Cassava starch as an effective component for Ideal Biodegradable Plastics
An Investigatory Project submitted to
the High School Department of
St. Paul College, Pasig
in partial fulfillment of the
requirements in Chemistry
Submitted by:
Group Number 9
Dianne Marie C. Roxas
Karla Angela P. Sese
Jannica Sibal
Mariel P. Sta. Ana
Teacher: Ms. Mendiola
Date of Submission: December 7, 2009
Abstract
The purpose of this experiment is to be able to help the society with its environmental issues by creating a biodegradable plastic out of Cassava Starch. The researchers will use environment-friendly materials which can be made into biodegradable plastics that will not harm the environment and will not add to pollution problems. Cassava Tubers were ground and squeezed to extract its starch. Starch obtained was weighed and divided into three equal parts; 80 grams in trial 1, trial 2 and trial 3. T1, T2 and T3 also consisted of 60 ml Polyester resin and 50 grams of Polymer MEKP Hardener for T1, 75 grams for T2 and 125 grams in T3. The components in every treatment or trial were mixed, stirred and then poured in 3 different shirts with Petroleum Jelly and then sun-dried. Afterwards, different methods were used to test the effectivity of the plastic. T1, T2 and T3 were sun-dried but they did not look like a plastic at all. The researchers observed the product while waiting for it to dry but there were no signs of turning into a plastic. The Cassava starch was too thick and the researchers realized that it would not turn into a plastic because of its heavy weight and it would take more time before it would dry because of its thickness. After letting T1, T2 and T3 dry under the sun, it became hard. Although the researchers had unexpected results and the Cassava starch did not turn into plastic, studies have already proven that Cassava starch could be used for making various types of packaging products. Cassava is a promising raw material for the development of biodegradable plastics. The research activities have shown and proven that cassava starch is effective in the development of biodegradable packaging materials such as plastics. Studies determined the effectiveness of cassava starch as component of biodegradable plastic. Results confirmed that cassava starch is ideal as tests proved its worth. Therefore, Cassava Starch is an effective component for Biodegradable plastic.
Table of Contents
Introduction…………………………………………………………………………………………………1
Significance of the Study…………………………………………………………………………………...2
Review of Related Literature……………………………………………………………………………….3
Scope and Limitation……………………………………………………………………………………….5
Definition of Terms…………………………………………………………………………………………5
Methodology……………………………………………………………………………………………….7
Data and Results……………………………………………………………………………………………8
Discussion and Analysis…………………………………………………………………………………..12
Conclusion………………………………………………………………………………………………...13
Recommendations…………………………………………………………………………………………13
Bibliography………………………………………………………………………………………………14
Acknowledgment………………………………………………………………………………………….15
I. Introduction
Plastics are used because they are very useful, cheap, manageable and handy. Plastics have been the fastest growing basic material because they are versatile, light weight, energy saving, durable and recyclable. It has become a popular material used in a wide variety of ways. Plastics can last a long time but unfortunately, this same useful quality can make plastic a huge pollution problem. Its long life means it survives in the environment for long periods where it can do great harm. Non-biodegradable plastics are durable but they degrade very slowly; molecular bonds that make plastic so durable make it equally resistant to natural process of degradation. Plastic packaging provides excellent protection for the product, it is cheap to manufacture and seems to last forever. Lasting forever, however, is proving to be a major environmental problem. Plastics are also a huge problem in waste disposal and studies have been made to find a substitute material which can be used in making biodegradable plastics. Because plastic does not decompose, and requires high energy ultra-violet light to break down, the amount of plastic waste in our oceans is steadily increasing. Studies that have been done locally show about 3, 500 particles of plastic per square kilometer of sea off the southern African coast. The world production of plastic is estimated to be more than 100 million tons per year. Plastics are indeed a threat to wild life. A great proof for this is that plastics have been found in the stomachs of sea turtles, birds, and fish all over the world. Tragically, millions of tons of plastic are poisoning our oceans. Plastic pollution harms people, animals, and the environment because it is non-biodegradable. In the marine environment, plastic breaks down into smaller and smaller particles that absorb toxic chemicals, are ingested by wildlife, and enter the food chain that we depend on. People need alternative and effective components of plastic that is safe and biodegradable which will not harm and pollute the earth.
Page 1
II. Problem
Could Cassava Starch be an effective component for ideal Biodegradable plastic?
III. Hypothesis
a. If you’d use the starch of Cassava plant as a component of plastic, then the plastic will be biodegradable.
b. If you’d use the starch of Cassava plant as a component of plastic, then the plastic will be non-biodegradable.
IV. Significance of the Study
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,
Page 2
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.
V. 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.
Page 3
Research has been done onbiodegradableplastics that break down with exposure to sunlight (e.g.,ultra-violet radiation), water or dampness, bacteria, enzymes, wind abrasion and some instances rodent pest or insect attack are also included as forms ofbiodegradationorenvironmental 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.Starchpowder 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 actuallygenetically engineeredbacteria that synthesize a completely biodegradable plastic, but this material, such asBiopol, 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
Page 4
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.
VI. Scope and Limitations
This experiment only covers plastic bags, not including other plastic materials such as plastic containers, plastic cups, straws and other plastic utensils. The experiment can be done in a matter of 2 hours, excluding the sun-drying procedure. Most of the materials used in the experiment are accessible and can be bought in supermarkets. However, there are a few which are not available in nearby stores. Premix Polyester Resin and Polymer MEKP Hardener are manufactured by Polymer Products (Phil) Inc. and can be bought in Bagong Ilog, Pasig City.
VII. 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.
Page 5
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 plants, particularly coniferous trees. It is valued for its chemical constituents and uses, such as varnishes and 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
Page 6
"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. Once the plastic resins have been formed, they are used to make many different kinds of products.