Be report sem viii final


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Be report sem viii final

  2. 2. 2 A PROJECT REPORT ON “BIOPLASTICS- UTILIZATION OF WASTE BANANA PEELS FOR SYNTHESIS OF POLYMERIC FILMS” Submitted to UNIVERSITY OF MUMBAI At Semester VIII of Academic Year 2013-2014 In partial fulfilment of the requirements for the degree of B.E.CHEMICAL ENGINEERING BY Abhijit Mohapatra (60011100028) Shruti Prasad (60011100034) Hemant Sharma (60011100054) SHRI VILE PARLE KELAVANI MANDAL’S D.J.SANGHVI COLLEGE OF ENGINEERING VILE PARLE (W), Mumbai-400056
  3. 3. 3 Shri Vile Parle Kelvani Mandal’s DWARKADAS J. SANGHVI COLLEGE OF ENGINEERING VILE PARLE (WEST), MUMBAI- 400 056 CERTIFICATE This is to certify that the following students whose names are given below have successfully completed the B.E. (Chemical Engineering) project entitled “Bioplastics-Utilization of Waste Banana Peels for Synthesis of Polymeric Films” At Dwarkadas J. Sanghvi college of Engineering, Mumbai as a partial fulfilment of the requirement for the degree of Chemical Engineering (Semester VIII) of University Of Mumbai in the year 2013-2014. Submitted By: - Abhijit Mohapatra 60011100028 Shruti Prasad 60011100034 Hemant Sharma 60011100054 Internal Guide External Examiner HOD Prof. Sanjay Dalvi Chemical Engg Dept Dr V Ramesh
  4. 4. 4 Acknowledgement We would like to take this opportunity to thank the Chemical Engineering Department for their utmost support towards our final year project. We appreciate the immense help and guidance offered by our mentor, Prof. Sanjay Dalvi. We would like to thank our HOD, Dr. V.Ramesh for letting us use the laboratories and the equipments for our project work. We would also like to take this opportunity to express our gratitude to Prof E. Narayanan (Mentor Prof- Production Dept) Prof D. D. Kale (ex ICT Faculty), Mr Tushar Dongre (Sr Manager-Technical, Reliance Industries) for their guidance. We also thank the Applied Chemistry Depart (MPSTME & DJSCOE), Manuben Nanavati College of Pharmacy for being supportive of our work and helping us with our project. Lastly we would like to thank Mrs. Jyotsna, Mr. Jaisingh and Mr. Nitin, for providing us with the necessary help in the laboratories.
  5. 5. 5 Abstract The diminishing supply of petroleum along with the pollution caused due to the non- biodegradability of petroleum based plastics, has led to an increased interest in the field of bioplastics. The initial sections of this report begin with the history of plastics followed by bioplastics. A brief economic study of bioplastic has also been discussed in this report. Applications, advantages and disadvantages are also mentioned to give the reader a broader understanding of the scenario. The latter section of the project endeavours to study a novel method in the production of biopolymers using waste banana peels. Variations in synthesis parameters like pH, plasticizer choice and hydrolysis times were extensively tested and the optimum combination was obtained.
  6. 6. 6 Table of Contents Chapter No Name Page No 1 Literature Survey 7 2 Plastics 9 3 Bioplastics 16 4 Experimental Procedure 38 5 Testing Procedure 44 6 Experimental Trials Conducted 47 7 Observations 53 8 Calculations 56 9 Analysis 61 10 Preliminary Process Scheme 68 11 Future Scope 71 12 References 73
  7. 7. 7 Chapter 1 Literature Survey
  8. 8. 8 Literature survey The Royal Society of Chemistry describes the generic process for the manufacture of starch based bioplastics. This involves hydrolysis of the starch by using an acid. Abdorreza et al (2011) have described in their paper the physiological, thermal and rheological properties of acid hydrolyzed starch. This paper shows that the amylose content increases initially but continuous hydrolysis causes a decrease in the amylose content. This fact is also corroborated in the paper by Karntarat Wuttisela et al (2008). The amylose content is responsible for the plastic formation in starch. Plasticizers are used to impart flexibility and mouldability to the bioplastic samples. Thawien Bourtoom, of the Prince of Songkla University, Thailand, in his paper (2007) discusses the effects of the common types of plasticizers used and their effects on various properties like tensile strength, elongation at break and water vapour permeability of the bioplastic film. Applications of bioplastics, especially in the packaging industry have been discussed in the paper by Nanou Peelman et al (2013) where biobased polymers used as a component in (food) packaging materials is considered, different strategies for improving barrier properties of biobased packaging and permeability values and mechanical properties of multi-layered biobased plastics is also discussed.
  9. 9. 9 Chapter 2 Plastics
  10. 10. 10 2. Plastics 2.1 History A plastic is a type of synthetic or man-made polymer; similar in many ways to natural resins found in trees and other plants. Webster's Dictionary defines plastics as: any of various complex organic compounds produced by polymerization, capable of being moulded, extruded, cast into various shapes and films, or drawn into filaments and then used as textile fibres. The development of artificial plastics or polymers started around 1860, when John Wesley Hyatt developed a cellulose derivative. His product was later patented under the name Celluloid and was quite successful commercially, being used in the manufacture of products ranging from dental plates to men’s collars. Over the next few decades, more and more plastics were introduced, including some modified natural polymers like rayon, made from cellulose products. Shortly after the turn of the century, Leo Hendrik Baekeland, a Belgian-American chemist, developed the first completely synthetic plastic which he sold under the name Bakelite. In 1920, a major breakthrough occurred in the development of plastic materials. A German chemist, Hermann Staudinger, hypothesized that plastics were made up of very large molecules held together by strong chemical bonds. This spurred an increase in research in the field of plastics. Many new plastic products were designed during the 1920s and 1930s, including nylon, methyl methacrylate, also known as Lucite or Plexiglas, and polytetrafluoroethylene, which was marketed as Teflon in 1950. Nylon was first prepared by Wallace H. Carothers of DuPont, but was set aside as having no useful characteristics, because in its initial form, nylon was a sticky material with little structural integrity. Later on, Julian Hill, a chemist at DuPont, observed that, when drawn out, nylon threads were quite strong and had a silky appearance and then realized that they could be useful as a fibre. The World Wars also provided a big boost to plastic development and commercialization. Many countries were struck by a shortage of natural raw materials during World War II. Germany was
  11. 11. 11 cut off quite early on from sources of natural latex and turned to the plastics industry for a replacement. A practical synthetic rubber was developed as a suitable substitute. With Japan’s entry into the war, the United States was no longer able to import natural rubber, silk and many metals from most Far Eastern countries. Instead, the Americans relied on the plastics industry. Nylon was used in many fabrics, polyesters were used in the manufacturing of armour and other war materials and an increase in the production synthetic rubbers occurred. Advances in the plastics industry continued after the end of the war. Plastics were being used in place of metal in such things as machinery and safety helmets, and even in certain high- temperature devices. Karl Ziegler, a German chemist developed polyethylene in 1953, and the following year Giulio Natta, an Italian chemist, developed polypropylene. These are two of today’s most commonly used plastics. During the next decade, the two scientists received the 1963 Nobel Prize in Chemistry for their research of polymers.[1] 2.2 Classification, Structure and Uses Plastics are essentially a by-product of petroleum refining. In plastics production, the components of oil or natural gas are heated in a cracking process, yielding hydrocarbon monomers that are then chemically bonded into polymers. Different combinations of monomers produce polymers with different characteristics. The basic backbone of a hydrocarbon polymer is a chain of carbon atoms, with hydrogen atoms branching off the carbon spine. Some plastics contain other elements as well. For example, Teflon contains fluorine, PVC contains chlorine, and nylon contains nitrogen. Plastics have vast applications in all walks of life. They are used from manufacturing of packaging items, furniture, and fabrics to medical equipment and construction articles. There are various reasons for the popularity of plastics. Some of them are  Low cost  Resistance to chemical solar and microbial degradation  Thermal and chemically insulating properties  Low weight
  12. 12. 12 Plastics can also be custom-designed for innumerable uses like prosthetic limbs, bullet proof vest etc. The use of plastic materials in cars and airplanes reduces their weight and therefore increases their fuel efficiency. Plastics are broadly classified into two main categories. These are explained in the table below which gives a broad overview of both the types. [4] 2.3 Problems associated with plastics Despite their many uses and desirable properties, petroleum based conventional plastics have many disadvantages. The major reasons for looking at alternatives to plastics are because of the following drawbacks: 1. Production Problems Plastics are derivatives of petroleum, natural gas or similar substances. They are transformed into a polymer resin, which is then shaped and formed into whatever object is desired. However, as a petroleum by-product, plastics contribute to oil dependency, and in the present times it is generally recognized that oil will not be available indefinitely. This points to a possible raw Plastics Thermosets 1. Solidifies or sets irreversibly when heated. 2.The molecules of these plastics are cross linked in three dimensions and this is why they cannot be reshaped or recycled. 3.They are useful for their durability and strength. 4. Used primarily in automobiles and construction applications. Other uses are adhesives, inks, and coatings. Thermoplastics 1. Softens when exposed to heat and returns to original condition at room temperature. 2. Do not undergo significant chemical change. 3. Weak bond, which becomes even more weak on reheating. 4. Thermoplastics can easily be shaped and molded into products such as milk jugs, floor coverings, credit cards, and carpet fibers
  13. 13. 13 material crisis in the future. 2. Plastic Recycling Although many types of plastics could potentially be recycled, very little plastic actually enters the recycling production process. The most commonly recycled type of plastic is polyethylene terephthalate (PET), which is used for soft drink bottles. Approximately 15 to 27 percent of PET bottles are recycled annually. The other type of plastic which is somewhat commonly recycled is high-density polyethylene (HDPE), which is used for shampoo bottles, milk jugs and two thirds of what are called rigid plastic containers. Approximately 10 percent of HDPE plastic is recycled annually. These figures show that most of the plastics manufactured do not get recycled and as production continues unabated, this poses a serious problem. 3. Landfill Disposal The vast majority of plastics, especially plastic bags, wind up in landfills. The fact that available landfill space is becoming increasingly scarce and plastics are non biodegradable poses special problems for landfills. Compounding the issue is the survey (Zero Waste America. (1988-2008)) which found that 82 percent of the surveyed landfill cells had leaks, while 41 percent had a leak larger than 1 square foot. Also these leaks are detectable only if they reach landfill monitoring wells. Both old and new landfills are usually located near large bodies of water, making detection of leaks and their cleanup difficult. All these issues point to the fact that landfill disposal of plastics is not a sustainable solution. 4. Incineration Some industry officials have promoted the incineration of plastic as a means of disposal. A similar process of pyrolysis breaks plastics into a hydrocarbon soup which can be reused in oil and chemical refineries. However, both incineration and pyrolysis are more expensive than recycling, more energy intensive and also pose severe air pollution problems. In 2007, the EPA
  14. 14. 14 acknowledged that despite recent tightening of emission standards for waste incineration power plants, the waste-to-energy process still “create significant emissions, including trace amounts of hazardous air pollutants”. Incinerators are a major source of 210 different dioxin compounds, plus mercury, cadmium, nitrous oxide, hydrogen chloride, sulphuric acid, fluorides, and particulate matter small enough to lodge permanently in the lungs. (U.S. Environmental Protection Agency. (2007, December 28). Air Emissions) 5. Adverse effect on Biodiversity Plastic debris affects wildlife, human health, and the environment. Plastic pollution has directly or indirectly caused injuries and deaths in 267 species of animals (including invertebrate groups) that scientists have documented. These problems are because of various reasons which include poisoning due to consumption of plastics, suffocation due to entanglement in plastic nets etc. The millions of tons of plastic bottles, bags, and garbage in the world's oceans are breaking down and leaching toxins posing a threat to marine life and humans. Some marine species, such as sea turtles, have been found to contain large proportions of plastics in their stomach. When this occurs, the animal typically starves, because the plastic blocks the animal's digestive tract. In some cases small bits of plastics are accidently consumed by animals. Any such animal, if eaten by another will cause the plastics to travel up the food chain. This may cause serious health hazards in a wide array of creature. 6. The Carbon Cycle When a plant grows, it takes in carbon dioxide, and when it biodegrades, it releases the carbon dioxide back into the earth – it’s a closed loop cycle. When we extract fossil fuels from the earth, we disrupt the natural cycle, and release carbon dioxide into the atmosphere faster than natural processes can take it away. As a result, the atmosphere is getting overloaded with carbon dioxide. Additionally, fossil fuels take millions of years to form, and are therefore non-renewable resources. In other words, we are using our fossil resources faster than they can be replaced. When we make products like plastics from fossil fuels, we are contributing to the imbalance in the environment while depleting valuable fossil resources, thereby increasing the carbon
  15. 15. 15 footprint of the product. Bioplastics, on the other hand, can replace nearly 100% of the fossil fuel content found in conventional plastics, and require considerably less energy for production. [2], [3] [5] Plastics are so vital to our lives and so versatile in their usage, their use cannot be completely stopped. Hence alternative solutions to this problem are being looked into. The most promising answer seems to be coming in the form of bioplastics.
  16. 16. 16 Chapter 3 Bioplastics
  17. 17. 17 3. Bioplastics 3.1 Introduction Plastics that are made from renewable resources (plants like corn, tapioca, potatoes, sugar and algae) and which are fully or partially bio-based, and/or biodegradable or compostable are called bioplastics. European Bioplastics has mentioned 2 broad categories of bioplastics:  Bio based Plastics: The term bio based means that the material or product is (partly) derived from biomass (plants). Biomass used for bioplastics stems from plants like corn, sugarcane, or cellulose.  Biodegradable Plastics: these are plastics which disintegrate into organic matter and gases like CO2, etc in a particular time and compost which are specified in standard references (ISO 17088, EN 13432 / 14995 or ASTM 6400 or 6868). However, it should be noted that the property of biodegradation does not depend on the resource basis of a material, but is rather linked to its chemical structure. In other words, 100 percent bio based plastics may be non-biodegradable, and 100 percent fossil based plastics can biodegrade. [22]
  18. 18. 18 The figure below explains the broad categories into which bioplastics are divided. [22] Thus all the highlighted regions in the graph represent bioplastics. They can thus be bio based- biodegradable, non bio based-biodegradable and bio based-non biodegradable.
  19. 19. 19 The table below gives a short comparison of various properties of both the plastics. [17]
  20. 20. 20 3.2 History Event Date: Event: 1st Jan, 1862 The First Man-made Plastic (Bioplastic) : At the Great International Exhibition in London, Alexander Parkes (1813- 1890), a chemist and inventor, displayed a mouldable material made of cellulose nitrate and wascalles called Parkesine. Parkesine was greeted with great public interest, so Parkes began the Parkesine Company at Hackney Wick, in London. However it wasn’t very successful commercially. 8th Aug, 1869 Reinvention: After the fall of the Parkesine Company, a new name in bioplastics surfaced. In 1869, John Wesley Hyatt, in an effort to find a new material for billiard balls other than ivory, invented a machine for the production of stable bioplastic. He was able to patent the material as Celluloid. 28th Mar, 1907 Discovery of Conventional Plastics: The discovery of petroleum plastics. The beginning of a long road that is coming to a dead end. 8th Sep, 1924 Ford Goes Bioplastic: In the 1920's, Henry Ford, in an attempt to find other non-food purposes for Agricultural surpluses. Ford began making bioplastics for the manufacturing of automobiles. The bioplastics were used for steering wheels, interior trim and dashboards. Ford has been using them ever since. 12th Jun, 1933 The Discovery of Polyethylene : In 1933, two chemists, E.W. Fawcett and R.O. Gibson discovered polyethylene on accident. While experimenting with ethylene and benzaldehyde, the machine that they were using sprang a leak and all that
  21. 21. 21 Event Date: Event: was left was polyethylene. They were credited with the discovery of the polymerization process. 13th Aug, 1941 The First Bioplastic Car: Henry Ford unveiled the first plastic car in 1941. This car had a bioplastic body and parts consisting of 14 different bioplastics. There was a lot of interest, but soon after, WWII started and attentions were diverted. 9th Aug, 1990 A British Company, Imperial Chemical Industries, developed a bioplastic, Biopol, which is biodegradable. This was the beginning of the bioplastic revolution. [1]
  22. 22. 22 3.3 Life Cycle The figure below shows the lifecycle of a generic bioplastic. [2]
  23. 23. 23 3.4 Economic Scenario Bioplastics are used in an increasing number of markets – from packaging, catering products, consumer electronics, automotive, agriculture/horticulture and toys to textiles and a number of other segments. The world currently utilises approximately 260 million tonnes of plastics each year. Bioplastics make up about 0.1% of the global market. 3.4.1 Market Size Growing demand for more sustainable solutions is reflected in growing production capacities of bioplastics: in 2011 production capacities amounted to approximately 1.2 million tonnes. Market data of “European Bioplastics” forecasts the increase in the production capacities by fivefold by 2016 – to roughly 6 million tonnes. The factors driving market development are both internal and external. External factors make bioplastics the attractive choice. This is reflected in the high rate of consumer acceptance. Moreover, the extensively publicised effects of climate change, price increases of fossil materials, and the increasing dependence on fossil resources also contribute to bioplastics being viewed favourably.
  24. 24. 24 [13], [2] COPA (Committee of Agricultural Organisation in the European Union) and COGEGA (General Committee for the Agricultural Cooperation in the European Union) have made an assessment of the potential of bioplastics in different sectors of the European economy:
  25. 25. 25 Product Tonnes/ year (2001) Catering products 450,000 Organic waste bags 100,000 Biodegradable mulch foils 130,000 Biodegradable diaper foils 80,000 Foil packaging 240,000 Vegetable packaging 400,000 Tyre components 200,000 Total 2,000,000 The market research institute Ceresana expects the global bioplastics market to reach revenues of more than US$2.8 billion in 2018 - reflecting average annual growth rates of 17.8%. Bioplastics are supposed to contribute to protecting the climate, provide a solution for the waste issue, reduce the dependence on fossil raw materials, and improve the image of plastic products. With a roughly 35% share, Europe was the largest outlet for bioplastics in 2010, followed by North America and Asia-Pacific. [13] 34.6% 13.7% 0.4% 32.8% 18.5% Gobal production capacity of bioplastics in 2011 (by region) Asia North America Australia South America Europe Total: 1,161,200 tonnes
  26. 26. 26 Over the next eight years, shares in demand of the individual world regions will shift significantly. Ceresana forecasts two regions to considerably influence the bioplastics market. Because of dynamic growth in consumption and production, Asia-Pacific will expand its share of bioplastics demand. As a result, Asia-Pacific will almost draw level with Europe and North America. In addition, South America will see strong growth, mainly because of massive increases in production in Brazil . [13] 3.4.2 Cost With the exception of cellulose, most bioplastic technology is relatively new and currently not cost competitive with (petro plastics). Bioplastics do not reach the fossil fuel parity on fossil fuel derived energy for their manufacturing, reducing cost advantage over petroleum-based plastic. 0.2% 45.1% 46.3% 4.9% 3.5% Global production capacity of bioplastics in 2016( by region) South America Asia Europe North America Australia Total: 5,778,500 tonnes
  27. 27. 27 [17] Forecast market growth is predicted to be greatest in non-biodegradable bioplastics. Bioplastics could also be used in more sophisticated applications such as medicine delivery systems and chemical microencapsulation. They may also replace petrochemical-based adhesives and polymer coatings. However, the plastics market is complex, highly refined and manufacturers are very selective with regard to the specific functionality and cost of plastic resins. For bioplastics to make market grounds they will need to be more cost competitive and provide functional properties that manufacturers require. 15% 15% 20% 40% 10% Bioplastics Market Share Cellulose acetate Polylactic Acid (PLA) Extruded Starch Thermoplastic Starch/ Blends Polyhydroxyalkanoates (PHAs) and others
  28. 28. 28 3.5 Applications [13] Bioplastics are used in a wide variety of fields. Some of them are: 3.5.1 Packaging Today, biopackaging can be found in many European supermarkets. Sainsbury in the UK may be cited as a pioneer – who first recognised the opportunities for compostable plastics packaging. Many Supermarket chains such as Delhaize (Belgium), Iper (belonging to the Carrefour group; Italy), Albert Heijn (Netherlands) and Migros (Switzerland) are actively placing their trust in biopackaging. Last year, the world`s largest retailer, Wal-Mart, introduced its first range of products in corn-based PLA packaging throughout the USA. For supermarkets, it is also an enormous advantage to be able to compost unsold perished food products cheaply together with their packaging rather than have to separate the contents from the
  29. 29. 29 packaging at considerable cost. Food residues do not interfere in the slightest with this recycling. The same applies to compostable service packs, such as trays, plates, cups or cutlery. i. Bags Concerns over litter, the perceived waste of a single use item and the management of bio-waste have made this one of the fastest growing sectors for bioplastics in the early 21st century. Bioplastics form excellent replacements to conventional oil based materials in this sector with great performance characteristics, strength, good contact clarity and proven high speed production. ii. Wraps Bioplastics can be converted into waterproof and fat resistant film for a wide variety of wrapping and packing eco-options. A great natural feel and appropriate barrier technology allows products like cheese to breathe on the path to the consumer. Flexible materials with paper-like dead-fold characteristics broaden the application range. [7], [9], [10], [16], [20], [23] 3.5.2 Agriculture & Horticulture The usually inherent property of biodegradability offers specific advantages in agriculture and horticulture. i. Mulch film Bioplastics can be converted into fully opaque or semi-transparent films that provide the ideal growing environment yet can be ploughed into the ground at the end of the growth cycle, providing soil nutrition for future seasons. Producing pure foods with a minimum of pesticide use is a powerful sales argument in vegetable-growing or organic farming. Ploughing-in mulching films after use instead of collecting them from the field, cleaning off the soil and returning them for recycling, is practical and improves the economics of the operation.
  30. 30. 30 Mulch Films made of PLA Bioplastics ii. Tree protectors and Plant supports/stakes: Bioplastics are being developed as an answer to forest litter, providing a guard that enables young trees to get the best possible start. Protection from vermin and hostile environment is assured early in the growing cycle but the material will bio-disintegrate as the tree passes into maturity. Unsightly litter is removed and collection costs on managed woodland eliminated. Horticulturalists now choose bioplastics to make functional plant holders that are strong, water resistant, in a choice of colours and have the ability to decompose naturally into biomass. [7], [23], [24] 3.5.3 Personal Care and Hygiene Most personal care items like toothbrushes, razors etc can be manufactured from bioplastics. Matt finishing of the bioplastics ensures that the plastic razor has good grip and gives a smooth shave. The material surface characteristics ensure good grip performance whilst providing a device that will withstand every day use. Testing for products in this sector has demonstrated suitable thermal, moisture and fatigue performance. Meanwhile bioplastics can be blown to form opaque, soft-feel bottles for the likes of shampoos and creams. Complementing bioplastic caps can be injection or compression moulded.
  31. 31. 31 These products are one time use and throw products, if bioplastics can be used here, it can solve the problem of plastic as a gross waste to a large extent.[7],[23] 3.5.4 Electronics In 2009, Japanese multinational, NEC has successfully developed and implemented a flame- retardant bio-plastic that can be used in electronic devices due to its high flame retardancy and processability. The new bioplastic includes more than 75% biomass components, and can be produced using manufacturing and moulding processes that halve the CO2 emissions of conventional processes used to make petroleum-based flame-retardant plastics (PC/ABS plastics). NEC's new bioplastic is therefore one of the most environmentally friendly flame retardant plastics used for casing of electronic devices in the world In another case, Mitsubishi Plastics, Inc has already succeeded in raising the heat-resistance and strength of polylactic acid by combining it with other biodegradable plastics and filler, and the result was used to make the plastic casing of a new version of Sony Corp.'s Walkman. Mitsubishi Plastics had previously looked at bioplastic as something that would mainly be used in the manufacture of casings and wrappings, but the company now feels confident that this revolutionary material has entered a new phase in its development in which more complex applications will be found. [14] 3.5.5 Automobiles Ford Motor Corp. was the first automaker in the world to use bioplastics in the manufacture of auto parts way back in the 1920s. Recently, Toyota motor corp. employed them in the cover for
  32. 32. 32 the spare tire in the Raum, a new model that went on sale this May. The bioplastic used here is polylactic acid (PLA) is made from plants, such as sweet potatoes and sugarcane. A spokesperson for Toyota Motor's Biotechnology and Afforestation Business Division expresses high hopes for the future of bioplastics, saying, "The inside of a car gets very hot and is exposed to shocks while the vehicle is running. If bioplastics can be used in this tough environment, they can be used in ordinary household products or anywhere else."[15] 3.5.6 Food Packing In a new study published on June 6, 2013 in the peer-reviewed scientific journal Trends in Food Science and Technology, researchers from the University of Gent review the application of bioplastics in food packaging (Peelman et al 2013). The main bioplastics are polylactide (PLA), starch, polyhydroxyalkanoates (PHA) and cellulose. PLA is the most widely used bioplastics with application for fresh foods, dry foods such as pasta and potato chips, fruit drinks, yoghurt, and meat. Starch has been used as an alternative for polystyrene (PS) to package tomatoes and chocolate. Cellulose is used to package dry foods and fresh produce. While all of these materials are biodegradable, their functional limitations have so far restricted their widespread application in food packaging. As outlined by Peelman and colleagues, the main limitations of the four materials is their brittleness, thermal instability, low melt strength, difficult heat sealability, high vapour and oxygen permeability, poor mechanical properties, stiffness and poor impact resistance. In their study Peelman and colleagues review three processes, which may be used to improve the properties of bioplastics, namely coating, blends and chemical/physical modifications. i. Coating Coating comprises the application of a thin bio based or non-bio based layer to the bioplastics. Such coatings can lower the oxygen and vapour permeability, increase tensile strength and result in higher elastic properties. ii. Blending Blending bioplastics is another approach to improve functionality. Cellulose and other bio based materials may be used to create improved blends. Most bioplastics are immiscible; however the
  33. 33. 33 introduction of functional groups, chemical modification or esterification can enhance compatibility. Blending can reduce brittleness, increasing vapour water barrier properties, flexibility, and tensile strength. iii. Chemical and/or physical modification The third approach to improve functionality is chemical and/or physical modification. It can be used to enhance compatibility between two polymers or to improve the functional properties directly. Citric acid added to starch films improves water and vapour properties (WVP). Crosslinking cellulose acetate with phosphates improves tensile strength and slows water uptake and degradation. Epichlorohydrin-modified starch has an increased tensile strength and improved elongation. Partially substituting wheat gluten with hydrolyzed keratin or soaking wheat gluten film in CaCl2 and distilled water improves the water vapour and oxygen barrier properties of a wheat gluten derived film. Peelman and colleagues conclude that using coatings, blending and chemical/physical modification can extend the use of bioplastics in food packaging to a wide variety of food other than fresh produce and dry foods. [16] 3.5.7 Construction The Institute of Building Structures and Structural Design (ITKE) at the University of Stuttgart (Germany) has worked on fibre-reinforced polymers, bionics and the development of new building materials. Architect Carmen Köhler is investigating the applicability of natural fibre- reinforced biopolymers in the construction industry. In contrast to fibreglass-reinforced polymers, natural fibre-reinforced polymers are considerably lighter, emission stable and breathable. “Construction material that is breathable at the same time as preventing moisture from penetrating, is also of major interest in architectural terms,” said Carmen Köhler explaining that she finds the material suitable for facades and insulations. The group of researchers are currently investigating polylactide, cellulose acetate and other materials. Selection criteria are price, temperature stability and the potential use of additives during processing. “We hope that the material will be classified as B2 or even B1 class construction material,” said Köhler explaining that B1 and B2 refer to the degree of imflammability of materials, which should be as low as possible.
  34. 34. 34 Classification: A1 (100% non-combustible) A2 (~98% non-combustible) B1 difficult to ignite B2 normal combustibility (like wood) B3 easily ignited The testing of the material has shown that cellulose acetate and polylactide (PLA) are very resistant to UV. The biopolymers did not become discoloured to the same extent as traditional transparent polymers when exposed to sunlight. Cellulose acetate is already used for transparent heat insulation. But there are a lot more markets starting to use bioplastic materials such as buildings and construction, household, leisure or fibre applications (clothing, upholstery). Products that show vast growth rates include bags, catering products, mulching films or food/beverage packaging. Functional properties are often crucial in the user decision. The environmental aspect and the very high consumer acceptance are additional selling points. [8]
  35. 35. 35 3.6 Advantages of Bioplastics 3.6.1 Eco Friendly Traditional plastics are the petroleum based plastics which depend on fossil fuels which is an unsustainable source. Also acquiring fossil fuels does a lot of harm to the natural environment. Bioplastics on the other hand are made from bio mass like trees, vegetables, even waste which is completely bio degradable. So bioplastics are made from completely renewable source. Even during the manufacturing of plastics, a lot of pollution occurs, for example, during production, PVC plants can release dioxins, known carcinogens that bio-accumulate in humans and wildlife and are associated with reproductive and immune system disorders 3.6.2 Require less time to degrade Traditional plastics take thousands of years to degrade, these plastics lie in the environment, most notably on the ocean floor where they do the maximum damage for years. These plastics hamper the growth and kill the natural habitats. Bioplastics on the other hand, require considerably less time to biodegrade. This degradation can be carried out at home for some bioplastics and even for the bioplastics which require specific conditions, time required to degrade completely is considerably less. This reduces the huge pressure on our existing landfills 3.6.3 Toxicity Some of the plastics degrade rapidly in the oceans releasing very harmful chemicals into the sea, thus harming the animals, plants and also harming the humans by entering the food chain. Biodegradable plastics are completely safe and do not have any chemicals or toxins. This plastic harmlessly breaks down and gets absorbed into the earth. Such advantages of bioplastics are of extreme importance, as the toxic plastic load on the earth is growing and at this rate will cause a whole range of problems for future generations 3.6.4 Lower energy consumption Companies still use fossil fuels for the manufacture of bioplastics; however, many bioplastics use considerably less fuel for their manufacture. For example,
  36. 36. 36 Polylactic acid production requires less energy than other plastics 3.6.5 Environmental protection Burning fossil resources increases the share of CO2 in atmosphere, which causes an increase of the average temperature (greenhouse effect). Scientists see a distinct connection between CO2 increase in atmosphere and the increase of number of thunderstorms, floods and aridity. Climate protection is nowadays a central part of environmental policy, due to the fact that climate change can create far-reaching negative consequences. Governments and organisations work against this threat with targeted measures. [3], [8], [11], [18]
  37. 37. 37 3.7 Challenges for Bioplastics 3.7.1 Misconceptions Even though bio degradable plastics are considered to be good for the environment, they can harm the nature in certain ways. Emission of Greenhouse gases like methane and carbon dioxide, while they are degrading, is very large at landfill sites. This can be handled by designing plastics so that they degrade slowly or by collecting the methane released and use it elsewhere as fuel. Some bioplastics need specific conditions to bio degrade, these conditions may not be available at all the landfills or consumers may not have access to landfills, in such case it becomes important to design bioplastics which are bio degradable in a normal soil compost 3.7.2 Environmental Impact Starch based bioplastics are produced generally from plants like corn, potatoes and so on. This puts massive pressure on the agricultural crops as they have to cater the need of ever growing population. To make plastics, crops have to be grown and this could lead to deforestation Bioplastics are generally produced from crops like corn, potatoes, and soybeans. These crops are often genetically modified to improve their resistance to diseases, pests, insects etc. and increase their yield. This practise however carries a very high risk to the environment as such crops can be toxic for humans as well as for animals. [17] 3.7.3 Cost Bioplastics are a newer technology and require still more research and development to get established. Bioplastics are not thus, comparable to plastics with respect to cost.
  38. 38. 38 Chapter 4 Experimental Procedure
  39. 39. 39 4.1 Experimental Procedure 4.1.1 Preparation of Banana Skins Step 1: Banana peels are boiled in water for about 30 minutes Step 2: The water is decanted from the beaker and the peels are now left to dry on filter paper for about 30 minutes Step 3: After the peels are dried, they are placed in a beaker and using a hand blender, the peels are pureed until a uniform paste is formed. 4.1.2 Production of Polymer Step 1: 25gm of banana paste is placed in a beaker Step 2: 3ml of (0.5 N) HCl is added to this mixture and stirred using glass rod. Step 3: 2ml Plasticizer is added and stirred. Step 4: 0.5 N NaOH is added according to pH desired, after a desired residence time. Step 5: The mixture is spread on a ceramic tile and this is put in the oven at 120o C and is baked till dry. Step 6: The tile is allowed to cool and the film is scraped off the surface 4.1.3 Synthesis of plastics was carried out in two phases Stage 1: In this stage, the process parameters pH and Hydrolysis time were changed over a range of values. Each sample produced was then tested for the strength based on the testing procedure mentioned in the following stage. The best combination was obtained and used for the 2nd stage of testing Stage 2: In this stage, the commonly available plasticizers are compared. Based on the values of parameters finalized from the earlier stage, fresh samples were synthesized and tested.
  40. 40. 40 4.2 Reaction Mechanism 4.2.1 Hydrolysis Starch consists of two different types of polymer chains, called amylose and amylopectin, made up of adjoined glucose molecules. The hydrochloric acid is used in the hydrolysis of amylopectin, which is needed in order to aid the process of film formation due to the H-bonding amongst the chains of glucose in starch, since amylopectin restricts the film formation. The sodium hydroxide in the experiment is simply used to neutralize the pH of the medium. Amylopectin Amylose Acid hydrolysis changes the physiochemical properties of starch without changing its granule structure. A research by Kerr et al (1952) said that at the temperature below the gelatinization temperature, the amylopectin region of starch gets hydrolysed preferentially than the amylose region. Also, if the amylopectin content is higher in the starch, the recovery of starch decreases i.e. more of the starch gets hydrolysed. In a research by M.N. Abdorezza et al (2012), native starch obtained from the stem of palm trees was hydrolysed using 0.14N HCl. During the initial stages of hydrolysis, the amylose content increased, this can be attributed to the fact that due the hydrolysis of branched chains of
  41. 41. 41 amylopectin, linear chained amylose were formed. However, if the hydrolysis time was increased up to 6 hours, the amylose content decreased albeit slightly. If this hydrolysis time was increased up to 12 hours, the analysis revealed significant drop in the amylopectin and amylose content of starch. 4.2.2 Addition of NaOH In a study conducted by Ya-Jane Wang et al (2003) Common corn starch was treated with different concentrations of hydrochloric acid, 0.06, 0.14, and 1.0N. It was observed that as the concentration of the acid increased, the rate and the extent of the hydrolysis increased significantly. The 1.0N acid hydrolysed amylopectin as well as amylose to a very large extent. A study was conducted by Karntarat Wuttisella et al (2008) on Analysis of shift of wavelength maximum using rapid colorimetric method was used to determine the Amylose: Amylopectin ratio in native tapioca starch before and after hydrolysis using HCl. The Am:Ap ratio in native tapioca starch was approximately 22:78. The figure below shows that the Am:Ap ratio obtained by an iodometry method at a single wavelength (λ610) measurement decreased with hydrolysis time using 2 M HC1. but not with 0.7 M HC1. This change was seen after 30 min of incubation.[27],[28]
  42. 42. 42 4.2.3 Glycerine as a Plasticizer Plasticizers are generally small molecules such as polyols like sorbitol, glycerol and polyethylene glycol (PEG) that intersperse and intercalate among and between polymer chains, disrupting hydrogen bonding and spreading the chains apart, which not only increases flexibility, but also water vapour and gas permeabilities. Thermoplastic starch (TPS) materials are obtained from granular starch mixed with plasticizers to enable melting below the decomposition temperature. According to a study conducted by A.L.M. Smits, P.H. Kruiskamp, J.J.G. van Soest, J.F.G. Vliegenthart, on heating starch freshly mixed with plasticizers, a strong exothermal interaction enthalpy of ∆H ~ –35 J/g was detected by Differential Scanning Colorimeter (DSC). The transition enthalpy is proportional to the amounts of glycerol or ethylene glycol added, suggesting that the plasticizer is responsible for the observed exothermic event
  43. 43. 43 However, specific interactions between plasticizer and starch chains are difficult to elucidate. It is generally accepted that plasticizers lower the number of physical cross- links between starch chains, and consequently retard the rate of retrogradation. The process is irreversible, since reheating of the samples showed no exothermal enthalpy peak. Heat treatment gives rise to a strong starch-plasticizer interaction, most probably caused by H- bond formation. Plasticizers can be used to influence this ageing induced by retrogradation. For instance, in bread the degree of retrogradation is strongly reduced by the addition of monoglycerides, which interact with the initially amorphous amylopectin. Van Soest et al. showed that an increasing glycerol concentration in a waxy maize starch gel reduces the rate of retrogradation. The inhibiting effect of various saccharides on retrogradation has also repeatedly been reported. A study by the Department of Material Product Technology, Prince of Songkla University, Thailand shows the effect of various commonly used plasticizers viz. sorbitol, glycerol and polyethylene glycol which are studied over a range of concentration from 20 to 60%. The results of this study demonstrates that sorbitol plasticized films provided the films with highest mechanical resistance, but the poorest film flexibility. In contrast, glycerol and polyethylene glycol plasticized films exhibited flexible structure; however, the mechanical resistance was low, while inversely affecting the water vapour permeability. Type and concentration of plasticizers affected the film solubility. Increasing the plasticizer concentration resulted in higher solubility. The colour of biodegradable blend film from rice starch-chitosan was more affected by the concentration of the plasticizer used than by its type.
  44. 44. 44 Chapter 5 Testing Procedure
  45. 45. 45 5. Testing Procedure The following procedure was adopted to test the tensile strength of the samples. The process has the following steps: Step 1. Visual Analysis of the sample to locate any defects in it. If the sample has no defects it can be used for testing. The common forms of defects are i) Perforations and tears in the sample. ii) Very low thickness Step 2. After the sample is approved for testing, a 2cm by 4cm rectangular slice is cut out of the sample for testing. The slice dimensions are kept constant for all samples to ensure uniformity in the testing procedure. Step 3. The slice of sample obtained is the clamped between 2 clips. One end of the clip is attached to a support and the other end has a suspended pan for placing weights in them. Step 4. The clamping positions are also kept constant. The figure below shows the sample with the clamping locations. Applying the thumb rule for tensile strength testing, the samples are clamped such that 60% of the sample is between the clamps and is our testing region. 4cm Sample 20%60%20% 2 cm Step 5. Once the sample has been clamped, weights are added in steps of 10 grams each. A gap of 20 seconds is provided between the addition of weights to allow the sample to stretch and tear.
  46. 46. 46 Step 6. The final weight at which the sample tears is noted using an electronic balance. Step 7. For tensile strength calculations, we use the following formula: The weight is calculated from the electronic balance readings. Now for the cross-sectional area we use a Vernier calliper (TOYO™ Instruments; Least Count = 0.02 mm) to measure the thickness. 5 readings are taken across the length of the sample to consider local variations in thickness and the average of all is computed. The product of the sample width (2 cm) and the average thickness gives us the cross-sectional area of the sample. Thus using the above equation we calculate the tensile strength for all samples. Schematic Representation of testing Apparatus
  47. 47. 47 Chapter 6 Experimental Trials Conducted
  48. 48. 48 6.1 Number of Trials: 6.1.1 Trial 1 conducted on 18/03/2014 Sample pH Residence Time (minutes) Weight of the final paste (grams) Weight of the film (grams) 18/03-1 Acidic 5 33.56 4.095 18/03-2 Acidic 10 32.45 3.72 18/03-3 Acidic 15 31.89 4.361 18/03-4 Acidic 20 32.51 4.133 Status of trial: Rejected Reason: This trial was rejected due to the presence of perforations in the samples which made them unsuitable for testing. 6.1.2 Trial 2 conducted on 19/03/2014 Sample pH Residence Time (minutes) Weight of the final paste(grams) Weight of the film(grams) 19/03-1 Neutral 5 45.205 3.598 19/03-2 Neutral 10 49.668 3.689 19/03-3 Neutral 15 45.365 3.128 19/03-4 Neutral 20 44.663 2.815 Status of trial: Rejected
  49. 49. 49 Reason: This trial was rejected due to the presence of excess water in the paste which made the samples very thin. 6.1.3 Trial 3 conducted on 25/03/2014 Sample pH Residence Time (minutes) Weight of the final paste(grams) Weight of the film(grams) 25/03-4 Basic 5 42.56 5.678 25/03-3 Basic 10 38.286 5.32 25/03-2 Basic 15 43.78 4.88 25/03-1 Basic 20 38.086 4.913 Status of trial: Rejected Reason: This trial was rejected due to the incorrect concentration of NaOH taken for the experiments. This made the sample set inconsistent with any standards of testing. 6.1.4 Trial 4 conducted on 26/03/2014 Sample pH Residence Time (minutes) Weight of the final paste(grams) Weight of the film(grams) 26/03-4 Basic 5 33.849 5.833 26/03-3 Basic 10 34.475 3.852 26/03-2 Basic 15 33.968 4.528 26/03-1 Basic 20 33.946 4.569 Status of trial: All except sample 26/03-3 were accepted and tested.
  50. 50. 50 Reason: This sample 26/03-3 was badly damaged during the production and could not be used for further testing. 6.1.5 Trial 5 conducted on 1/04/2014 Sample pH Residence Time (minutes) Weight of the final paste(grams) Weight of the film(grams) 1/04-4 Neutral 5 33.43 4.344 1/04-3 Neutral 10 33.066 4.409 1/04-2 Neutral 15 32.225 3.823 1/04-1 Neutral 20 32.881 4.197 Status of trial: All except sample 1/04-4 were accepted and tested. Reason: This sample was rejected as it was not evenly baked. 6.1.6 Trial 6 conducted on 1/04/2014 Sample pH Residence Time (minutes) Weight of the final paste(grams) Weight of the film(grams) 1/04-8 Acidic 5 31.649 4.21 1/04-7 Acidic 10 31.365 3.711 1/04-6 Acidic 15 30.018 4.904 1/04-5 Acidic 20 29.997 3.853 Status of trial: All except sample 1/04-6 were accepted and tested. Reason: This sample was rejected as it was not evenly baked.
  51. 51. 51 6.1.7 Trial 7 conducted on 2/04/2014 Sample pH Residence Time (minutes) Weight of the final paste(grams) Weight of the film(grams) 2/04-3 Neutral 5 33.066 4.352 2/04-2 Basic 10 33.605 3.925 2/04-4 Acidic 15 30.661 3.806 Additional Notes: sample 2/04-2 was 26/03-3 performed again Sample 2/04-3- was 1/04-4 performed again Sample 2/04-4 was 1/04-6 performed again Status of trial: Rejected Reason: All were rejected as the baking was incomplete. 6.1.8 Trial 8 conducted on 3/04/2014 Sample pH Residence Time (minutes) Weight of the final paste(grams) Weight of the film(grams) 3/04-3 Neutral 5 33.73 4.61 3/04-4 Basic 10 34.268 4.78 3/04-2 Acidic 15 31.42 3.92 Additional Notes: sample 3/04-4 was 26/03-3 performed again Sample 3/04-3- was 1/04-4 performed again Sample 3/04-2 was 1/04-6 performed again Status of trial: Accepted for testing.
  52. 52. 52 6.1.9 Final Trial conducted on 16/04/2014 using the parameters decided from the initial 8 trials and the results of testing Parameters fixed: pH- Neutral Residence Time-15 minutes Baking temperature- 120o C Sample Plasticizer Weight of the paste (grams) Weight of the film grams) 16/04-2 Glycerine 33.527 3.776 16/04-3 Sorbitol 33.558 3.46 16/04-4 PEG 32.511 3.866
  53. 53. 53 Chapter 7 Observations
  54. 54. 54 7.1 Stage 1: Initial Trial 7.1.1 Weights supported by the samples pH Residence Time (Minutes) Sample Weight (grams) Acidic 5 1/04-8 341.41 10 1/04-7 351.89 15 3/04-2 200.94 20 1/04-5 271.53 Basic 5 26/03-4 331.2 10 3/04-4 160.9 15 26/03-2 240.89 20 26/03-1 131.15 Neutral 5 3/04-3 231.59 10 1/04-3 331.50 15 1/04-2 406.19 20 1/04-1 301.69 7.1.2 Thickness of the samples: pH Sample Thickness (mm) 1 2 3 4 5 Mean Acidic 1/04-8 0.94 0.9 0.8 0.8 0.74 0.836 1/04-7 0.66 0.62 0.6 0.64 0.62 0.628 3/04-2 0.72 0.6 0.48 0.48 0.5 0.556
  55. 55. 55 1/04-5 0.5 0.52 0.54 0.56 0.42 0.508 Basic 26/03-4 0.62 0.6 0.68 0.7 0.62 0.644 3/04-4 0.9 0.84 0.7 0.78 0.94 0.832 26/03-2 0.66 0.66 0.7 0.7 0.84 0.712 26/03-1 0.6 0.52 0.54 0.48 0.58 0.544 Neutral 3/04-3 0.6 0.64 0.74 0.68 0.78 0.688 1/04-3 0.62 0.58 0.66 0.68 0.66 0.64 1/04-2 0.6 0.52 0.54 0.66 0.58 0.58 1/04-1 0.6 0.52 0.54 0.62 0.52 0.56 7.2 Stage 2: Final Trial 7.2.1 Weights supported by the samples pH Plasticizer Residence Time (Minutes) Sample Weight (grams) Neutral Glycerine 15 16/04-2 456.2 Neutral Sorbitol 15 16/04-3 794.95 Neutral PEG 15 16/04-4 558.11 7.2.2 Thickness of the samples: Plasticizer Sample Thickness (mm) 1 2 3 4 5 Mean Glycerine 16/04-2 0.68 0.6 0.6 0.8 0.72 0.68 Sorbitol 16/04-3 0.48 0.5 0.5 0.5 0.6 0.516 PEG 16/04-4 1.1 0.94 0.82 0.8 0.7 0.872
  56. 56. 56 Chapter 8 Calculations
  57. 57. 57 8.1 Stage 1: Initial Trial 8.1.1 Conversion of Weights into forces SR.NO pH Sample Weight (grams) Force(N) 1 Acidic 1/04-8 341.41 3.349232 2 Acidic 1/04-7 351.89 3.452041 3 Acidic 3/04-2 200.94 1.971221 4 Acidic 1/04-5 271.53 2.663709 5 Basic 26/03-4 331.2 3.249072 6 Basic 3/04-4 160.9 1.578429 7 Basic 26/03-2 240.89 2.363131 8 Basic 26/03-1 131.15 1.286581 9 Neutral 3/04-3 231.59 2.271898 10 Neutral 1/04-3 331.50 3.252015 11 Neutral 1/04-2 406.19 3.984724 12 Neutral 1/04-1 301.69 2.959579
  58. 58. 58 8.1.2 Calculation of tensile strengths pH Sample Force (N) Mean thickness of the sample (mm) Area (mm2 ) Tensile Strength (MPa) Acidic 1/04-8 3.349232 0.836 16.72 0.200313 Acidic 1/04-7 3.452041 0.628 12.56 0.274844 Acidic 3/04-2 1.971221 0.556 13.76 0.177268 Acidic 1/04-5 2.663709 0.508 10.16 0.262176 Basic 26/03-4 3.249072 0.644 12.88 0.252257 Basic 3/04-4 1.578429 0.832 16.64 0.094858 Basic 26/03-2 2.363131 0.712 14.24 0.165601 Basic 26/03-1 1.286581 0.544 10.88 0.118252 Neutral 3/04-3 2.271898 0.688 13.76 0.164750 Neutral 1/04-3 3.252015 0.64 12.88 0.254064 Neutral 1/04-2 3.984724 0.58 14.24 0.343511 Neutral 1/04-1 2.959579 0.56 10.88 0.264248
  59. 59. 59 8.1.3 Calculation of conversion: Sample Weight of the final paste(grams) Weight of the film (grams) Conversion % 1/04-8 31.649 4.21 13.3021 1/04-7 31.365 3.711 11.83165 3/04-2 31.42 3.92 12.4761 1/04-5 29.997 3.853 12.8446 26/03-4 33.849 5.833 17.2324 3/04-4 34.268 4.78 13.9488 26/03-2 33.968 4.528 13.3302 26/03-1 33.946 4.569 13.4596 3/04-3 33.73 4.61 13.6673 1/04-3 33.066 4.409 13.3339 1/04-2 32.225 3.823 11.8634 1/04-1 32.881 4.197 12.7642 8.2 Stage 2: Final Trial Performing the final trial with different set of plasticizers, keeping the parameters pH, residence time and baking temperature constant. pH- neutral Residence time- 15 minutes
  60. 60. 60 8.2.1 Calculation of Tensile Strength: Sample Plasticizer Mean thickness of the sample (mm) Area (mm2 )= mean thickness*20 Weight (grams) Force (N)= weight*10-3 * 9.81 16/04-2 Glycerine 0.68 13.6 456.2 0.329068 16/04-3 Sorbitol 0.516 10.32 794.95 0.753474 16/04-4 PEG 0.872 17.44 558.11 0.313937 8.2.2 Calculation of Conversion: Plasticizer Weight of the final paste (grams) Weight of the film (grams) Conversion % Glycerine 33.527 3.776 11.2625 Sorbitol 33.558 3.649 10.8737 PEG 32.511 3.866 11.8913
  61. 61. 61 Chapter 9 Analysis
  62. 62. 62 9.1 Stage 1: Varying pH and Hydrolysis Time 9.1.1 Analysis of neutral sample The tensile strength for neutral sample keeps increasing when the residence times are increased from 5 minutes to 15 minutes and reaches a maximum of 0.3435N/mm2 at 15 minutes and then starts decreasing when the time is increased to 20 minutes. This suggests that the optimum hydrolysis time is 15 minutes for this sample set. According to the research paper “Physicochemical, thermal, and rheological properties of acid-hydrolyzed sago starch” by M.N. Abdorezza et al (2012) native starch obtained was hydrolysed using dilute HCl. During the initial stages of hydrolysis, the amylose content increased, this was attributed to the fact that due the hydrolysis of branched chains of amylopectin, linear chained amylose were formed. However, if the hydrolysis time was increased further, the amylose content decreased albeit slightly. If this hydrolysis time was continued uninterrupted for long durations, the analysis revealed significant drop in the amylopectin and amylose content of starch. This was because once the amylopectin is hydrolysed to amylase, further hydrolysis leads to formation of glucose monomers which do not aid in polymer formation 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0 5 10 15 20 25 TensileStrength(N/mm^2) Residence time (mins) Tensile Strength Vs Residence Time Neutral
  63. 63. 63 9.1.2 Analysis of basic sample The tensile strength for the basic samples keeps decreasing as the residence times are increased from 5 minutes to 20 minutes. Based on the paper “The effect of sodium hydroxide treatment and fibre length on the tensile property of coir fibre” by Karthikeyan et al (2013), the experimental results showed that increasing the amount of NaOH leads to a decrease in fibre diameter in a linear fashion. This reduction in diameter naturally ends up with reduced tensile strength. 0 0.05 0.1 0.15 0.2 0.25 0.3 0 5 10 15 20 25 TensileStrength(N/mm^2) Residence time (mins) Tensile strength Vs Residence Time Basic
  64. 64. 64 9.1.3 Analysis of acidic sample Based on the paper by Abdorezza et al (2007), an increase in residence time for acidic samples should lead to a lesser tensile strength because of excessive hydrolysis. However the graph above shows that the values of tensile strength are fluctuating within a range. This result is a deviation from expected values and needs further research. 9.1.4 Analysis of all the samples (Tensile Strength) 0 0.05 0.1 0.15 0.2 0.25 0.3 0 5 10 15 20 25 TensileStrength(N/mm^2) Residence time (mins) Tensile Strength Vs Residence Time Acidic 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0 5 10 15 20 25 Tensile Strength Vs Residence Time (Combined Plot) Acidic Neutral Basic
  65. 65. 65 9.1.5 Analysis of all samples (Conversion) The conversion being considered in the graph above is not the chemical conversion of the process but a relation of the net mass of polymer obtained per unit mass of the reaction mixture fed into the oven. We can see that these conversions are almost constant for all the samples and are independent of the pH and the residence times. From this it can be inferred that the conversion is predominantly a result of the water losses which take place from the samples. The changes in the chemical compositions, if any, do not contribute to a significant extent From the combined plot, we observe that the maximum tensile strength from all the samples is obtained for the neutral sample which has a residence time of 15 minutes. The average strength of the basic samples, is always lower than the neutral samples. Since the conversion plot does not show much of a variation for any of the sample, the final fixing of the parameters solely depends on the combined plot of tensile strength. Thus from both the combined plots of tensile strength and conversion, we fix  pH – Neutral  Residence time- 15 minute 0 5 10 15 20 25 30 35 40 45 50 0 5 10 15 20 25 %Conversion Residence Time Conversion Vs Residence Time (Combined) Acidic Basic Neutral
  66. 66. 66 as constant parameters for our stage 2 trial, where we conduct the same experiment using different plasticizer. 9.2 Stage 2- Varying the Plasticizer 9.2.1 Analysis of tensile strengths of all samples for different plasticizers 9.2.2 Analysis of conversion of all the samples 0 0.2 0.4 0.6 0.8 Glycerine Sorbitol PEG 400 Tensile Strength for Different Plasticizers Tensile Strength for Different Plasticisers Tensile Strength (N/mm^2) 0 10 20 30 40 50 Glycerine Sorbitol PEG Conversion For Different Plasticizers Conversion %
  67. 67. 67 We can see from the graph that sorbitol exhibits maximum tensile strength followed by Glycerine and PEG 400. This is also the observed data from the paper on“Plasticizer effect on the properties of biodegradable blend film from rice starch-chitosan” by Bourtoom. (2007) from Prince of Songkla University, Thailand. The table below shows the increasing concentration of these plasticizers results in decreased tensile strength (TS) Properties Sorbitol Glycerine PEG Brittleness Least Flexible Flexible structure Flexible structure Tensile strength Highest TS :26.06MPa 14.31MPa 16.14MPa
  68. 68. 68 Chapter 10 Preliminary Process Scheme
  69. 69. 69 Preliminary Process Scheme
  70. 70. 70 Description: Since this form of bioplastic product does not have a fixed, defined market, the production has to be done in a batch process. The location of the plant should be next to a banana processing facility which makes any value added product like banana chips, flour, puree etc. The large amount of banana peel waste generated can be used to make bioplastics in situ. The process for manufacturing the banana based bioplastic is as shown in the flowchart. The banana peels are gathered in a temporary storage vessel for processing. The peels are then moved via a screw conveyor to the washing section where the samples are sprayed with water mixed with mild surfactant to remove the dirt and grit. The samples are then rinsed again to remove the residual surfactants. The peels are then transferred to an agitated vessel with a jacket for heating where the banana peels are boiled. Peels are then filtered to remove excess water and are transferred to stacks of trays to dry on for half an hour. The drying is done at ambient temperature at atmospheric conditions. The dried, boiled peels are then sent to an industrial grinder where they are ground to a paste. This paste is then sent to a reaction chamber. In it the paste is mixed with dilute 0.5N HCl and a suitable plasticizer (here sorbitol) for a residence time of 15 minutes. The reaction taking place here involves acidic hydrolysis of starch. The addition of the plasticizer aids in plastic formation. A tank with paddle type agitator is selected. Paddle agitator will scrape from the sides and not allow for formation of pockets. The reaction mixture is transferred into the neutralization tank to stop the reaction. Here calculated amounts of 0.5N NaOH are added to the reaction mixture to neutralize the acid and stop the reaction. Finally the paste is spread into a thin film and baked in an oven at about 120 deg C. The thin film is peeled off the base and is now ready to use.
  71. 71. 71 Chapter 11 Future Scope
  72. 72. 72 Further Research can be carried out for better understanding of the Process and thereby improving the Quality of the Product. Other commonly available starch sources can be explored. Food wastes like mango seeds and corn kernels also have high starch content. Hence these can also be utilized as a raw material for synthesis of polymeric films. So far we have conducted the experiment using only one set of concentrations (0.5 N NaOH & 0.5N HCl). Varying the concentration of the reagents might alter the properties of the polymeric films obtained. This project focussed primarily on tensile strength measurement. Other standard tests like Izod Impact Test, Dart Impact Test etc. should also be conducted. Synthesis of polymeric films can also be carried out after extraction of starch from banana peels instead of processing it as a whole to see if it improves the polymeric properties. The banana peels consists of many different components apart from starch. Currently only the reaction with starch has been considered. The interaction of all the other components with the reagents may also have an effect which must also be quantified.
  73. 73. 73 Chapter 12 References
  74. 74. 74 Chapter 2 1. tml- Joanne & Stefanie's Plastics Website- “History Of Plastics” 2. Fca0TU - David Guion- “Plastic and environmental problems” 3. Chris Blank- “Environmental Problems With Plastic” 4. 5. HGCA magazine 2013, Agriculture and Horticulture Department Chapter 3 1. “The history of bioplastics” 2. -Amy Taylor, “Bioplastics Could Be The Material Of The Future” 3. Zero Waste America. (1988-2008). Waste and Recycling: Data, Maps, & Graphs. 4. Fca0TU - David Guion, “Plastic and environmental problems” 5. html- Joanne & Stefanie's Plastics Website- “History Of Plastics” 6. Chris Blank- “Environmental Problems With Plastic” 7. HGCA, “Industrial uses for crops: Bioplastics” 8. Huffington Post, Susanne Rust -“Bioplastics Debate: Could They Harm The Environment?” 9. NatureWorks LLC 10. Mater-Bi La Bioplastica 11. Beth Terry, “What’s Plastic Got To Do With Clean Air? “
  75. 75. 75 12. seas.html- Carolyn Barry, National Geographic- “Plastic Breaks Down in Ocean, After All -- And Fast” 13. European bioplastics 2013, facts and figures. 14. Introduction to bioplastics, Dr. Jim Lunt 15. European Bioplastics 16. 17. HGCA magazine 2013, Agriculture and Horticulture Department 18. NEC Research and Development: Bioplastics 19. Trends in Japan, Science & Technology-“BIOPLASTIC, Eco-Friendly Material Has a Bright Future” 20. packaging- Charlotte Wagner “Extending the use of bioplastics in food packaging” 21. bioplastics MAGAZINE [01/09] Vol. 4, Dr. Rainer Hagen 22. European bioplastics Factsheet, august 2012 23. Biome Bioplastics 24. Flex.jpg- F. Kesselring, FKuR Willich- “Mulch Film made of PLA-Blend Bio-Flex” 25. Jung, Yu Kyung; Kim, Tae Yong (2009). "Metabolic Engineering of Escherichia coli for the production of Polylactic Acid and Its Copolymers". Biotechnology and Bioengineering 105 26. Bacterially Produced Polyhydroxyalkanoate (PHA): Converting Renewable Resources into Bioplastics -Jiun-Yee Chee1, Sugama-Salim Yoga1 , Nyok-Sean Lau1 , Siew-Chen Ling1 , Raeid M. M. Abed2 and Kumar Sudesh1 27. Ya- Jane Wang, Van- Den Truong, Linfeng Wang(2002): Structures and rheological properties of corn starch as affected by acid hydrolysis. Carbohydrate Polymers 52( 2003) 327-333 28. S.A.Roberts, R.E.Cameron (2001): The effects of concentration and sodium hydroxide on the rheological properties of potato starch gelatinisation. Carbohydrate Polymers 50(2002) 133-142