International Fachagentur Nachwachsende Rohstoffe e. V.

 

Bioplastics

Bio-plastics are made of renewable raw materials and replace the previously used plastics made from fossil raw materials. Scientists and technologists don’t only adjust them to conventional production machinery, but develop new applications for them. Therefore packaging, disposable tableware, or mulch from bioplastics are already available.

Depending on the requirement, some bioplastics are guaranteed a long life, while others are easily biologically degradable and disintegrate naturally into non-toxic raw materials. Whether bioplastics are put to use in biogas plants after their material use, thermally recycled or composted: the portion of the plant-based materials (many plastics are compounds from fossil and vegetable components) only releases the CO2, which was bound by the plants during their growth phase. In order to calculate the proper CO2 balance however, the carbon dioxide which was released during the production process of the bioplastics, needs to be taken into account.   

Bioplastics can be produced from many biogenic raw materials. The starch occupies a pivotal role. Likewise cellulose and sugar currently gain increasingly importance.

Starch is widely available, inexpensive and for the development and production of bioplastics the most interesting raw material. A high proportion of the produced starch is directly transformed in continuous biotechnological processes into glucose. Therefrom thermoplastic polyesters and polyurethanes are made in biotechnological and / or chemical process. As particularly inexpensive raw materials the products of the milling industry flour and semolina play a role in certain applications as well as pellets or powder made from grain, potatoes or corn. By-products of the starch industry can also be used as raw materials for fermentation processes.

Cellulose is contained in most plants in large quantities and in addition to the wood it is quantitatively the most important renewable resource. Worldwide, about 1.3 billion tons per year will be "harvested" for technical applications. Even though the end product wood pulp mainly used for the manufacture of paper and paperboard, also provides potentials for the plastics production.
Cellulose esters, for example, are often used as polymer components for compounding with other biopolymers. Also the clear-sighted cellophane foil for packagings is a cellulose product.

Sugar (sucrose) from beet or cane is a disaccharide and the starch as a raw material in many aspects equal. Since sugar is technically variously applicable, the use as a renewable resource offers interesting perspectives.

Numerous other natural resources such as

  • Casein, a protein from skim milk,
  • Chitin and chitosan from crab shells,
  • Gelatin, a collagen protein from animal bone or skin,
  • Vegetable oils and
  • Proteins from cereals (wheat or corn)

can be used for the development and production of bioplastics. Epoxy resins from linseed oil, for example, are already qualitatively equal to the synthetic epoxides.

 

If you would like to know more about bioplastics, please follow this link to the automatically translated pages.

 

biowerkstoffe.fnr.de

(Source: © Creatix / Fotolia)