Biodegradable polymers in agricultural applications

S GUILBERT, ENSA.M, INRA, France, P FEUILLOLEY, CEMAGREF, France, H B E W A, ADEME, France and V BELEON-MAUREL, CEMAGREF, France 

Since the 1950s, the use of plastics for agriculture has been booming. Between 1990 and 1999, the worldwide consumption increased by 62% and by 185% since 1985, to reaeh a volume estimated at 2,850,000 tons (Jouet, 2003) in 2003. This consumption only represents 4% of the global plastic consumption. 

The above volume generates a similar but often higher quantity of wastes that are difficult to dispose of by fanners. They have to comply with several obligations  

In agriculture, mulching films, low tunnel films and accessories (clips, twines, etc.) are difficult to eliminate. It is possible to replace them by biodegradable materials that can be composted at the farm or left on site to be biodegraded in the soil. In these cases the farmer does not need to collect them, transport them or pay for elimination. In agriculture, as well as in other sectors, it is estimated that 15% of the plastic market is substitutable by biodegradable materials. 

Plastics to be composted or recycled (fields where reuse or fine recovery are difficult). 

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Poly(e-caprolactone) (10) has been used as a biodegradable polymer in agricultural applications and other aliphatic polyesters find applications in medicine, as biodegradable sutures. 

Fritz X, Sandhofer M., Stacker C., Braun R. Strategies for detecting ecotoxicological effects of biodegradable polymers in agricultural applications, Macwrao/. Symp. 197 (2003) 397. 

Biodegradable polymers in agricultural applications 507 Table 19.3 Soil temperatures under mulching in 2002... 

What are the uses of biodegradable polymers in agriculture and biomedical applications ... 

The extremely active academical and industrial research focused on the use of biodegradable polymers for agricultural applications has induced the introduction of several products to the market. These products based on biodegradable materials are supposed to be applied as mulching films, green houses sheets, laminates, and containers in agricultural practices and for application such as soil structurization and controlled release of chemicals such as fertilizers and herbicides. 

Fritz, J., Sandhofer, M., Stacher, C., and Braun, R., 2002, Strategies for Detecting Undesired Ecotoxicological Effects of Biodegradable Materials in Agricultural Application. 7 World Conf. on Biodegradable Polymers and Plastics, Tirrenia (Pisa, Italy), 4-8 June, pp. 59. 

Commercial polyolefins show no significant reduction in molar mass in typical ambient biometric tests over many months or even years. The resistance of hydrocarbon polymers to biodegradation during use is one of their major advantages in agricultural application over bio-based plastics. The useful life of photo-biodegradable polyolefins is controlled commercially by appropriate transition metal complexes in which the ligands are... 

Biodegradable polymers for industrial applications Table 19.1 Applications of bioplastics in agriculture (Guilbert, 1999)... 

Biodegradable polymers are likely to be increasingly important materials in the future, finding use in applications as diverse as medicine, agriculture, and pharmacy. For applications such as packaging, they remain expensive. However, with changing public attitudes towards enviromnental pollution, it is likely that objections based purely on cost will dimiiush, and that such applications will also grow in the years ahead. 

In the recent years, new markets have arisen for biodegradable polymers such as poly(butylene adipate-terephthalate), poly(lactide), poly(butylenesuccinate), or poly(3-hydroxybutyrate) and poly(carbonates). They constitute a new class of green polymers with wide application potential for packaging, clothing, carpets, applications in automotive engineering, foils, and utilities in agriculture. 

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