioin that demands were made for major advances in adhesive technology. As a result of the availability of metal in large volume and the introduction of plastics, problem arises-including that of how to join this diversity of materials. In a quest to find the solutions to these problem, lead to the current development in adhesive technology. (lees, 1989).
Adhesives exist in a variety of forms, liquid paste, film, powder, granules and in solid forms. Materials being fastened together by adhesives are called substrates or adherends. For an adhesive to fasten a material it must displace sir and other contaminants on the surface of the material, this phenomenon is known as wetting while the resulting assembly is the adhesive joint. Compositions of adhesives include binders such as starch, solvent which is the media in which the binders are dispersed to become a spreadable liquid, gelatinzers fillers, thickeners and preservatives to control microbial activities.
Two types of adhesives exists, these are organic adhesives. The organic adhesive is subdivided into natural and synthetic adhesives. The natural adhesives include animal gllue, casein glue, starch e.t.c. while the synthetic adhesives include the thermoplaswtic resins, polyesters, urethanes e.t.c.
The inorganic type are the cement, soder and silicates. (Lees 1989).
A study of starch and its derivatives shows that starch is the principal water dispersible natural polymer used industrially as adhesives. Chemically starch is a carbohydrate having the empirical formular (c6H10O5)n. it is a soft white powder second in abundance only to cellullose. It occurs particularly in grains, example maize, sorghum etc, in tubers example cassava, yam and in stem example cassava, yam and
In stem example sago palm.
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