1. Green Polymers for Sustainable Development Dr
Green Polymers for Sustainable Development   Dr. Bhavesh Patel Principal V.P. and R.P.T.P. Science College, Vallabh Vidyanagar -

2. Plastic – A necessary evil
General
-Plastic is a material made up of one or more polymer.
-Main source of material needed to manufacture plastics are fossil fuels (petrochemicals).
-Take very long time to biodegrade when disposed.
Concerns
-Rising cost of fossil fuel.
-Environmental impact.

3. What are Bioplastics?
Bioplastics or organic plastics are a form of plastics derived from renewable biomass sources, such as vegetable oil, corn starch, pea starch or microbiota, rather than fossil-fuel plastics which are derived from petroleum.
Bioplastics are designed to biodegrade.
If something made of bioplastic is buried in the ground, microorganisms will break it down into carbon dioxide and water.
Bags made of bioplastic can be thrown away and buried with other biodegradable garbage

4. Why Bioplastic? Depletion of fossil recourses
When plastics made from petroleum are burned, they release the carbon dioxide contained in the petroleum into the atmosphere, leading to global warming.
Bioplastics are environmentally friendly because, compared with traditional plastics, their production results in the emission of less carbon dioxide, which is thought to cause global warming.
They are also biodegradable, meaning that the material returns to its natural state when buried in the ground.
The use of bioplastics offers significant advantages not only in an ecological sense but also in an economical sense.

5. Advantages
The production and use of bioplastics is generally regarded as a more sustainable activity when compared with plastic production from petroleum (petroplastic), because it relies less on fossil fuel as a carbon source and also introduces fewer, net-new greenhouse emissions if it biodegrades.
They significantly reduce hazardous waste caused by oil-derived plastics, which remain solid for hundreds of years, and open a new era in packing technology and industry 

6. Biopolymers and Bioplastics
Polymers synthesized by biological system are Biopolymers.
Plastics manufactured by using biopolymers are Bioplastics.
Concept of bioplastic is not new, Henry Ford developed a method of manufacturing plastic car parts from soybean in mid of 1990s.
Today bioplastics are gaining popularity once again as newer techniques developed through biotechnology.

7. Bioplastic Types Biopolymers from living organisms
-Cellulose, Soy protein, Starch, Polyesters
Polymerizable molecules
-Lactic acid, Triglycerides

8. Bioplastic types 1. Starch based plastics
Constitutes about 50 percent of the bioplastics market
Thermoplastic starch, such as Plastarch Material, currently represents the most important and widely used bioplastic.
Possesses the characteristic of being able to absorb humidity, and is thus being used for the production of drug capsules in the pharmaceutical sector.
Flexibiliser and plasticiser such as sorbitol and glycerine are added so the starch can also be processed thermo-plastically.

9. Bioplastic types 2. Cellulose based plastics
Cellulose bioplastics are mainly the cellulose esters and their derivatives
E.g. cellulose acetate, nitrocellulose, celluloid.

10. Bioplastic types 3. Polylactic acid (PLA) plastics
Polylactic acid (PLA) is a transparent plastic produced from cane sugar or glucose.
It not only resembles conventional petrochemical mass plastics in its characteristics, but it can also be processed easily on standard equipment that already exists for the production of conventional plastics.
PLA and PLA blends generally come in the form of granulates with various properties, and are used in the plastic processing industry for the production of foil, tins, cups and bottles cont...

11. Bioplastic types 3. Polylactic acid (PLA) plastics
Enzymes are used to break starch in the plants down into glucose, which is fermented and made into lactic acid.
This lactic acid is polymerized and converted into a plastic called polylactic acid, which can be used in the manufacture of products after being heated and shaped.

12. Bioplastic types 4. Bio-derived polyethylene
The monomer of polyethylene is ethylene.
Can be produced by fermentation of agricultural feedstocks such as sugar cane or corn.
Bio-derived polyethylene is chemically and physically identical to traditional polyethylene - it does not biodegrade but can be recycled. It can also considerably reduce greenhouse gas emissions.

13. Bioplastic types 4. Genetically modified bioplastics
Genetic modification (GM) is also a challenge for the bioplastics industry.
None of the currently available bioplastics - which can be considered first generation products - require the use of GM crops.
Looking further ahead, some of the second generation bioplastics manufacturing technologies under development employ the "plant factory" model, using genetically modified crops or genetically modified bacteria to optimise efficiency.

14. Bioplastic types 5. Aliphatic polyesters
The aliphatic biopolyesters  polyhydroxyalkanoates (PHAs) are mainly produced in large quantity, characterized and used commercially.
These include- poly-3-hydroxybutyrate (PHB), polyhydroxyvalerate (PHV) and polyhydroxyhexanoate PHH.
PHB is the best known PHA accumulated by many organisms

15. PHA – Novel compound
Polyhydroxyalkanoates (PHA) is a biological polyesters accumulated by wide range of bacteria.
It is an intracellular carbon and energy storage compound.
Produced under limiting nutritional condition of N, P, S, Mg etc. and in presence of excess of carbon.
Many companies have started producing PHA using pure culture of Ralstonia eutropha.

16. Chemical Structure of PHA
PHAs can be divided in to three on the basis of chain length and monomer Small chain length (SCL), Medium chain length (MCL) Copolymer
e.g. PHB-co-HV
MCL (6-14 carbon) PHA have advantage over SCL i.e. low crystallinity and high elasticity.
Copolymer produced by many bacteria (SCL-MCL) have superior mechanical properties similar to Low Density Poly Ethylene (LDPE), depending on the monomer composition.

17. PHA - Properties
The material properties of of PHAs are similar to those of conventional plastics such as polypropylene
Properties of any PHAs depends on monomers, chain length and molecular weight.
About 120 monomer units with different R-group have been reported.
Biocompatibility, Biodegradable.

18. PHB – A Most Common PHA
Poly-3 Hydroxy Butyrate (PHB) is the most commonly found member of PHA family.
PHB is thermoplastic or elastomeric materials with melting point oC.
Properties of PHB is similar to the petroplastic polypropylene but its high melting point makes the processing difficult.
Cont…

19. PHB
Poly-3-hydroxybutyrate (PHB)
The biopolymer poly-3-hydroxybutyrate (PHB) is a polyester produced by certain bacteria processing glucose or starch. Its characteristics are similar to those of the petroplastic  polypropylene.
PHB is distinguished primarily by its physical characteristics. It produces transparent film at a melting point higher than 130 degrees Celsius, and is biodegradable without residue.
Copolymer of PHB are less stiff, tougher and has melting point about 100oC.

20. PHA - Producers
Among many microbes known to produce PHA only few are exploited commercially. These include-
Ralstonia eutropha (earlier A.eutrophus)
Alcaligenes latus
Pseudomonas oleovorens
Recombinant E.coli
Bacillus megaterium
Azotobacter vinelendii
Substrates: glucose, sucrose, n-alkanes, n-alcohols, organic acids.
Recombinant E.coli produces 101 g/l of cell dry wt. with 80% PHB within 39 hrs. of fermentation using glucose mineral medium cont…

21. PHA - Producers 1) Require limitation of nutrients for PHA synthesis
PHA produces can be divided into 2 groups-
1) Require limitation of nutrients for PHA synthesis
Produced by: Ralstonia eutropha (earlier A.eutrophus), Pseudomonas oleovorens
2) Do not require limitation of nutrients for PHA synthesis and can accumulate it during growth.
- Produced by: Recombinant E.coli. , mutant of A. vinelendii, Alcaligenes latus

22. Fermentation v/s Field
Fermentation is a powerful way to produce different biopolymer using bacteria.
Production of bacterial polyesters and lactic acid by fermentation is already started.
Using GE gene responsible for plastic production can be transferred to plants to create plastic.
Arabidopsis thaliana was created through GE.

23. PHA Production
High production cost of PHAs compared to petrobased polymers
Efforts to reduce the price of PHAs by developing better bacterial strains, more efficient fermentations and economic recovery procedures

24. Its not easy being green
Production cost
-Synthetic Plastic ~ 1 € / Kg
-Poly lactic acid ~ € / Kg
-Starch compound ~ € / Kg
-PHA ~ € / Kg
Little hope
Transgenic plants can produce large quantity of PHAs which lowers the cost of PHA to a level comparable to conventional plastic.

25. Lowering the production cost
Pure culture
- Expensive raw materials
- High investment and operational cost
- High yield of PHA up to 80% of cell dry wt.
Mixed culture (activated sludge)
- Cheap substrate
- Low operational cost
- Low yield of PHA up to 60% of cell dry wt.

26. Production strategies
Step 1
Two acetyl CoA are condensed to form aceto acetyl CoA by β ketothiolase
Step 2
Acetoacetyl coA is reduced to 3-hydroxy butyryl CoA by NADPH linked reductase
Step 3
PHA synthase finally links 3-hydroxy butyryl CoA to the growing chain of PHB.

27. Sustainable development & PHA
PHA is the main components in creating sustainable plastic industry.
PHA reduces our dependency on non renewable fossil fuels.
Easily Biodegradable.

28. Uses of Bioplastic
Bioplastics are already being used in automobile interiors and in cases for consumer electronics.
Toyota Motor Corp. uses bioplastics in the manufacture of auto parts, employing them in the cover for the spare tire
Mitsubishi Plastics has already succeeded in raising the heat-resistance and strength of polylactic acid by combining it with other biodegradable plastics. The result was used to make the plastic casing of a new version of Sony Corp.'s Walkman.
There are a growing number of other uses for the materials as well, including artificial fibers, medical products & construction materials.

29. Applications Packaging
The use of bioplastics for shopping bags is already very common.
After their initial use they can be reused as bags for organic waste and then be composted.
Trays and containers for fruit, vegetables, eggs and meat, bottles for soft drinks and dairy products and blister foils for fruit and vegetables are also already widely manufactured from bioplastics.

30. Applications Catering products
Catering products belong to the group of perishable plastics.
Disposable crockery and cutlery, as well as pots and bowls, pack foils for hamburgers and straws are being dumped after a single use, together with food-leftovers, forming huge amounts of waste, particularly at big events.

31. Applications Gardening
Within the agricultural economy and the gardening sector mulch foils made of biodegradable material and flower pots made of decomposable bioplastics are predominantly used due to their adjustable lifespan and the fact that these materials do not leave residues in the soil.
This helps reduce work and time (and thus cost) as these products can simply be left to decompose, after which they are ploughed in to the soil.
Plant pots used for flowering and vegetable plants can be composted along with gardening and kitchen litter.

32. Applications Medical Products
In comparison to packaging, catering or gardening sectors, the medical sector sets out completely different requirements with regards to products made of renewable and reabsorbing plastics.
The highest possible qualitative standards have to be met and guaranteed, resulting in an extremely high costs, which sometimes exceed Euro per kilo.
The potential applications of biodegradable or reabsorbing bioplastics are manifold.

33. Applications Sanitary Products
Due to their specific characteristics, bioplastics are used as a basis for the production of sanitary products.
Foils made of soft bioplastic are already used as diaper foil, bed underlay, for incontinence products, ladies sanitary products and as disposable gloves. 

34. In June 2005, a US company (Metabolix) received US presidential green chemistry challenge award for their development and commercialization of a cost effective method for manufacturing PHAs.

35. SUMMARY & CONCLUSIONS Recycling possible High market potential
Main benefits- carbon dioxide emmission reduction. Saving fossil resources
High consumer acceptance.

36. Thank You
Q & A