Cassava (Manihot esculenta), also called manioc, tapioca or yuca, is one of the most important food crops in the humid tropics, being particularly suited to conditions of low nutrient availability and able to survive drought (Burrell, 2003). The plant grows to a height of 1 to 3 m and several roots may be found on each plant. Although cassava leaves are sometimes consumed, the major harvested organ is the tuber, which is actually a swollen root. The plant is propagated mostly from stem cuttings.
A major limitation of cassava production is the rapid post harvest deterioration of its roots which usually prevents their storage in the fresh state for more than a few days (Okezie and Kosikowski, 1982). Cassava ranks very high among crops that convert the greatest amount of solar energy into soluble carbohydrates per unit of area. Among the starchy staples, cassava gives a carbohydrate production which is about 40% higher than rice and 25% more than maize, with the result that cassava is the cheapest source of calories for both human nutrition and animal feeding.
Cassava Starch Essay Example
A typical composition of the cassava root is moisture (70%), starch (24%), fiber (2%), protein (1%) and other substances including minerals (3%) Compared to other crops, cassava excels under suboptimal conditions, offering the possibility of using marginal land to increase total agricultural production (Cock, 1982). Plant breeders, agronomists and recently molecular biologists have made substantial improvements in cassava yields during the last two decades. While, genetic characterization and mapping has revealed some insights into the molecular nature of cassava (Tonukari et al. 1997; Fregene et al. 003) Plastics are synthetic substances produced by chemical reactions. Almost all plastics are made from petroleum, except a few experimental resins derived from corn and other organic substances. Plastic has many properties which has made it a raw material of choice for Manufactures of plastic Bags and packing materials. Cost of production, lightweight, strength, easy process of manufacture, and availability are few of the properties. Man has simply not put the plastic to the right use/ or using it without taking proper care of other related norms of usage. The hazards plastics pose are numerous.
The land gets littered by plastic bag garbage presenting an ugly and unhygienic seen. The “Throw away culture” results in these bags finding their way in to the city drainage system, the resulting blockage cases inconvenience, difficult in maintaining the drainage with increased cost, creates unhygienic environment resulting in health hazard and spreading of water borne diseases. This littering also reduces rate of rain water percolating, resulting in lowering of already low water levels in our cities. The soil fertility deteriorates as the plastic bags form parts of manure remain in the soil for years.
People need alternative and effective components of plastic that is safe and biodegradable which will not harm and pollute the earth. Significance: This study is important to be able to help Mother Earth in reducing its pollutants and toxic or harmful wastes. Through this study, the researchers will be able to help other people, the animals and the environment. The researchers would like to stop plastic pollution and be part of the solution. Plastic bags and bottles, like all forms of plastic, create significant environmental and economic burdens.
They consume growing amounts of energy and other natural resources, degrading the environment in numerous ways. In addition to using up fossil fuels and other resources, plastic products create litter, hurt marine life, and threaten the basis of life on earth. There is over 45 million tons of plastics per year and nearly every piece of plastic ever made still exists today because of its long-life properties. Biodegradable plastics could be an effective solution to all of these problems. Biodegradable plastics are a much better choice than non biodegradable plastics because they are friendlier to the earth and the environment.
Biodegradable plastics break down faster, can be recycled easier and are non-toxic. With these characteristics of biodegradable plastics, we could help save lives and the environment as well and reduce the threat plastics give to marine life. Plastic, the wonder material that we use for everything, is perhaps the most harmful of this trash because it does not readily break down in nature but if it is biodegradable, these plastics break down faster so they have a much shorter effect on the earth, and they will degrade completely.
Normal plastics are manufactured using oil, and this process is very harmful to the environment by polluting the air and environment, but this is not the case with green biodegradable plastics. Using biodegradable plastics will minimize the effects that these products have on the earth, and help eliminate their waste much faster. Review of Related Literature: In the past few decades, there has been a marked advance in the development of biodegradable plastics from renewable resources, especially for those derived from starch-based materials.
The goal of this development is to obtain biodegradable plastics that perform as well as traditional plastics when in use and which completely biodegrade at disposal. Several starch-based plastics have been introduced into the market, and are used in some applications now. Starch foam is one of the major starch-based packaging materials. It is produced by extrusion or compression/explosion technology. This product has been developed as a replacement for polystyrene which is used to produce loose-fillers and other expanded items. Another type of starch-based plastics is produced by blending or mixing starch with synthetic polyester.
For this type of biodegradable plastics, granular starch can be directly blended with polymer, or its granular structure can be destructurized before being incorporated into the polymer matrix. The type of starch and synthetic polymer as well as their relative proportions in the blends influence the properties of the resulting plastics. The last group of starch-based plastics is polyesters that are produced from starch. The major starch-derived polyesters in the market now are polylactic acid and polyhydroxyalkanoate. Experimental studies have demonstrated that cassava starch could be used for making various types of packaging products.
As a major source of starch in tropical and subtropical regions, cassava is a promising raw material for the development of biodegradable plastics in these areas. Research has been done on HYPERLINK “http://en. wikipedia. org/wiki/Biodegradable” \t “_blank” \o “Biodegradable”biodegradable plastics that break down with exposure to sunlight (e. g. , HYPERLINK “http://en. wikipedia. org/wiki/Ultra-violet_radiation” \t “_blank” \o “Ultra-violet radiation”ultra-violet radiation), water or dampness, bacteria, enzymes, wind abrasion and some instances rodent pest or insect attack are also included as forms of HYPERLINK “http://en. ikipedia. org/wiki/Biodegradation” \t “_blank” \o “Biodegradation”biodegradation or HYPERLINK “http://en. wikipedia. org/wiki/Environmental_degradation” \t “_blank” \o “Environmental degradation”environmental degradation. It is clear some of these modes of degradation will only work if the plastic is exposed at the surface, while other modes will only be effective if certain conditions exist in landfill or composting systems. HYPERLINK “http://en. wikipedia. rg/wiki/Starch” \t “_blank” \o “Starch”Starch powder has been mixed with plastic as a filler to allow it to degrade more easily, but it still does not lead to complete breakdown of the plastic. Some researchers have actually HYPERLINK “http://en. wikipedia. org/wiki/Genetic_engineering” \t “_blank” \o “Genetic engineering”genetically engineered bacteria that synthesize a completely biodegradable plastic, but this material, such as HYPERLINK “http://en. wikipedia. org/wiki/Biopol” \t “_blank” \o “Biopol”Biopol, is expensive at present.
The diversity and ubiquity of plastic products substantially testify to the versatility of the special class of engineering materials known as polymers. However, the non-biodegradability of these petrochemical-based materials has been a source of environmental concerns and hence, the driving force in the search for ‘green’ alternatives for which starch remains the frontliner. Starch is a natural biopolymer consisting predominantly of two polymer types of glucose namely amylose and amylopectin.
The advantages of starch for plastic production include its renewability, good oxygen barrier in the dry state, abundance, low cost and biodegradability. The longstanding quest of developing starch-based biodegradable plastics has witnessed the use of different starches in many forms such as native granular starch, modified starch, plasticized starch and in blends with many synthetic polymers, both biodegradable and non-biodegradable, for the purpose of achieving cost effectiveness and biodegradation respectively.
In this regard, starch has been used as fillers in starch-filled polymer blends, thermoplastic starch (TPS) (produced from the combination of starch, plasticizer and thermomechanical energy), in the production of foamed starch and biodegradable synthetic polymer like polylactic acid (PLA) with varying results. However, most starch-based composites exhibit poor material properties such as tensile strength, yield strength, stiffness and elongation at break, and also poor moisture stability.
This therefore warranted scientific inquiries towards improving the properties of these promising starch-based biocomposites through starch modification, use of compatibilizers and reinforcements (both organic and inorganic), processing conditions, all in the hope of realizing renewable biodegradable substitutes for the conventional plastics. Definition of Terms Biodegradable – able to decompose naturally: made of substances that will decay relatively quickly as a result of the action of bacteria and break down into elements such as carbon that are recycled naturally Starch – a white, granular or powdery, odorless, tasteless and complex carbohydrate found chiefly in seeds, fruits, tubers, roots and stem pith of plants, notably in corn, potatoes, wheat, and rice; an important foodstuff and used otherwise especially in adhesives and as fillers and stiffeners for paper and textiles.
Plastics – the word plastic is derived from the words plasticus (Latin for “capable of molding”) and plastikos (Greek “to mold,” or “fit for molding”). Plastics are polymeric, moldable and synthetic materials which are derived from fossil fuels, such as oil, coal or natural gas. Plastics consist of organic (carbon-containing) long molecular chains that give them many of their unique properties. They can be made hard, flexible, strong, transparent, light and elastic. * Polymer – long-chain molecules that repeat their structures over and over *
Polyethylene Bags – the bags that you will see commonly used, such as plastic grocery bags, are made from petroleum byproducts, which is the root of most all of the environmental problems that they are the source of. Not only do they take substantially longer to break down or degrade, but as they do they release highly toxic chemicals. Resin – It is a hydrocarbon secretion of many HYPERLINK “http://en. wikipedia. org/wiki/Plant” \o “Plant”plants, particularly coniferous trees. It is valued for its chemical constituents and uses, such as varnishes and HYPERLINK “http://en. wikipedia. rg/wiki/Adhesive” \o “Adhesive”adhesives, as an important source of raw materials for organic synthesis, or for incense and perfume. * Polymer Methyl Ethyl Ketone Peroxide (MEKP) – The most popular type of hardener because of its economy and ease of use. * Polyester Resin – Polyester resins are the most commonly used matrix in the marine and composite industry. These resins are styrene-based, flammable and catalyzed when combined with Methyl Ethyl Ketone Peroxide(MEKP). Polyester resins are unsaturated resins formed by the reaction of dibasic organic acids and polyhydric alcohols.
Premix Polyester Resin R10-60 – It is a fast gel premix polyester resin used for wood, kapiz, and other lamination with cellophane, “Lumirror” or “Mylar” films. It is also used to make decorative jewels and flowers from ceramic molds, to make small coatings from polyethylene & silicone rubber molds, and to cast on intrinsic molds such as steel or bass frames. * Plastic Resin Glue – Plastic resins are made by heating hydrocarbons in what is known as the “cracking process. ” The goal here is to break down the larger molecules into ethylene, propylene, and other types of hydrocarbons.
The amount of ethylene produced depends on the cracking temperature. Once the cracking process has been completed, the compounds are formed into chains that are known as polymers. Different polymers are combined to make plastic resins that have the characteristics needed for different applications Methodology: A. Materials 2 Cassava Tubers 180 ml of Premix Polyester Resin 300 ml of Polymer MEKP Hardener 100 grams Petroleum Jelly 3 old shirts Measuring cup Grater Plastic Spoon Knife 3 Plastic Containers Chopping board B. Procedure Gather the Cassava Tubers. Ground and squeeze it to extract the starch.
Get hold of 240 grams of the starch and divide it into 3 equal parts: 80 grams in trial 1, trial 2 and trial 3. Place 60 ml of the plastic resin glue (Premix Polyester Resin) with 50 grams of flour catalyst for T1, 75 grams for T2 and 125 grams in T3. Mix and stir the components and pour it in the shirt with Petroleum Jelly and let it dry under the sun. To test its capacity to carry weight, use the plastic to carry objects. For its ability to hold water, put water inside the plastic. To test its tensile and bending properties, stretch the plastic as far as you can. Repeat steps 5-7 using T2 and T3.