UND IRES Research Project
Biodegradability of Polyurethane Foams with Adjustable Rate of Biodegradation.
Biodegradability of Polyurethanes
Pollution by plastics is one of the most important threats to the environment. Thus the project will evaluate biodegradability of specifically designed polyurethane foams with adjustable rate of biodegradation to obtain eco-friendly polyurethane foams with advanced technological properties at the same time.
A variety of eco-friendly polyurethane foams with defined and adjustable rates of biodegradation will be obtained to enable large scale industrial decontamination.
The designed polyurethane foams will be used in subsequent applied research with our industrial partners, e.g., Dekonta a.s., for both decontamination and biodegradable polymer production.
Microcellular plastics with different morphologies are widely studied and used. They are in high demand for various environmental applications, e.g., sorption materials, packing materials for biofilters, catalyst supports in biotechnology applications, etc.
Polyurethanes can be synthesized as tailor-made polyester-ether polyols with a different ratio of ether/ester segments to tune the polymer hydrophilic/lypophilic balance, thus optimizing both the adhesion of microorganisms and hydrolytic degradability. In the environment, these materials can be used as either the main or supplementary source of carbon, energy and nitrogen; the latter may be of importance in the case of removal of poorly degradable pollutants via co-metabolism.
Advanced polyurethanes with adjustable rate of biodegradation are designed on both molecular and supramolecular structural levels, to use them as supports for accumulation and growth of degrading microorganisms. The surface structure, specific surface area, surface hydrophobicity, foam morphology (closed vs. open cells) are the essential parameters defining the material from the point of biofilm development.
To evaluate comprehensively both ways of using such materials, as an eco-friendly biofilm development support (with an easy ecological disposal after use) and as a source of carbon, energy and nitrogen, a suite of many analytical methods should be used.
Namely, the evaluation of quality and quantity of high-molecular and low-molecular weight metabolites release, changes of polyurethane structure on both molecular and supramolecular structural levels, ecotoxicological evaluation, surface properties, and kinetics of biofilm development must be conducted to evaluate the potential application of these polymers.
The project is conducted in collaboration by the Institute of Chemical Technology, Prague and Institute of Macromolecular Chemistry of the AS CR, v.v.i., Prague, which designs advanced microporous polyurethane foams with adjustable rate of biodegradation. Biodegradation tests include the analytical evaluation of four basic processes: biodeterioration, biofragmentation, assimilation and surface colonization.
Biodeterioration will be monitored using spectroscopic methods, e.g., FTIR and Raman spectroscopy and surface morphology evaluation using SEM. Biofragmentation will involve the identification of oligomers using MALDI-TOF and low-molecular weight products by HPLC-UV/RI, HPLC-MS and/or GC-MS.
Assimilation will be evaluated by monitoring the development of microbial biomass via oxygen consumption using Oxitop. Surface colonization will be predicted by applying thermodynamic and XDLVO models to the obtained data on zeta potential and contact angle measurements. Initial cell attachment and surface colonization will be analyzed by microscopic observations followed by image analysis using NIS Elements software.
Those methods allow us to study changes of polyurethanes on both molecular and supramolecular structural levels, release of intermediates and material suitability as a biofilm carrier.