The document discusses biopolymers, which are polymers produced by living organisms. It covers various types of biodegradable polymers including synthetic polymers like polylactic acid (PLA) and natural polymers like starch. The mechanisms of polymer biodegradation are described. Applications of biodegradable polymers in areas like biomedical, packaging and agriculture are also mentioned. Factors affecting the biodegradation of polymers are discussed. Current trends in biopolymers including their use as alternatives to petroleum-based plastics are summarized.

1. BIOPOLYMER
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2. CONTENTS
 Introduction of polymers.
 Biodegradable polymers.
 Classification of biodegradable polymers.
 Polymer Degradation mechanisms
a) Bioerosion mechanism.
b) Enzymatic or chemical degradation.
 Synthetic biodegradable polymers.
 Natural biodegradable polymers.
 Factors affecting biodegradation of polymers.
 Applications of biodegradable polymers.
 Conclusion.
 References.
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3. BIOPOLYMER
 The term "polymer" derives from the ancient Greek word
polus, meaning "many, much" and meros meaning "parts", and
refers to a molecule whose structure is composed of multiple
repeating units.
 The term was coined in 1833 by Jons Jacob Berzelius.
 Biopolymers are polymers produced by living organisms.
 Since they are polymers, biopolymers contain monomeric
units that are covalently bonded to form larger structures.
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4. BIOPOLYMERS AS MATERIALS
 Some biopolymers- such as Polylactic acid (PLA),
naturally occurring, and poly-3-hydroxybutyrate (PHB)
can be used as plastics, replacing the need for polystyrene
or polyethylene based plastics.
 Some plastics are now referred to as being 'degradable',
'oxy-degradable' or 'UV-degradable'. This means that they
break down when exposed to light or air, but these plastics
are still primarily (as much as 98 per cent) oil-based and are
not currently certified as 'biodegradable' under certain
international laws.
 Biopolymers, however, will break down and some are
suitable for domestic composting.
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5. BIODEGRADABLE POLYMERS
 Biodegradable polymers are defined as polymers
comprised of monomers linked to one another
through functional groups and have unstable links in
the backbone.
 They are broken down into biologically acceptable
molecules that are metabolized and removed from
the body via normal metabolic pathways.
 Based on biodegradability polymers are classified as:
1. Biodegradable polymers
eg: collagen, poly glycolic acid etc.,
2. Non biodegradable polymers
eg: poly vinyl chloride, polyethylene etc.,
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6. CHARACTERISTICS OF AN IDEAL
POLYMER
 Should be versatile and possess a wide range of
mechanical, physical, chemical properties.
 Should be non-toxic and have good mechanical
strength and should be easily administered.
 Should be inexpensive
 Should be easy to fabricate.
 Should be inert to host tissue and compatible with
environment.
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7. CLASSIFICATION OF BIODEGRADABLE
POLYMERS
BIOPOLYMERAGROPOLYMER
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9. POLYMER DEGRADATION
 Polymer degradation is a change in the properties
 The term 'biodegradation' is limited to the description of
chemical processes
 ‘Bioerosion' may be restricted to refer to physical
processes that result in weight loss of a polymer device.
 The bioerosion of polymers is basically of two types :-
1) Bulk erosion
2) Surface erosion
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10. TYPES OF BIOEROSION
1) Bulk erosion
• Degradation takes place throughout
the whole of the sample.
• Ingress of water is faster than the
rate of degradation
Eg : Polylactic acid (PLA)
Polyglycolic acid (PGA)
2) Surface erosion
• Sample is eroded from the surface.
• Mass loss is faster than the ingress
of water into the bulk.
Eg: Polyanhydrides ,
Polyorthoesters
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11.  Chemical or enzymatic degradation – It is mediated
by water, enzymes, microorganisms.
TRANSFORMATION OF SIDE CHAINS
CLEAVAGE OF CROSSLINKS
CLEAVAGE OF BACKBONE
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12. CLASSIFICATION OF BIODEGRADABLE
POLYMERS BASED ON THE SOURCE
1) Synthetic biodegradable polymers:
eg: Aliphatic poly(esters)
Polyanhydrides
Polyphosphazenes
polyaminoacids
Poly orthoesters etc.,
2) Natural biodegradable polymers:
eg: Albumin
Collagen
Dextran
Gelatin
Pectin, starch etc.,
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13. SYNTHETIC BIODEGRADABLE POLYMERS
1) Aliphatic poly(esters)
 These are prepared by polymerization of cyclic ester.
 Aliphatic polyesters include:
a) POLY (GLYCOLIC ACID)
b) POLY (LACTIC ACID)
c)POLY (CAPROLACTONE)
POLY (GLYCOLIC ACID) ---(--O—C-CH2---)n
POLY (LACTIC ACID) --(--O---C—CH---)n
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14. SOME BIODEGRADABLE POLYMERS
Starch
Cellulose
PLA
PHB
PCL
PHA
PA
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15. POLYLACTIC ACID
 Poly(lactic acid) or polylactide (PLA) is a thermoplastic
aliphatic polyester commonly derived from renewable
resources, such as
• corn starch (in the United States),
• tapioca products (roots, chips or starch mostly in Asia) or
• sugarcanes (in the rest of world).
 It can biodegrade under certain conditions, such as the
presence of oxygen, and is difficult to recycle.
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16. POLYGLYCOLIC ACID
 Biodegradable, thermoplastic polymer and the simplest
linear, aliphatic polyester.
 It is a tough fibre-forming polymer.
 Due to its hydrolytic instability its use has been limited.
 It has a glass transition elevated degree of temperature
between 35-40ºC., crystallinity, around 45ºC.
 Degraded by hydrolysis, and broken down by certain
enzymes.
Applications
 Used to deliver drugs in the form of microspheres, implants
etc.,
 Examples of drugs delivered include steroid hormones,
antibiotics, anti cancer agents etc.,
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17. POLY LACTIC ACID (PLA)
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18. POLYLACTIC ACID
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19. POLYLACTIC ACID (PLA): BIODEGRATABILITY
 PLA is considered both as biodegradable and as
biocompatible in contact with living tissues
 PLA can be degraded by abiotic degradation. During the
biodegradation process, and only in a second step, the
enzymes degrade the residual oligomers till final
mineralization (biotic degradation).
 As long as the basic monomers (lactic acid) are produced
from renewable resources (carbohydrates) by fermentation,
PLA complies with the rising worldwide concept of
sustainable development and is classified as an
environmentally friendly material.
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20. APPLICATIONS
 Biomedical :
Sutures, dialysis media and drug delivery devices. The
total degradation time of PLA is a few years. It is also being
evaluated as a material for tissue engineering.
 Bioplastic:
Useful for producing loose-fill packaging, compost
bags, food packaging, and disposable tableware. In the form of
fibers and non-woven textiles, PLA also has many potential
uses, for example as upholstery, disposable garments,
feminine hygiene products, and diapers.
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21. Due to PLA's relatively low glass transition
temperature, PLA cups cannot hold hot
liquids. However, much research is
devoted to developing a heat resistant PLA
Mulch film made of polylactic acid
(PLA)-blend bio-flex
Biodegradable cups at a restaurant
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23. BIOPLASTICS FROM MICROORGANISMS
Benefits
• 100 % biodegradable
• Produced from natural,
renewable resources
• Able to be recycled,
composted or burned
without producing toxic
byproducts
Degradable polymers that are naturally degraded by
the action of microorganisms such as bacteria, fungi
and algae
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26. IMPORTANCE
 2003- north america
107 billion pounds of
synthetic plastics produced
from petroleum
take >50 years to degrade
improper disposal and failure
to recycle overflowing
landfills
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27. Polyhydroxyalkanoates (PHAs)
• Polyesters accumulated inside microbial cells as
carbon & energy source storage
Ojumu et al., 2004
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28. Polyhydroxyalkanoates (PHAs)
• Produced under conditions of:
– Low limiting nutrients (P, S, N, O)
– Excess carbon
 2 different types:
 Short-chain-length 3-5 Carbons
 Medium-chain-length 6-14 Carbons
 ~250 different bacteria have been found to produce
some form of PHAs
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29. Polyhydroxybutyrate (PHB)
• Short-chain-length PHA
• Produced in activated sludge
• Found in Alcaligenes eutrophus
• Accumulated intracellularly as
granules (>80% cell dry weight)
Lee et al., 1996
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30. PHB Biosynthesis
Ojumu et al., 2004
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31. PHB: polyhydroxybutyrate
Intracellular microbial plastic first found in Bacillus megaterium
80 different types of PHAs formed from 3-hydroxyalkanoate acid monomers
3-14 carbons in length
Energy store when nutrient is limited
Alcaligenes eutrophus to produce PHB
Polymer had low thermal stability and brittle
Addition of propionate to culture produced P (3HB-co-3HV)
and polymer was flexible and tough
HB: hydroxybutyrate HV: hydroxyvalerate
Marketed as BIOPOLTM used to make films, coated paper,
compost bags, disposable foodwares , bottles.
COST is still HIGHER than chemically synthesized polymers
Propylene: 1$/kg
PHVB: 3-5$/kg
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32. Recovery of PHAs from Cells
• PHA producing microorganisms stained with Sudan
black or Nile blue
• Cells separated out by centrifugation or filtration
• PHA is recovered using solvents (chloroform) to
break cell wall & extract polymer
• Purification of polymer
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33. Bioplastic Properties
• Some are stiff and brittle
– Crystalline structure  rigidity
• Some are rubbery and moldable
• Properties may be manipulated by blending
polymers or genetic modifications
• Degrades at 185°C
• Moisture resistant, water insoluble, optically pure,
impermeable to oxygen.
• Must maintain stability during manufacture and use
but degrade rapidly when disposed of or recycled
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34. Biodegradation
• Fastest in anaerobic sewage and slowest in seawater
• Depends on temperature, light, moisture, exposed
surface area, pH and microbial activity
• Degrading microbes colonize polymer surface &
secrete PHA depolymerases
• PHA  CO2 + H2O (aerobically)
• PHA  CO2 + H2O + CH4 (anaerobically)
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35. Biodegradation by
PHA depolymerases
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36. NATURAL POLYMERS
These are the polymers obtained from natural resources, and are
generally non-toxic.
Natural polymers are formed in nature during the growth cycles of
all organisms.
NATURAL POLYMERS
PROTEINS Polysaccharides
Eg: COLLAGEN
ALBUMIN
FIBRIN
Eg : DEXTRAN
CHITOSAN
STARCH
ADVANTAGES :
1) Readily & Abundantly Available.
2) Comparatively Inexpensive.
3) Non toxic products.
4) Can be modified to get semi synthetic forms.
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37. FACTORS AFFECTING BIODEGRADATION OF
POLYMERS
 Morphological factors
 Shape & size
 Variation of diffusion coefficient and mechanical stresses
 Chemical factors
 Chemical structure & composition
 Presence of ionic group and configuration structure
 Molecular weight and presence of low molecular weight
compounds
 Physical factors
 Processing condition
 Sterilization process
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38. CURRENT TRENDS IN BIOPOLYMER
 This study on biopolymers market estimates the
global demand for biopolymers and market value
for 2012 and projects the expected demand and
market value of the same by 2018.
 As a part of quantitative analysis, the study
segments the global market by type, application
and geography with current market estimation and
forecast till 2018.
 The segmentation by type includes bio-PET, bio-
PE, PLA, PHA, bio-PBS, starch blends, and
regenerated cellulose; while on the basis of its
application the segmentation includes packaging,
bottles, fibers, agriculture, automotive, injection
molding and others.
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39. APPLICATIONS OF BIODEGRADABLE POLYMERS
 Biodegradable polymer for ocular, tissue engineering, vascular,
orthopedic, skin adhesive & surgical glues.
 Bio degradable drug system for therapeutic agents such as anti
tumor, anti-inflammatory agent.
 Polymeric materials are used in and on soil to improve aeration, and
promote plant growth and health.
 Many biomaterials, especially heart valve replacements and blood
vessels, are made of polymers like Dacron, Teflon and polyurethane.
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40. APPLICATIONS FOR BIOPLASTICS,
BIOPOLYMERS
AGRICULTURE
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41. ADVANTAGES OF BIOPLASTICS
• Less energy requriment
• Low CO2 emission
• Low green house gas emission
• Low water consumption
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42. ADVANTAGES OF BIOPOLYMERS
 Localized delivery of drug
 Sustained delivery of drug
 Stabilization of drug
 Decrease in dosing frequency
 Reduce side effects
 Improved patient compliance
 Controllable degradation rate
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43. DISADVANTAGE
 Bioplastics don't always readily decompose. Some need
relatively high temperatures and can still take many years to
break down. Even then, they may leave behind toxic residues.
 Bioplastics are made from plants such as corn and maize, so
land that could be used to grow food for the world is being
used to "grow plastic" instead.
 Some bioplastics, such as PLA, are made from genetically
modified corn.
 Bioplastics cannot be easily recycled. To most people, PLA
looks very similar to PET but, if the two are mixed up in a
recycling bin, the whole collection becomes impossible to
recycle.
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44.  Numerous synthetic biodegradable polymers are available
and still being developed for sustained and targeted drug
delivery applications.
 Biodegradable polymers have proven their potential for the
development of new, advanced and efficient DDS and
capable of delivering a wide range of bioactive materials.
 However, only few have entered the market since many
drugs faces the problem of sensitivity to heat, shear forces
and interaction between polymers.
 These problems can be overcome by fully understanding
the degradation mechanism to adjust the release profile.
Conclusion
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45. REFERENCES
 Biotechnology/ U.Sathyanarayana.
 A text book of biotechnology/R.C.Dubey &
Maheshwari.
 Biodegradable polymers.ppt
 Bioplastic.1.ppt
 Recent Developments in Biopolymers/Vicki Flaris,
Gurpreet Singh(2009).
 Biopolymers in Medical Applications: Senthil S.
Kumar.
 www.bioplastics24.com
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