Biodegradable Polymers

- “A Rebirth Of Plastics”By:-

CHITRANSH JUNEJAB.Tech (Plastic Technology), Final Year

Central Institute of Plastics Engineering & Technology (CIPET),LucknowMinistry of Chemicals & Fertilizers

Government Of India

CONTENTS : Introduction Brief History What are Biodegradable Polymers ? Types Of Biodegradable Polymers Applications Biodegradable Polymers VS

Conventional Polymers Current Scenario Future Of Biodegradable Polymers Conclusions

IntroductionPlastics are being used all over the world. From drinking cups and disposable silverware to parts for automobiles and motorcycles, plastics are continuing to rise. Plastics have been an environmental threat because of the lack of degradation. Plastics make up about 20% by volume waste per year. There are over 21,000 plastics facilities in the US, and the employment rate has increased by an average of three percent over the past two and a half decades. Plastics are extremely important to the job market as well as packaging throughout the world. Since plastics are vital to people’s everyday lives, production of biodegradable plastics to make plastics more compatible with the environment is necessary.

Distribution Of Plastics In Various Sectors

Brief HistoryBiodegradable Polymers began being sparking interest during the oil crisis in 1970’s . As oil prices increased, so did the planning & creating of biodegradable materials. The 1980’s brought items such as Biodegradable Films, Sheets , & Mold forming materials. Green Materials or plant based materials have become increasingly more popular.

What are Biodegradable Polymers? 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.

Between October 1990 and June 1992, confusion as to the true definition of “biodegradable” led to lawsuits regarding misleading and deceitful environmental advertising . Thus, it became evident to the ASTM and ISO that common test methods and protocols for degradable plastics were needed.

To be considered compostable, three criteria must be met: 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 non-toxicity.

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.

I• Conventional plastics are resistant to biodegradation, as the surfaces in contact with the soil in which they are disposed are characteristically smooth.

• Microorganisms within the soil are unable to consume a portion of the plastic.

• This group of materials usually has an impenetrable petroleum based matrix, which is reinforced with carbon or glass fibers.

II• The second class of polymer materials under consideration is partially degradable.

• 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.

III• 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 microbial 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. • 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 60oC. 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).

Types Of Biodegradable Polymers

Biodegradable Polymers are basically divided into two main classes :-

Naturally Occurring Biodegradable Resins

Biodegradable Synthetic Resins.

Naturally Occurring Biodegradable Resin

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 cornPolyesters – 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.

The range of degradable plastics now available includes:Starch-based products including thermoplastic starch, starch and synthetic Aliphatic polyester blends, and starch. Naturally produced polyesters. Renewable resource polyesters such as PLA. Synthetic aliphatic polyesters . Aliphatic-aromatic (AAC) co polyesters.Hydro-biodegradable polyester such as modified PET.Water soluble polymer such as polyvinyl alcohol and ethylene vinyl alcohol. Photo-degradable plastics. Controlled degradation additive master batches

Applications of Biodegradable Polymers

Packaging Sector :-

• It is estimated that 41% of plastics are used in packaging, and that almost half of that volume is used to package food products.

• All levels of government, particularly in China and Germany , 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.

BASF, a world leader in the chemical and plastic industry, is working on further development of biodegradable plastics based upon polyester and starch. 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. 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 .

Biobags been used as Trash Bags or for Packaging

The Biobag is made up of cornstarch, biodegradable and compostable polyester and vegetable oil and is 100% biodegradable and 100% compostable.

Biodegradable Polymers in different Packaging Areas

Agricultural Sector

- 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.

- Fertilizer and chemical storage bags which are biodegradable are also applications that material scientists have examined.

Biodegradable Polymers in Agricultural Sector

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. - 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.

Medical Applications of Biodegradable Polymers

Use of Biodegradable Polymers as Scaffolds for growing artificial Bladders.

Biodegradable Polymeric Bandages

Automobile Sector

- Natural fibres are substituted for glass fibres as reinforcement materials in plastic parts of automobiles and commercial vehicles.

- 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.

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.

STATISTICAL DATA ON USE OF BIODEGRADABLE POLYMERS AROUND THE WORLD AND IN INDIA:-

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.

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.

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.

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.

In the years 2000 to 2008, worldwide consumption of biodegradable plastics based on starch, sugar, and cellulose - so far the three most important raw materials - has increased by 600 %.As predicted global annual capacity would grow more than six-fold to 2.1 million tonnes by 2013.BCC Research forecasts the global market for biodegradable polymers to grow at a compound average growth rate of more than 17 percent through 2012.

BIODEGRADABLE POLYMERS OVER CONVENTIONAL PLASTICS

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 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. Laws of supply and demand state that increasing demand will drive costs down. The world's production of plastics will surpass 300 million tons by the end of this year, 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.

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. 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.

Challenges Ahead…Acceptance of biodegradable polymers is likely to depend on four unknowns:

Customer response to costs that today is generally 2 to 4 times higher than for

Conventional polymers;Possible legislation (particularly concerning

polymers); The achievement of total biodegradability; andThe development of an infrastructure to collect,

accepts, and process biodegradable polymers as a generally available option for waste disposal. They will require separate collection, involvement of the general public, greater community responsibility in installing recycling systems, etc. Biodegradability is tied to a specific environment. For instance, the usual biodegradation time requirement for bioplastic to be composted is 1 to 6 months.

Future Of Biodegradable Polymers

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. 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.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 year.

ConclusionsFrom 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 up growing 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 eco friendly, greener and user friendly