1

A PROJECT REPORT ON

“BIOPLASTICS- UTILIZATION OF

WASTE BANANA PEELS FOR

SYNTHESIS OF POLYMERIC FILMS”

Submitted by:

ABHIJIT MOHAPATRA

SHRUTI PRASAD

HEMANT SHARMA

SHRI VILE PARLE KELAVANI MANDAL’S

D.J.SANGHVI COLLEGE OF ENGINEERING

VILE PARLE (W), Mumbai-400056

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

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

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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

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.

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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

Chapter 1

Literature Survey

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.

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Chapter 2

Plastics

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

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

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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

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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

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

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

Chapter 3

Bioplastics

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

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

The table below gives a short comparison of various properties of both the plastics. [17]

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

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Event Date: Event:

was left was polyethylene. They were credited with the discovery of the

polymerization process.

13

th 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]

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3.3 Life Cycle

The figure below shows the lifecycle of a generic bioplastic.

[2]

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.

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[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

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

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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

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[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

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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

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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.

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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.

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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

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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

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.

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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

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

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

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

Chapter 4

Experimental

Procedure

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

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

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

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

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

Chapter 5

Testing Procedure

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

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

Chapter 6

Experimental Trials

Conducted

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

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

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

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

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

Chapter 7

Observations

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

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

Chapter 8

Calculations

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

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

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

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

Chapter 9

Analysis

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

Ten

sile

Str

en

gth

(N

/mm

^2)

Residence time (mins)

Tensile Strength Vs Residence Time

Neutral

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

Ten

sile

Str

en

gth

(N

/mm

^2)

Residence time (mins)

Tensile strength Vs Residence Time

Basic

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

Ten

sile

Str

en

gth

(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

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

% C

on

vers

ion

Residence Time

Conversion Vs Residence Time (Combined)

Acidic

Basic

Neutral

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 forDifferent PlasticisersTensile Strength(N/mm^2)

0 10 20 30 40 50

Glycerine

Sorbitol

PEG

Conversion For Different Plasticizers

Conversion %

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

Chapter 10

Preliminary Process

Scheme

69

Preliminary Process Scheme

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

Chapter 11

Future Scope

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

Chapter 12

References

74

Chapter 2

1. http://dwb.unl.edu/Teacher/NSF/C06/C06Links/qlink.queensu.ca/~6jrt/chem210/Page2.h

tml- Joanne & Stefanie's Plastics Website- “History Of Plastics”

2. http://eco.allpurposeguru.com/2011/06/plastic-and-environmental-problems/#.U1tq-

Fca0TU - David Guion- “Plastic and environmental problems”

3. http://www.ehow.com/about_5045721_environmental-problems-plastic.html- Chris

Blank- “Environmental Problems With Plastic”

4. http://en.wikipedia.org/wiki/Plastic

5. HGCA magazine 2013, Agriculture and Horticulture Department

Chapter 3

1. http://www.timetoast.com/timelines/65909- “The history of bioplastics”

2. http://htpoint.com/featured-news/bioplastics-material-future/ -Amy Taylor, “Bioplastics

Could Be The Material Of The Future”

3. Zero Waste America. (1988-2008). Waste and Recycling: Data, Maps, & Graphs.

http://zerowasteamerica.org/Statistics.htm

4. http://eco.allpurposeguru.com/2011/06/plastic-and-environmental-problems/#.U1tq-

Fca0TU - David Guion, “Plastic and environmental problems”

5. http://dwb.unl.edu/Teacher/NSF/C06/C06Links/qlink.queensu.ca/~6jrt/chem210/Page2.

html- Joanne & Stefanie's Plastics Website- “History Of Plastics”

6. http://www.ehow.com/about_5045721_environmental-problems-plastic.html- Chris

Blank- “Environmental Problems With Plastic”

7. HGCA, “Industrial uses for crops: Bioplastics”

8. http://www.huffingtonpost.com- Huffington Post, Susanne Rust -“Bioplastics Debate:

Could They Harm The Environment?”

9. http://www.natureworksllc.com- NatureWorks LLC

10. http://www.materbi.com/- Mater-Bi La Bioplastica

11. http://www.momscleanairforce.org/whats-plastic-got-to-do-with-clean-air/- Beth Terry,

“What’s Plastic Got To Do With Clean Air? “

75

12. http://news.nationalgeographic.co.in/news/2009/08/090820-plastic-decomposes-oceans-

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. http://en.european-bioplastics.org/standards/certification/- European Bioplastics

16. http://www.eurokamczech.com/Biokam/Biokam/web/Packaging%C2%A0.html

17. HGCA magazine 2013, Agriculture and Horticulture Department

18. http://www.nec.com/en/global/environment/featured/bioplastics/- NEC Research and

Development: Bioplastics

19. http://web-japan.org/trends/science/sci031212.html- Trends in Japan, Science &

Technology-“BIOPLASTIC, Eco-Friendly Material Has a Bright Future”

20. http://www.foodpackagingforum.org/Research/Extending-the-use-of-bioplastics-in-food-

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. http://www.biomebioplastics.com/- Biome Bioplastics

24. http://commons.wikimedia.org/wiki/File:Mulch_Film_made_of_PLA-Blend_Bio-

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 Lau

1, Siew-Chen

Ling1, Raeid M. M. Abed

2 and Kumar Sudesh

1

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