Biologisk nedbrytning experimenten av polymerik material: ävervakning och analys

Plastic debris has become a global crisis due to littering and misplaced waste management. The use of biodegradable materials can ease the problem, but it is not always the answer. Products made of biodegradable materials are still to be waste managed since biodegradation can be long process and is highly dependent on the environment conditions. Hence, the use of biodegradable materials is justified only when retrieving the product after use is impossible or prohibitively expensive or separating it from organic matter is impossible. This study was made to investigate biodegradable materials that are to be used in device that is operating in broad range of operational conditions and cannot be retrieved back after use in most cases. In the literature part of this study the biodegradation is defined along with properties and conditions that affect the biodegradation process. Biodegradation of polyesters and cellulose, and standards used in the biodegradation experiments were reviewed. Biodegradation standards are studied in order to have clearer picture of the pursued degree of biodegradation and standardized properties in the biodegradation experiments. Review of different biodegradation tests and analysis methods is included as well to ensure that the experiments performed in this work are valid and comparable with other biodegradation studies. In this study, the biodegradation experiment was conducted in freshwater and home compost environments. The aim was to determine if the materials were able to be biodegradable in wide range of environments, less harmful as the conventional materials used in the industry and to estimate the rate of biodegradation. The duration of the experiments were 140 days with 10 different materials: A – J. The materials were analyzed throughout the duration 8 times except materials I and J which were analyzed after 140 days. The samples were analyzed mechanically, structurally, and thermally using tensile test, FTIR and DSC measurements, respectively. Also, weight ratio was analyzed. The degradation was visually observed from the surfaces of the samples and from mechanical testing in both experiment environments. Home compost environment showed clear signs of biodegradation where reinforcement fibers became visible and changed the color of some of the samples. Also, home compost samples had microorganisms growing on them, and biomass was developing around them. To conclude, material B, C and G had the most promising results with clear signs of biodegradation and had faster estimated biodegradation rate than the other studied materials. Material D had signs of biodegradation on the surface as well. However, the biodegradation rate was estimated to be much slower. In conclusion, it is recommended to use the studied materials A, B, D and G instead of the conventional non-biodegradable polymers. These materials will significantly lower the negative impact and long-term risks to the environment.