Article

TESTING THE BIODEGRADABILITY AND BIODEGRADATION RATES OF DEGRADABLE/BIODEGRADABLE PLASTICS WITHIN SIMULATED ENVIRONMENT

Authors:
  • Mendel University in Brno / Warsaw University of Life Sciences - SGGW
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Abstract

The objective of this study was to evaluate and compare the biodegradability and biodegradation rates of ‘single-use' plastic bags available on the market and labeled as degradable/biodegradable. The test was carried out under both aerobic and anaerobic conditions. The project length was 20 months. The biodegradation results in the laboratory conditions demonstrate that none of the degradable/ biodegradable bags showed visual changes and/or were broken into pieces and none of them experienced any disintegration or degradation. The cellulose filter paper (CFP) completely degraded after 10 days in the aerobic conditions and after 5 month in the anaerobic conditions, implying that the conditions required for biodegradation to occur in a sampling environment were present.

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... The biodegradability of various bioplastics under simulated landfill conditions was investigated by many scientists earlier [101][102][103][104]. By employing anaerobic digested sludge, they found that natural aliphatic polyester such as poly(3hydroxybutyrate-co-3-hydroxyvalerate) (PHB/HV; 92/8, w/w) degraded within 20 days of cultivation, while synthetic aliphatic polyesters such as poly-lactic acid, poly(butylene succinate) and poly(butylene succinate-co-ethylene succinate) did not degrade at all in 100 days [105]. ...
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  • S Bonhomme
  • A Cuer
  • A-M Delort
  • J Lemaire
  • M Sancelme
  • G Scott
Bonhomme, S., Cuer, A., Delort, A-M., Lemaire, J., Sancelme, M., Scott, G. Environmental Biodegradation of polyethylene. Polymer Degradation and Stability 81, 2003, s. 441 – 452.
  • I Vroman
  • L Tighzert
Vroman, I., Tighzert, L. Review Biodegradable Polymers. Materials 2, 2009, s. 307-344. Mgr. Ing. Magdalena Vaverková, Ph.D. magda.vaverkova@uake.cz doc. RNDr.Jana Kotovicová, Ph.D. kotovicj@node.mendelu.cz Ing. Dana Adamcová