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Biodegradable Polymers “A Rebirth of Plastics”

CHITRANSH JUNEJA

B.Tech (Plastic Technology), Final Year Central Institute of Plastics Engineering & Technology (CIPET)

Department of Chemicals& Petrochemicals, Ministry of Chemicals & Fertilizers

Govt. Of India Lucknow, INDIA

chitranshjuneja@ymail.com Abstract— In recent years, there has been a marked increase in interest in biodegradable materials for use in packaging, agriculture, medicine, and other areas in India. In particular, biodegradable polymer materials (known as biocomposites) are of interest. Polymers form the backbones of plastic materials, and are continually being employed in an expanding range of areas. As a result, many researchers are investing time into modifying traditional materials to make them more user-friendly, and into designing novel polymer composites out of naturally occurring materials. A number of biological materials may be incorporated into biodegradable polymer materials, with the most common being starch and fiber extracted from various types of plants. The belief is that biodegradable polymer materials will reduce the need for synthetic polymer production (thus reducing pollution) at a low cost, thereby producing a positive effect both environmentally and economically. This paper is intended to provide a brief outline of work that is under way in the area of biodegradable polymer research and development, the scientific theory behind these materials, areas in which this research is being applied, and the major advantages of these biodegradable polymer materials in India.

Keywords: biopolymer, biodegradable, plastic, agricultural products, biomaterial, recycling, life cycle assessment, environmental impact, economic impact, composite

I. INTRODUCTION

Advanced technology in petrochemical polymers has brought many benefits to mankind. However, it becomes more evident that the ecosystem is considerably disturbed and damaged as a result of the non-degradable materials for disposable items. As we listen daily that Plastics is doing harm to environment, it is disturbing our natural habitat, ecosystem, since we know this is true but this is also a fact that Life without plastics is also not possible for we the humans. We for our necessities have to go for plastics. So we have to go for an alternative to plastics , which isn’t possible , the thing we can do is that we can make plastic greener i.e. development of Biodegradable Polymers . By developing Biodegradable Plastics we can have an edge in our very own and developing world of Plastics.

II. BRIEF HISTORY

Biodegradable plastics began being sparking interest during the oil crisis in the 1970’s. As oil prices increased, so did the planning and creating of biodegradable materials. The 1980’s brought items such as biodegradable films, sheets, and mold forming materials. Green materials (or Plant-based) have become increasingly more popular (Mohanty, 2004). This is due impart to the fact that they are a renewable resource that is much more economical then they were in the past (Mohanty, 2004).

III. WHAT ARE BIODEGRADABLE POLYMERS

The development of innovative Biopolymer materials has been underway for a no. of years and continues to be an area of interest for many scientists. The American Society for Testing of Materials (ASTM) and the International Standards Organization (ISO) define degradable plastics as those which undergo a significant change in chemical structure under specific environmental conditions. These changes result in a loss of physical and mechanical properties, as measured by standard methods. Biodegradable plastics undergo degradation from the action of naturally occurring microorganisms such as bacteria, fungi, and algae. Plastics may also be designated as photodegradable, oxidatively degradable, hydrolytically degradable, or those which may be composted. Between October 1990 and June 1992, confusion as to the true definition of “biodegradable” led to lawsuits regarding misleading and deceitful environmental advertising (Narayan et al. 1999). Thus, it became evident to the ASTM and ISO that common test methods and protocols for degradable plastics were needed. For biodegradable materials, it is generally regarded that the product will degrade into water and carbon dioxide by virtue of a naturally occurring organism, such as microorganisms. Some industry sources have offered the term compostable in place of biodegradable. To be considered compostable, three criteria must be met:

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biodegradation—it has to break down into carbon dioxide, water and biomass at the same rate as cellulose; disintegration—the plastic must become indistinguishable in the compost; and nontoxicity. Most international standards (such as ISO 17088) require at least a 60% biodegradation of a product within 180 days, along with other factors, in order to be called compostable. There are three primary classes of polymer materials which material scientists are currently focusing on. These polymer materials are usually referred to in the general class of plastics by consumers and industry. Their design is often that of a composite, where a polymer matrix (plastic material) forms a dominant phase around a filler material (Canadian Patent #2350112- 2002). The filler is present in order to increase mechanical properties, and decrease material costs. Conventional plastics are resistant to biodegradation, as the surfaces in contact with the soil in which they are disposed are characteristically smooth (Aminabhavi et al. 1990). Microorganisms within the soil are unable to consume a portion of the plastic, which would, in turn, cause a more rapid breakdown of the supporting matrix. This group of materials usually has an impenetrable petroleum based matrix, which is reinforced with carbon or glass fibers. The second class of polymer materials under consideration is partially degradable. They are designed with the goal of more rapid degradation than that of conventional synthetic plastics. Production of this class of materials typically includes surrounding naturally produced fibers with a conventional (petroleum based) matrix. When disposed of, microorganisms are able to consume the natural macromolecules within the plastic matrix. This leaves a weakened material, with rough, open edges. Further degradation may then occur. The final class of polymer materials is currently attracting a great deal of attention from researchers and industry. These plastics are designed to be completely biodegradable. The polymer matrix is derived from natural sources (such as starch or microbially grown polymers), and the fiber reinforcements are produced from common crops such as flax or hemp. Microorganisms are able to consume these materials in their entirety, eventually leaving carbon dioxide and water as by-products. Materials must meet specific criteria set out by the ASTM and ISO in order to be classified as biodegradable. In general, the likelihood of microbial attack on a material is dependent on the structure of the polymer. When examining polymer materials from a scientific standpoint, there are certain ingredients that must be present in order for biodegradation to occur. Most importantly, the active microorganisms (fungi, bacteria, actinomycetes, etc.) must be present in the disposal site. The organism type determines the appropriate degradation temperature, which usually falls between 20 to 60 0C (Shetty et al. 1990). The

disposal site must be in the presence of oxygen, moisture, and mineral nutrients, while the site pH must be neutral or slightly acidic (5 to 8). Thus, we can conclude Biodegradable Polymers as “ The polymeric material which is capable of being broken into simpler units such as carbon dioxide, water etc. after exposure of material into certain environmental conditions, or by attack of microorganisms such as fungi, algae, & bacteria.” Now after gaining basic understanding of what Biodegradable Polymer is we should get onto our next step i.e. “Types Of Biodegradable Polymers”

III. TYPES OF BIODEGRADABLE POLYMERS

Biodegradable Polymers are divided into two classes mainly:-

i. Naturally Occurring Biodegradable Resins

ii. Biodegradable Synthetic Resins

Naturally Occurring Biodegradable Resins

This category of material includes:

• Polysaccharides e.g.- Starch from potatoes and corn.

• Proteins e.g. –Gelatin, Casein from Milk, Keratin from silk and wool, Zein from corn

• Polyesters – Polyhydroxy alkanoates formed by lignin, shellac, prolactic acid

• Materials such as jute, flux , cotton, silk.

Biodegradable Synthetic Resin

While there are number of degradable synthetic resins, including: polyalkylene , esters , polylactic acid polyamide esters , polyvinyl acetate, polyvinyl alcohol, polyanhydrides. The materials mentioned here are those that exhibit degradation promoted by micro-organisms. This has often been coupled to a chemical or mechanical degradation step.

IV. APPLICATIONS OF BIODEGRADABLE POLYMERS

PACKAGING.

Biopolymers that may be employed in packaging continue to receive more attention than those designated for any other application. All levels of government, particularly in

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China (Chau et al. 1996) and Germany (Bastioli 1998), are endorsing the widespread application of biodegradable packaging materials in order to reduce the volume of inert materials currently being disposed of in landfills, occupying scarce available space. It is estimated that 41% of plastics are used in packaging, and that almost half of that volume is used to package food products. BASF, a world leader in the chemical and plastic industry, is working on further development of biodegradable plastics based upon polyester and starch (Fomin et al. 2001). Ecoflex is a fully biodegradable plastic material that was introduced to consumers by BASF in 2001. The material is resistant to water and grease, making it appropriate for use as a hygienic disposable wrapping, fit to decompose in normal composting systems. Consequently, Ecoflex has found a number of applications as a packaging wrap.

Environmental Polymers (Woolston, Warrington, UK) has also developed a biodegradable plastic material. Known as Depart, the polyvinyl alcohol product is designed for extrusion, injection molding, and blow molding. Depart features user-controlled solubility in water, which is determined by the formulation employed. Dissolution occurs at a preset temperature, allowing the use of Depart in a variety of applications. Examples include hospital laundry bags which are “washed away” allowing sanitary laundering of soiled laundry, as well as applications as disposable food service items, agricultural products, and catheter bags (Blanco 2002).

AGRICULTURAL APPLICATIONS Agricultural applications for biopolymers are not limited to film covers. Containers such as biodegradable plant pots and disposable composting containers and bags are areas of interest (Huang 1990). The pots are seeded directly into the soil, and breakdown as the plant begins to grow. Fertilizer and chemical storage bags which are biodegradable are also applications that material scientists have examined. From an agricultural standpoint, biopolymers which are 7 compostable are important, as they may supplement the current nutrient cycle in the soils where the remnants are added.

MEDICAL APPLICATIONS

The medical world is constantly changing, and consequently the materials employed by it also see recurrent adjustments. The biopolymers used in medical applications must be compatible with the tissue they are found in, and may or may not be expected to break down after a given time period. Mukhopadhyay (2002) reported that researchers working in tissue engineering are attempting to develop organs from polymeric materials, which are fit for transplantation into humans. The plastics would require injections with growth factors in order to encourage cell and blood vessel growth in the new organ. Work completed in this area includes the

development of biopolymers with adhesion sites that act as cell hosts in giving shapes that mimic different organs. AUTOMOBILE SECTOR The automotive sector is responding to societal and governmental demands for environmental responsibility. Biobased cars are lighter, making them a more economical choice for consumers, as fuel costs are reduced. Natural fibres are substituted for glass fibres as reinforcement materials in plastic parts of automobiles and commercial vehicles (Lammers and Kromer 2002). An additional advantage of using biodegradable polymer materials is that waste products may be composted. Natural fibres (from flax or hemp) are usually applied in formed interior parts. The components do not need load bearing capacities, but dimensional stability is important. Research and development in this area continues to be enthusiastic, especially in European countries.

MISSELANEOUS APPLICATIONS

• Mulch film from biodegradable plastics This kind of mulch film can be useful for farmers. Mulch films are laid over the ground around crops, to control weed growth and retain moisture. Normally, farmers use polyethylene black plastic that is pulled up after harvest and trucked away to a landfill (taking with it topsoil humus that sticks to it). However, field trials using the biodegradable mulch film on tomato and chilly crops have shown it performs just as well as polyethylene film but can simply be ploughed into the ground after harvest. It’s easier, cheaper and it enriches the soil with carbon.

• Plantable Pots Another biodegradable plastic product is a plant pot produced by injection moulding. Gardeners and farmers can place potted plants directly into the ground, and forget them. The pots will break down to carbon dioxide and water, eliminating double handling and recycling of conventional plastic containers. BIODEGRADABLE POLYMERS AS COMPOSITES:- - According to Prashant Yadav, of Tata Technologies LTD, today Tata Motors are using Biodegradable Composites in there cars door trim, we can see its example in Indica Vista only. - Toyota Moto Corp. became the first automaker in the world to use bioplastics in the manufacture of auto parts, employing them in the cover for the spare tire in the new. - Mitsubishi Motors Develops ‘Green Plastic’ , Bamboo-Fibre Reinforced Plant-based Resin for use in Automobile Interiors; Cutting CO2 emissions Throughout the vehicle Lifecycle Tokyo, Japan, Feb 17,2006. - Jute based bio-composite material is used in Parcel Shelf in NANO and hood & firewall insulation in VISTA. - Ford intend to replace 405 of Petroleum Based Polyol to be replace with soya derived material. Ford Flex – this crossover utility vehicle will be the first to have in its interior wheat straw- reinforce plastic as part of the third-row interior storage bins.

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In this way we can say that Biodegradable Polymers are having wide range of applications, few of them are stated above and many more can be listed.

V. CURRENT SCENARIO

There is room for growth and expansion in many areas of the biodegradable plastic industry. Chau et al. (1999) estimates that plastic waste generation will grow by 15% per year for the next decade. Carbon dioxide emissions from the formation and disposal of conventional plastics are reaching epic levels. The complete substitution of petroleum-based feedstock plastics by renewable resource-based feedstock ones would lead to a balanced carbon dioxide level in the atmosphere (Dahlke et al. 1998). However, it is ludicrous to expect a full replacement of conventional polymers by their biodegradable counterparts any time soon. Expansion into particular niche markets seems to be the most viable option. Researchers worldwide are interested in the area of biopolymer development. The German government has stringent regulations in place regarding acceptable emission levels. In 1990, the German government published a call for research and development of biodegradable thermoplastics (Grigat et al. 1998). For this reason, many German material scientists and engineers have focused their work on environmentally stable biodegradable plastics. Various materials have been created by these researchers, including the Bayer BAK line which was introduced in extrusion and injection moulding grades in 1996. Novamont, an Italian company, introduced the Mater-Bi line for similar reasons. Queen Mary University in London, England has a plastics department which is actively working on biocomposite development (Hogg 2001). As a whole, all European nations are expected to follow the European Packaging directive, which expects a material recovery of packaging waste. Organic recovery (composting spent materials) is the most commonly applied waste reduction method (Schroeter 1998). European nations are also expected to incorporate 15% w/w of recycled plastics into the manufacture of packaging materials. Germany aims to better that level, as they set tier goal in 2001 for a 60% incorporation of recycled plastics into new packaging materials (Fomin et al. 2001). European nations are the front runners of biopolymer research, but impressive developmental work has occurred, and continues to occur, in other geographical areas. The Chinese government is responsible for a large population on a small land base. Therefore, the preservation of space, and responsible disposal of waste are key considerations. For these reasons, Chinese researchers are focusing on refinement of microbially produced PHA (Chau et al. 1996). North American researchers, including those at the University of Saskatchewan, are also interested in biopolymer development, as the agricultural industry will benefit from the potential value added processing. The acceptance of the Kyoto Accord by the Government of Canada is fueling a need for the reduction of use of fossil fuel feedstock’s, and an increase in the use of renewable resource feedstock’s. Biodegradable plastics fulfill this requirement.

Standards organizations such as the ASTM and ISO have published methods for material tests on biodegradable plastic materials. A need for reviews and improvements of these tests has come to light as industry expands its use of biopolymers. In particular, non-homogeneities are created in polymer materials by the clamps used for tensile tests (Nechwatal et al. 2003). The nature of natural materials requires different considerations than those for synthetic materials. Thus Biodegradable Polymers have achieved several targets and several milestones are yet to be crossed, thus researches are on and scientists are doing their best to make plastic greener and more greener.

VI. STATISTICAL DATA ON USAGE OF BIODEGRADABLE POLYMERS

(i) Despite the poor global economy, the biodegradable polymers market grew in 2009 and will continue to expand at an average annual rate of 13% through 2014, says report.

(ii) The report adds that the single-largest end use for this material will be the “food packaging, dish, and cutlery market,” which it says “will be the major growth driver in the future.”

(iii) Despite the economic crisis, which hit the chemical and plastics industry, the market for biodegradable polymers did grow in 2009 in almost all regions. In Europe, the largest global market, growth was in the range of 5% to 10%, depending on products and applications, compared with 2008.

(iv)Europe continues to be the largest biodegradable polymers-consuming region, with about half of the global total. Major market drivers for biodegradable polymers in this region include legislation, depleting landfill capacities, pressure from retailers, growing consumer interest in sustainable plastic solutions, fossil oil and gas independence, and the reduction of greenhouse gas emissions.

(v) In Japan, there has been some growth in biodegradable polymers use as a result of government and industry promoting their use. The rising prices for petroleum and petroleum-based products have also contributed to the replacement of petroleum-based polymers with biodegradable polymers. However, Japanese consumption of biodegradable polymers has not increased as much as expected.

(vi) In Other Asian countries, biodegradable polymer demand is expected to increase greatly in the next several years. In China, high growth will be due to several factors: an increase in production capacity, demand for environmentally friendly products, and the government’s plastic waste control legislation.

(vii) Because of the fragmentation in the market and ambiguous definitions it is difficult to describe the total market size for bioplastics, but estimates put global production

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capacity at 327,000 tonnes.[26] In contrast, global consumption of all flexible packaging is estimated at around 12.3 million tonnes.

(viii) COPA (Committee of Agricultural Organization 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.

(ix) Other data’s are as follows:- - Catering products: 450,000 tonnes per year - Organic waste bags: 100,000 tonnes per year - Biodegradable mulch foils: 130,000 tonnes per year - Biodegradable foils for diapers 80,000 tonnes per

year - Diapers, 100% biodegradable: 240,000 tonnes per

year - Foil packaging: 400,000 tonnes per year - Vegetable packaging: 400,000 tonnes per year - Tyre components: 200,000 tonnes per year - Total 2,000,000 tonnes per year

VII. BIODEGRADABLE VS CONVENTIONAL POLYMERS

Biodegradable materials are beginning to be accepted in many countries. These materials are thought to help the environment by reducing waste issues. The two main reasons for using biodegradable materials, according to Mohanty are, “the growing problem of waste resulting in the shortage of landfill availability and the need for the environmentally responsible use of resources”. As the government and many organizations are working to save the environment, there is a definite advantage to making biodegradable plastics more of a reality. Conventional plastics have widespread use in the packaging industry because biodegradable plastics are cost prohibitive. The key, bringing the costs down, is to have numerous companies buy a large sum of biodegradable materials. Laws of supply and demand state that increasing demand will drive costs down. Like conventional plastics, biodegradable plastics must have the same structural and functional qualities, in addition to reacting the same as conventional plastics when used by the consumer. The biodegradable plastics also must be inclined to, “microbial and environmental degradation upon disposal, without any adverse environmental impact” (Mohanty, 2004) The world's production of plastics will surpass 300 million tons by the end of this year, Halden writes, consuming 8 percent of the world's annual oil production. Approximately a third of those plastics are used in disposable goods like takeout containers, plastic bags, and product packaging, leading to a pretty huge pile of plastic trash. About half a pound of plastic trash is produced per person per day, and the

disposal of all that garbage is creating huge problems, considering that most municipalities recycle only two out of dozens of types of plastic. Non-recycled plastics wind up in landfills or, increasingly, in the Great Pacific Garbage Patch, a swath of ocean the size of Texas in the North Pacific completely covered with trash, most of which is plastic. If plastics don't wind up in landfills or the ocean, they're incinerated, releasing cancer-causing compounds called dioxins and furans into the atmosphere. But the disadvantages of plastic go beyond its environmental impact. More and more research is finding that the chemical additives in plastics— used to make plastics harder or softer, to keep them from breaking down too quickly when exposed to light and heat, and to keep them from absorbing bacteria—are causing severe human health problems. The two most researched, and worrisome, additives are BPA and phthalates. BPA is a hormone-disrupting chemical used to keep polycarbonate plastic food containers rigid, but it has been linked to a variety of problems, including obesity, early puberty in girls (which itself is a precursor to obesity), decreased levels of testosterone and lowered sperm counts in men, lowered immune responses, and aggressive behavior in children—all at levels lower than what the EPA deems "safe." Like BPA, phthalates are hormone disruptors, though they're used to keep plastics—usually vinyl—soft and pliable. They've been definitively linked to increased rates of asthma, and a number of studies have found they interfere with male reproductive development and could possibly play a role in obesity and insulin resistance. While phthalates have been banned in products marketed to children, they're still widely used in other household products, such as shower curtains and vinyl flooring, as well as medical products like IV bags and medical tubing.

VIII. CHALLENGES AHEAD

Acceptance of biodegradable polymers is likely to depend on four unknowns: (1) Customer response to costs that today is generally 2 to 4 times higher than for conventional polymers; (2) Possible legislation (particularly concerning water-soluble polymers); (3) The achievement of total biodegradability; and (4) The development of an infrastructure to collect, accepts, and process biodegradable polymers as a generally available option for waste disposal. In a social context biodegradable plastics call for a re-examination of life-styles. They will require separate collection, involvement of the general public, greater community responsibility in installing recycling systems, etc. On the question of cost, awareness may often be lacking of the significance of both disposal and the environmental costs, which are to be added to the processing cost. Biodegradability is tied to a specific environment. For

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instance, the usual biodegradation time requirement for bioplastic to be composted is 1 to 6 months. The development of starch-based biodegradable plastics looks very promising given the fact that starch is inexpensive, available annually, biodegradable in several environments and incinerable. The main drawbacks the industry is running into are bioplastics' low water-barrier and the migration of hydrophilic plasticizers with consequent ageing phenomena. The first problem together with the cost factor is common to all other biodegradable plastics. These challenges have to be faced and solved accordingly to enter the niche market. Challenges and oppurtunities in India: According to Mr.Sunder Balakrishnan of Harita NTI LTD, Chennai, In recent years, a combination of market drivers such as higher petroleum prices, a desire to reduce dependence on foreign oil, increased environmental awareness at the consumer level, and favorable regulations banning the use of regular plastics, have led to widespread interest in sustainable, renewable resource based and compostable alternatives to traditional plastics. This presentation explores the key opportunities and challenges for adoption of biodegradable and biobased plastics in India, and provides an overview of the products and applications for bio plastics. The specific areas covered will include: Implementation of Sustainable Packaging initiatives from major corporates in driving the need for innovative, environmentally friendly packaging solution. Increasing concern about the impact of Global Warming and the need to reduce Green House Gas (GHG) emissions, and how that is prompting companies to replace conventional plastics made from petroleum feedstock with plastics made from bio feedstocks/renewable resources. Examples of products and applications will demonstrate the value proposition for biobased plastics. Need for “zero waste” organics diversion programs as a way to deal with waste management issues. A case study will highlight the importance of integrating the use of biodegradable plastics with appropriate end-of-life disposal methods to implement sustainable, cost effective waste management programs Thus we can say there is very emergent situation in need of Biodegradable Polymers.

IX. FUTURE OF BIODEGRADABLE POLYMERS

The future of biodegradable plastics shows great potential. Many countries around the world have already begun to integrate these materials into their markets. The Australian Government has paid $1 million dollars to research and develop starch-based plastics. Japan has created a biodegradable plastic that is made of vegetable oil and has the same strength as traditional plastics. The mayor of Lombardy, Italy recently announced that merchants must make

biodegradable bags available to all of their customers. In America, McDonald’s is now working on making biodegradable containers to use for their fast food (“Plastics”, 1998). Other companies such as Bayer, DuPont, and Dow Cargill are also showing interest in biodegradable packaging. According to Dr. Mohanty, “demands for biodegradables are forecast to grow nearly 16% per annum.” This increasing interest will allow the technology needed to produce biodegradable plastics became more affordable and the falling production costs will eventually lead to an increase in producers (“Plastics”, 1998). America and Japan show the greatest potentials for the biodegradable markets. The estimated amount of biodegradable plastics produced per year is about 30,000-40,000 tons over the next five years (Mohanty, 2004).

X. CONCLUSIONS

From the long discussions and studying several data’s and researches , there is no hesitation in accepting the fact that Biodegradable polymer are giving a solid edge to growing Plastic industry of today. As we know that prices of Petroleum products are on a hike, and also on the way to scarcity , since plastic is also a product of petroleum therefore at this moment of time Biodegradable Polymers are emerging as miracle to upgrowing Plastic Industry. In addition to that Plastic is facing a terrible opposition from society due to its non degradability and causing hazards to this beautiful nature & to human too as stated previously. Biodegradable Polymers don’t only fulfill the purpose of degradability but also gives Plastic Industry a new positivity. Development of Biodegradable Polymers makes plastic more ecofriendly, greener and user friendly.

ACKNOWLEDGMENT

I would specially like to thank Dr. Vijai Kumar, Professor & Centre Head, Higher Learning Centre, Central Institute of Plastics Engineering & Technology (CIPET), Lucknow for his kind support and guidance for preparation of this paper. My vote of thanks next goes to all faculty members without whom this was an difficult task for me.

Finally, yet importantly, I would like to express my heartfelt thanks to my beloved parents and my family for their blessings and wishes.

REFERENCES

I. “Biodegradable Polymers” by Shellie Berkesch of Michigan State university

II. “Biodegradable Polymers” by M. Kolybaba, L.G. Tabil, S. Panigrahi, W.T. Crerar, T. Powell, B. Wang of University of Sastachewan, Canada.

III. Article published in Science Tech Entrepreneur magazine August 2006 issue.

IV. “Biodegradable Polymers” by A. Ashwin Kr. , Karthick K, & A. Arumugum.

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