Background of the Study Starch is a linear polymer (polysaccaride) made up of repeating glucose groups linked by glucosidic linkages in the 1-4 carbon positions. The length of the starch chains will vary with plant source but in general the average length is between 500 and 2 000 glucose units. There are two major molecules in starch - amylose and amylopectin. The alpha linkage of amylose starch allows it to be flexible and digestible.
Starch-based biodegradable plastics may have starch contents ranging from 10% to greater than 90%.Starch based polymers can be based on crops such as corn (maize), wheat or potatoes. Starch content needs to exceed 60% before significant material breakdown occurs. As the starch content is increased, the polymer composites become more biodegradable and leave less recalcitrant residues. Often, starch-based polymers are blended with high-performance polymers (e.
g. aliphatic polyesters and polyvinyl alcohols) to achieve the necessary performance properties for different applications. Starch may offer a substitute for petroleum based plastics.Starch is a renewable degradable carbohydrate biopolymer that can be purified from various sources by environmentally sound processes. Starch, by itself, has severe limitation due to its water solubility. Articles made from starch will swell and deform upon exposure to moisture.
To improve some of the properties, starch is often blended with hydrophobic polymers during the past decades by a number of researchers with petroleum polymers to increase biodegradability, and reduce the usage of petroleum polymer.Biodegradation of starch based polymers is a result of enzymatic attack at the glucosidic linkages between the sugar groups leading to a reduction in chain length and the splitting off of sugar units (monosaccharides, disaccharides and oligosaccharides) that are readily utilised in biochemical pathways. Biodegradable waste is an important substance due to its links with global warming. When it is disposed of in landfills, it breaks down under uncontrolled anaerobic conditions.
This produces landfill gas which, if not harnessed, escapes into the atmosphere.Landfill gas contains methane, a more potent greenhouse gas than carbon dioxide. This can cause harmful effects on the environment. Substances that are broken down by biological processes are said to be biodegradable.
Glycerin is a viscid, colourless liquid of sp. gr. r 265 at 15° C. , possessing a somewhat sweet taste; below o° C. it solidifies to a white crystalline mass, which melts at 17° C. When heated alone it partially volatilizes, but the greater part decomposes; under a pressure of 12 mm.
of mercury it boils at 170° C. In an atmosphere of steam it distils without decomposition under ordinary barometric pressure.It dissolves readily in water and alcohol in all proportions, but is insoluble in ether. It possesses considerable solvent powers, whence it is employed for numerous purposes in pharmacy and the arts.
Its viscid character, and its non-liability to dry and harden by exposure to air, also fit it for various other uses, such as lubrication, &c. , whilst its peculiar physical characters, enabling it to blend with either aqueous or oily matters under certain circumstances, render it a useful ingredient in a large number of products of varied kinds.Objectives General Objective: To test the cornstarch and glycerin in providing a biodegradable polymer. Specific Objective: To determine which of the treatments performed in the experimentation is more applicable in making Biodegradable polymers.
Significance of the Study This study was conducted in order to make something more effective and useful to the world. Today, our world is undergoing and experiencing the global warming. Global warming and climate change are aspects of our environment that cannot be easily or quickly discounted.Many factions still strongly feel that the changes our Earth is seeing are the result of a natural climatic adjustment. Regardless of one’s perspective the effects of global warming are a quantifiable set of environmental results that are in addition to any normal changes in climate. That is why the effects of global warming have catastrophic potential.
Global warming may well be the straw that breaks the camel’s back. It could turn out to be the difference between a category three hurricane and a category four. Global warming as caused by greenhouse gas emissions can lead us to a definite imbalance of nature.Scope and Limitations This study is limited only to the experimentation of the application of Corn Starch and glycerin in making biodegradable polymers. Theoretical and Conceptual Framework Pure starch is a white, tasteless and odorless powder that is insoluble in cold water or alcohol.
It consists of two types of molecules: the linear and helical amylose and the branched amylopectin. Depending on the plant, starch generally contains 20 to 25% amylose and 75 to 80% amylopectin. Glycogen, the glucose store of animals, is a more branched version of amylopectin.Starch is processed to produce many of the sugars in processed foods. When dissolved in warm water, it can be used as a thickening, stiffening or gluing agent, giving wheatpaste. Independent Dependent A Review on Related Literature Biodegradable bioplastics are used for disposable items, such as packaging and catering items (crockery, cutlery, pots, bowls, and straws).
Biodegradable bioplastics are also often used for organic waste bags, where they can be composted together with the food or green waste.Some trays and containers for fruit, vegetables, eggs and meat, bottles for soft drinks and dairy products and blister foils for fruit and vegetables are manufactured from bioplastics. Nondisposable applications include mobile phone casings, carpet fibres, and car interiors, fuel line and plastic pipe applications, and new electroactive bioplastics are being developed that can be used to carry electrical current. In these areas, the goal is not biodegradability, but to create items from sustainable resources.
According to Gross and Kalra (2003) Biodegradable polymers are designed to degrade upon disposal by the action of living organisms.Extraordinary progress has been made in the development of practical processes and products from polymers such as starch, cellulose, and lactic acid. The need to create alternative biodegradable water-soluble polymers for down-the-drain products such as detergents and cosmetics has taken on increasing importance. Consumers have, however, thus far attached little or no added value to the property of biodegradability, forcing industry to compete head-to-head on a cost-performance basis with existing familiar products.
In addition, no suitable infrastructure for the disposal of biodegradable materials exists as yet. Biodegradable polymers began to provide a solution to the problem of Waste Management relating to Plastics from the 70's. Biodegradable polymer undergoes biodegradation when it is buried in the soil leaving no remains of the polymer or other toxic residues. The biodegradation or mineralization of the polymer is measured by the evolution of carbon dioxide after microbial assimilation.
Over the course of the last many years there have been many patents in the area of biodegradable polymers/plastics.Yet none of these patents has led to products, which have been successful in establishing appreciable application in the overall plastics market due to the difference between biodegradable and degradable. The prior art has failed primarily in one or more of these four areas: 1) the articles lacked sufficient strength, 2) the articles had poor shelf life, 3) the articles were too expensive, and/or 4) processability into a useful article was difficult and expensive. The area where failure occurred most often was in price as some of the roducts manufactured from such biodegradable polymers cost as much as 5-20 times as much as non-biodegradable products available in the market. Another failing of these products is that they are photodegradable thus affecting the tensile strength of the product.
Starch-based polymers and other products merely disintegrate breaking up into minute particles not visible to the naked eye after burial resulting in biomass which may have toxic properties. They are also weak and too brittle by nature and have to be engineered to get the properties of virgin plastic.Another failing of starch-based products is that they lose strength under typical storage conditions through absorption of moisture, which leads to a weakening of the plastic (Sumanam 2009). Cornstarch Cornstarch, material made by pulverizing the ground, dried residue of corn grains after preparatory soaking and the removal of the embryo and the outer covering.
It is used as laundry starch, in sizing paper, in making adhesives, and in cooking. Dextrin, corn syrup, and corn sugar are produced by the hydrolysis of cornstarch.Glycerin Glycerin is produced by various routes from propylene. The epichlorohydrin process is the most important; it involves the chlorination of propylene to give allyl chloride, which is oxidized with hypochlorite to dichlorohydrins, which reacts with a strong base to give epichlorohydrin. Epichlorohydrin is then hydrolyzed to give glycerol. Because of the emphasis on biodiesel, the market for glycerol is depressed, and the old epichlorohydrin process for glycerol synthesis is no longer economical on a large scale.
Only one producer for synthetic glycerol is left, because high-quality glycerol is needed in highly sensitive pharmaceutical, technical and personal care applications. Approximately 950,000 tons per annum are produced in the USA and Europe; 350,000 tons of glycerol were produced per year in the United States alone from 2000-2004. Production will increase as the EU directive 2003/30/EC is implemented, which requires the replacement of 5. 75% of petroleum fuels with biofuel across all Member States by 2010.
It is projected that by the year 2020, production will be six times more than demand.Glycerin was discovered in 1779 by K. W. Scheele and named Olsiiss (principe doux des huiles - sweet principle of oils), and more fully investigated subsequently by M. E.
Chevreul, who named it glycerin, M. P. E. Berthelot, and many other chemists, from whose researches it results that glycerin is a trihydric alcohol indicated by the formula C 3 H 5 (OH) 3j the natural fats and oils, and the glycerides generally, being substances of the nature of compound esters formed from glycerin by the replacement of the hydrogen of the OH groups by the radicals of certain acids, called for that reason "fatty acids. The relationship of these glycerides to glycerin is shown by the series of bodies formed from glycerin by replacement of hydrogen by "stearyl" (C18H350), the radical of stearic acid (C18H350. OH): The process of saponification may be viewed as the gradual progressive transformation of tristearin, or some analogously constituted substance, into distearin, monostearin and glycerin, or as the similar transformation of a substance analogous to distearin or to monostearin into glycerin.
If the reaction is brought about in presence of an alkali, the acid set free becomes transformed into the corresponding alkaline salt; but if the decomposition is effected without the presence of an alkali (i. e. by means of water alone or by an acid), the acid set free and the glycerin are obtained together in a form which usually admits of their ready separation. It is noticeable that with few exceptions the fatty and oily matters occurring in nature are substances analogous to tristearin, i.
e. they are trebly replaced glycerins.Amongst these glycerides may be mentioned the following: Tristearin - C 3 H 5 (O C1 8 H350)3. The chief constituent of hard animal fats, such as beef and mutton tallow, &c.
; also contained in many vegetable fats in smaller quantity. Plastic types Starch based plastics Constituting about 50 percent of the bioplastics market, thermoplasticstarch, such as Plastarch Material, currently represents the most important and widely used bioplastic. Pure starch possesses the characteristic of being able to absorb humidity, and is thus being used for the production of drug capsules in the pharmaceutical sector.Flexibiliser and plasticiser such as sorbitol and glycerine are added so the starch can also be processed thermo-plastically. By varying the amounts of these additives, the characteristic of the material can be tailored to specific needs (also called "thermo-plastical starch"). Simple starch plastic can be made at home shown by this method .
Genetically modified bioplastics Genetic modification (GM) is also a challenge for the bioplastics industry. None of the currently available bioplastics - which can be considered first generation products - require the use of GM crops.Looking further ahead, some of the second generation bioplastics manufacturing technologies under development employ the "plant factory" model, using genetically modified crops or genetically modified bacteria to optimise efficiency. Environmental impact The production and use of bioplastics is generally regarded as a moresustainable activity when compared with plastic production from petroleum (petroplastic), because it relies less on fossil fuel as a carbon source and also introduces fewer, net-new greenhouse emissions if it biodegrades.They significantly reduce hazardous waste caused by oil-derived plastics, which remain solid for hundreds of years, and open a new era in packing technology and industry .
However, manufacturing of bioplastic materials is often still reliant upon petroleum as an energy and materials source. This comes in the form of energy required to power farm machinery and irrigate growing crops, to produce fertilisers and pesticides, to transport crops and crop products to processing plants, to process raw materials, and ultimately to produce the bioplastic, although renewable energy can be used to obtain petroleum independence.Italian bioplastic manufacturer Novamont states in its own environmental audit that producing one kilogram of its starch-based product uses 500g of petroleum and consumes almost 80% of the energy required to produce a traditional polyethylene polymer. Environmental data from Nature Works, the only commercial manufacturer of PLA (polylactic acid) bioplastic, says that making its plastic material delivers a fossil fuel saving of between 25 and 68 per cent compared with polyethylene, in part due to its purchasing ofrenewable energy certificates for its manufacturing plant.A detailed study[ examining the process of manufacturing a number of common packaging items in several traditional plastics and polylactic acidcarried out by US-group and published by the Athena Institute[11] shows the bioplastic to be less environmentally damaging for some products, but more environmentally damaging for others.
While production of most bioplastics results in reduced carbon dioxide emissions compared to traditional alternatives, there are some real concerns that the creation of a global bioeconomy could contribute to an accelerated rate of deforestation if not managed effectively.There are associated concerns over the impact on water supply and soil erosion. Other studies showed that bioplastics represent a 42% reduction in carbon footprint. On the other hand, bioplastic can be made from agricultural byproducts ]and also from used plastic bottles and other containers using microorganisms . Recycling There are also concerns that bioplastics will damage existing recycling projects. Packaging such as HDPE milk bottles and PET water and soft drinks bottles is easily identified and hence setting up a recycling infrastructure has been quite successful in many parts of the world.
However, plastics like PET do not mix with PLA, yielding unusable recycled PET if consumers fail to distinguish the two in their sorting. The problem could be overcome by ensuring distinctive bottle types or by investing in suitable sorting technology. However, the first route is unreliable, and the second costly. Market Because of the fragmentation in the market and still unsettled definitions it is difficult to estimate the total market size for bioplastics, but estimates put global consumption in 2006 at around 85,000 tonnes. In contrast, global consumption of all flexible packaging is estimated at around 12.
million tones.
