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Material

Biopolymers

Biopolymers are polymers that are generated from renewable natural sources, are often biodegradable, and not toxic to produce.

They can be produced by biological systems (i.e. micro-organisms, plants and animals), or chemically synthesized from biological starting materials (e.g. sugars, starch, natural fats or oils, etc.).

Biopolymers are an alternative to petroleum-based polymers (traditional plastics).
(Bio)polyesters have properties similar to traditional polyesters.
Starch-based polymers are often a blend of starch and other plastics (e.g PE), which allows for enhanced environmental properties.

Polyesters

Biopolymer type	Price (DKK/kg)	Density (kg/liter)
Aliphatic-aromatic copolymer	-	-
Aliphatic polyesters	-	-
CPLA	25-50	1.25
PCL	-	-
PHA	15-60	1.25
PLA	30-70	1.26

Starch-based polymers

Biopolymer type	Price (DKK/kg)	Density (kg/liter)
10 % Starch	-	-
50 % Starch	-	-
90 % Starch	20-40	-
Foamed starch	-	-

Others

Biopolymer type	Price (DKK/kg)	Density (kg/liter)
Casein formaldehyde	-	1.33
Celluose acetate	-	-
Horn	-	-

Environ- mentals notes Some polymers degrade in only a few weeks, while others take several months.
Biodegradability and other plastic properties strongly depend on the polymer structure. By changing the structure, these properties can be altered.

Price The above-mentioned prices are from December 1997.
The price of biopolymers is still fairly high compared to oil-based polymers. This is due to lower production-volumes than petroleum-based polymers.
However, the growing environmental consciousness and the application of life-cycle evaluations in the material circuit may help biomass-based raw materials to become mass-produced and cheaper, replacing traditional plastics in a number of applications.
Significant price reductions can be expected within the next two years.

References

Links:
Biodegradable Polymers and Plastics in Japan
Biofibre.net
Biopolymer.net
DTI, Centre for Product Development
GBF - Enviromental Biochemical Engineering
Proterra - Int. Centre for Agro-based Materials
How green are green plastics?

Companies:
Biotec GmbH
National Starch & Chemical

Books, Magazines & Papers:
Biopolymers (journal)
Biopolymers (paper)

Photo Thomas Nissen (Computer graphics)