Biopolymer - an environmentally friendly and harmless polymeric material continues to show good growth potential. A recent survey conducted shows that global demand would grow from 180 million tons to 258 million tons by 2010 - definitely growing faster than the commonly used plastics such as polyolefins. Toyota expects that the demand would reach almost 5% of the total petrochemical based polymer demand in the World by 2020. Several factors such as soaring oil prices, worldwide interest in renewable resources, growing concern regarding greenhouse gas emissions and a new emphasis on waste management have created renewed interest in biopolymers and the efficiency with which they can be produced.
New technologies in plant breeding and processing are narrowing the biopolymers-synthetic plastics cost differential, as well as improving material properties. (for example: Biomer is developing PHB grades with higher melt strength for blown film). Mounting environmental concerns and legislative incentives, particularly in the EU, have stimulated interest in biodegradable plastics. Implementation of the Kyoto Protocol will also bring into sharper focus the relative performance of biopolymers and synthetics in terms of their respective energy use and CO 2 emissions. (Under the Kyoto Protocol, the European Community agreed to reduce emissions from 1990 levels by 8% during the period 2008 to 2012 and Japan has similarly agreed to reduce emissions by 6%). As a rule of thumb, starch-based plastics can save between 0.8 and 3.2 tons of CO2 per ton compared to one ton of fossil fuel-derived plastic, the range reflecting the share of petroleum based copolymers used in plastics.

There are three major degradable polymer groups in the market :
PHA or PHB
Polylactides (PLA)
Starch-based polymers
Other materials used commercially for degradable plastics are lignin, cellulose, polyvinyl alcohol, and poly-e-caprolactone. There are many producers who are manufacturing blends of degradable materials either to improve the properties of these materials or to reduce product costs.

PHB and its copolymers have been mixed with a variety of polymers, having very different characteristics; biodegradable and non-biodegradable, amorphous or crystalline with both different melting points and Tg in order to improve their processability and low impact resistance. Blends are also being used to improve PLA properties. While normal PLAs behave much like a polystyrene - exhibiting brittleness and low elongation to break, the addition of 10-15% Eastar Bio- a petroleum based biodegradable polyester- measurably improves ductility, with corresponding higher flexural modulus and impact strength as an example. To increase biodegradability, while simultaneously lowering the cost and preserving resources, it is possible to blend polymeric materials with natural products such as starches. Starch is a semi crystalline polymer composed of amylase and amylopectin with the ratios varying depending upon the plant source. As starch is hydrophilic, the use of compatibilizers can play a critical role in successfully blending this material with otherwise incompatible hydrophobic polymers.

Biopolymers have a huge limitation of higher pricing compared to conventional polymers. While the conventional commonly used polymers cost around US$1000-1500/MT, biopolymers cost from about US$4000/MT to as high as US$15,000/MT for material such as polyhydroxybutyrates. However, more commonly used biopolymer like polylactic based polymer cost at least US$4000/MT. As the initial phase of development gets over and manufacturing plants attain higher productivity, prices are projected to decline significantly. However, it will never really reach the level of commonly used petroleum based polymers. Currently, from an overall price comparison standpoint, biopolymers are 2.5-7.5 times more expensive than traditional major petroleum based plastics. Yet, only five years ago, biopolymers were 35-100 times more expensive than existing non-renewable, fossil fuel based equivalents.

From a Life Cycle perspective, biodegradable polymers offer the potential for gains by enabling the diversion of waste from landfills, where some 80% of plastic waste now end up, to a fully recoverable resource in the form of either energy or compost products that can be further recycled through soil and plants, thereby closing out the carbon cycle. European research indicates starch based polymers offer energy and emission savings of 12-40 GJ/ton of plastic, and 0.8-3.2 tons of CO2 emissions/ton of plastic compared to one ton of fossil derived polyethylene. For oil seed based plastic alternatives, green house gases emissions savings in CO2 equivalents has been estimated to be 1.5 ton per ton of polyol made from rapeseed oil. The National Institute of Standards (NIST) recently completed work on life cycle inventories for two new soy polyols (one of the main components in the polyurethane polymer backbone). Soy based polyols had only one-fourth the level of environmental impacts that petroleum based polyols show. There were significant reductions in global warming, smog formation, ecological toxicity and fossil fuel reduction.

There are a large number of companies, particularly in Western Europe, USA, Japan and China either engaged in active manufacture or positioning them to manufacture degradable plastics. Many of these firms are operating with plants of less than 6,000 tpa, and succeeding through product differentiation and good marketing. Globally, of the 80 organizations producing degradable plastics or their blends, about 8% of the companies are commercially producing PHA based plastics, and approximately 20% of the companies listed are producing PLA related plastic materials. More than 30% are producing either starch based biodegradable plastics or blends containing starch as an important component. As of 2002, there were 47 producers of biopolymers in the world, only 2 of which had capacity greater than 40,000 tpa and 6 had capacity greater than 10,000 tpa. One single NatureWorks plant at 140,000 tpa, accounted for an estimated 40% of world capacity in 2002.
Metabolix, Mitsubishi Inc, Kaneka and Biomer are significant names in the high tech PHA/PHB category of biodegradable plastics.
Procter & Gamble and Kaneka have announced a joint development agreement for the completion of R&D leading to the commercialization of NODAX H, chemically known as PHBH or poly (3-hydroyxbutyrate-co-3-hydroxyhexanoate).
Shimadzu Corp. (Japan), Mitsui Chemicals (Japan), P.T. Toyota Bio Indonesia is also producing PLA (Toyota Eco Plastic) which is used for automotive applications.

Amongst starch-based plastics produced, Mater-Bi, (manufactured primarily from corn or potato starch), available from Novamont (Italy), is the dominant global supplier and is also the largest seller. Mater-Bi is suitable for manufacturing injection moulded pieces, films (for bags) and a starched based loose fill packaging material. Rodenburg Biopolymers, Netherlands, produces 'Solanyl' (made from potato waste). Solanyl is principally marketed for 'Grow and Go' nursery pots and other horticultural applications. Biotec (Germany) produces Bioplast suitable for injection molding as well as sheet film extrusion and blown film. National Starch and Chemical Co. Licenses/produces Ecofoam, and Avebe (Netherlands) a potato based starch manufacturing company produces Paragon.

The use of legislative instruments is a significant driver influencing the adoption of biopolymers in place of the petroleum based polymers. In Europe and Japan, the automotive and packaging sectors are most affected by ratified legislation. The Packaging and Packaging Waste Directive 94/62/EC and the End of Life Vehicle Directive 2000/53/EC are two examples of such legislative drivers. Additionally, in the U.S. Section 9002 of the Farm Security and Rural Investment Act of 2002 confers federal purchasing preference to biopolymer based products.

Ultimately while oil prices, depleting oil reserves, total life cycle, impact on sustainable resources and the use of legislative instruments are major driving forces for the use of biopolymers. However, factors that will decide actual use of biodegradable polymers will include suitability of material properties for converters; technical feasibility of processing options and commercial viability of production and processing.