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.
Introduction 1
1.1 Scope 3
1.2 Statement of problem 4
1.3 Objectives 4
1.4 Hypothesis 5
1.5 Limitations 5
Literature Review 7
2.1 Classification of adhesives 7
2.2 Molecular structure of starch 27
2.3 Forms of processed starch 29
Materials and method 32
3.1 Materials 32
3.1.2 Method 32
3.1.3 Extraction of starch from cassava 32
3.1.4 Production of adhesive from cassava 33
3.2 Test analysis 34
3.2.1 PH determination 34
3.2.2 Determination of tack time 35
3.2.3 Solid / moisture content determination 35
3.2.4 Wettablilty determination 36
3.2.5 Storage life determination 36
Results 37
4.1.0 PH values 37
4.1.1 Tack time determination 38
4.1.2 Solid and moisture contents 38
4.1.3 Wettability 38
4.1.4 Storage life 39
5.0 Discussion, conclusion and recommendations 40
5.1 Discussion 40
5.2 Conclusion 42
5.3 Recommendation 43
Reference 45
Appendix A - classification of adhesives
Appendix B - solid and moisture content
determination
Appendix C - standard glue samples and their Characteristics.
FIGURES
GLUCOSE MOLECULES
LINEAR AMYLASE STARCH MOLECULES
BRANCHED AMYL PECTIN STARCH MOLECULE
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.
It must be emphasized that starch-based adhesives are produced as a result of the ability of starch to gelatinize at a certain temperature. The gelatinizattion process involves hydrolysing of the starch to form gel, paste or solution. Starch based adhesive also include the degraded or converted starch such as dexxtin.
Adhesives generally found its applications in industries and starch-based applied in packaging labeling, book-binding, leatherworks etc. essentially adhesives especially the synthetic types found their application in components needed to make many products such as aircraft, corrugated cartons, plywoods, automobiles, envelopes, stamps, non woven fabrics etc.
The adhesive produced in this project will find its application mainly in paper bonding. Starch-based adhesives are cheap because, the raw materials are cheap because, the raw materials are cheap, readily available and give strong adhesion in low concentration in water. (De Bussy, 1972).
The scope of the project was concentrated on the extraction of starch from cassava, which was dried and later used to carry out several ranges of formulation aimed at obtaining adhesive. The adhesive produced were tested for solid/-moisture content, PH, tach time, wettability and washablitiy. It was also compared with the standard and existing types in the market.
As a result of the availability of metal on large volumes and the introduction of plastics, problems arises on how these diversity of materials could be joined. It has been observed that bonding by mechanical means such as welding, riverting, hailing etc does not give evenly stress distribution in the bonded area. Also use of mechanical method of thin to inhibited where the furthermore bonding by mechanical means involves removal of useful materials from the adherenal and also involves much distortion. The use of adhesives help to overcome these problems.
The objectives of this project is to produce adhesives locally from starch. This idea is a welcome one because of time has come when we should not depend solely on foreign technology for all we need, we should strive to achieve self, economic reliance by utilizing abundant raw materials. An adhesive industry sited in the rural areas where the raw materials is available will provide employment for unemployed youths and thus reduce rural urban migrations.
1. Can adhesive be produced from the hydrolysis of starch.
2. Can adhesive not be produced from the hydrolysis of starch.
The starch-based adhesive that will be produced will it compare with the market adhesives.
The starch-based adhesive that will be produced will it not compare with the market adhesive?
Most problems encountered during the research work, limited the efficiency of this research, these include;
Text Book- most texts required for complete research on the topic were not available and this limited the research work.
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