Biodegradation Of Polymeric Materials Research Articles

REVIEW OF EVALUATION METHODS FOR BIODEGRADABILITY OF POLYMERIC MATERIALS

Development and further use of biodegradable polymeric materials requires prior assessment the degree of their biodegradation. There are a large number of methods developed taking into account the specifics of the destruction of polymeric materials. The purpose of this review is to systematize scientific and technical information regarding methods for assessing the biodegradation of polymeric materials. Laboratory methods of researches, including the following: influence of abiotic factors (temperature, moisture, UV irradiation), impact of microorganisms (fungi, bacteria, yeast), respiratory methods (Sturm, Zahn-Wellness, etc.), conditions of composting, enzyme analysis methods, ecotoxicity tests are given. Test methods in both aqueous and solid media are also presented. The parameters of biodegradability, which determine the degree of destruction (mass, strain strength, molecular weight distribution, temperature characteristics, macro-and microstructure of samples, etc.) or the composition and properties of the biological system in which biodegradation takes place (acidity, respiratory activity, chemical and microbiological composition of soil or other biological environment, etc.) are considered as well. Advantages of laboratory methods for studying the biodegradation of polymeric materials could be realized in the given directions: varying of the experimental conditions (temperature, humidity, UV and IR radiation, the presence of aggressive media, etc.), biochemical compositions of the environment; study of the ability of individual strains of microorganisms to dispose of polymer composites and targeted selection of the most active microbial associations (in particular, for the manufacture of special biocomposts); utilize of simple and fast methodical approaches and modern devices for evaluation experiments. However, laboratory methods do not always allow modeling a set of endogenous and exogenous factors that define the process of biodegradation in the natural environment. Therefore, this review also considers methods for assessing biodegradation in the environment. So, the essence of the test regarding the samples’ burial in the ground is given. International standards governing methods for assessing the biodegradability of organic substances and polymeric materials are summarized. Applying different test methods, one can evaluate the whole process of biodegradation of polymeric materials, consisting of several stages, which occur regardless the type of microorganisms and accompanying abiotic factors, and can be represented as follows: adhesion → colonization → biodeterioration → biofragmentation → assimilation → mineralization. Thus, the adhesion and colonization of microorganisms can be estimated by visual, bioindicator and spectral methods. Abiotic degradation and biodeterioration are associated with physical tests (e.g., thermal and physico-mechanical). Biofragmentation is detected by identifying fragments of lower molecular weight (i.e. by chromatographic methods). In turn, assimilation is assessed by the amount of metabolites produced using, for example, respirometric methods or involving analysis of microbial biomass (e.g., macroscopic and microscopic observations). The most productive should be considered a comprehensive approach to the study of biodegradation of polymers. To determine the reliable kinetic parameters and link the mechanism of this process, it is necessary to carry out a comparative analysis of the results of physical, chemical, microbiological experiments, which are carried out in both laboratory and natural conditions.

Polyvinyl Chloride Biodegradable Composite Materials, the Analysis of Biodegradability Research Methods

This article presents a scientific review of the literature on biodegradable polymer composite materials based on polyvinyl chloride. We summarized data on the effect of modifiers of natural and synthetic origin on the biodegradability of polyvinyl chloride material. The main methods for studying the biodegradability of polymeric materials are considered.

Using the method of pyrolytic mass spectrometry in the study of biodegradable polymeric materials

The results of pyrolytic mass spectrometry studies of biodegradable polymeric materials based on polyolefins and segmented polyurethanes with various functional additives are summarized. The structure and composition of initial and after exposure in soil, climate chamber and after exposure to microorganisms (bacteria, yeast) composites are characterized. In the research presented, influence of acetates and complexonates of metals, including cobalt, copper and zinc, on the structural changes in the high pressure polyethylene (HPPE) occurring under the impact of factors such as temperature, humidity and UV-radiation is investigated. It was established, that samples of HPPE, modified by cobalt acetate and cobalt and copper complexonates are responsive and most sensitive to the action of above-mentioned physical factors. Investigation of a segmented polyurethanes (SPU) of a different chemical structure influenced by a factors, modeling of the environmental conditions was conducted. It was shown using pyrolytic mass-spectrometry method and monitoring of samples’ weight loss that under the influence of above-mentioned environmental factors in the SPU occurs processes, resulting to changing its micro heterogeneous structure. It is established that SPU having ester links in its structure and being exposured in soil for 120 days is predominantly attacked by microorganisms, then the main active factor appears to be soil’ pH value – after 300 days in soil with alkaline or acid solution SPU sample decomposes into a separate fragments. Features of the chemical structure of urethane polymers synthesized on the base of hydroxylated rapeseed oil (polyol) were examined. Analysis of the results showed that the macromolecular compounds obtained are segmented polyurethanes which thermal degradation occurs in two stages: hard blocks are destroyed at the first stage, while polyol part (soft blocks) decomposes at the second stage, allowing to identify the temperature area of polymer destruction and thus its temperature region of operation. It is shown that the most suitable from the viewpoint of environmental friendly is polyurethane composition containing more than 50% of polyol. Thermal mass-spectrometry (TMS) has been employed to investigate processes of thermal destruction of segmented polyurethane and it’s compositions filled by polysaccharides: starch, dextrin, chitosan. The features of thermal destruction for segmented polyurethane and related compositions before and after their storage in a soil have been determined. Application TMS is shown to permit the processes of biodegradation of polymeric materials to investigate.

Biodegradation of Polymeric Materials. Generalized Kinetic Data

Information about generalized kinetic data which can describe biodegradation of polymeric materials (kinetics of biomass growth and methods of investigation of its formal mechanism of biodegradation, microorganism adhesion) is presented and discussed.

New Insight into Biodegradation of Polylactide (PLA)/Clay Nanocomposites Using Molecular Ecological Techniques

Novel molecular ecological techniques were used to study changes in microbial community structure and population during degradation of polylactide (PLA)/organically modified layered silicates (OMLS) nanocomposites. Cloned gene sequences belonging to members of the phyla Actinobacteria and Ascomycota comprized the most dominant groups of microorganisms during biodegradation of PLA/OMLS nanocomposites. Due to their numerical abundance, members of these microbial groups are likely to play an important role during biodegradation process. This paper presents new insights into the biodegradability of PLA/OMLS nanocomposites and highlights the importance of using novel molecular ecological techniques for in situ identification of new microorganisms involved in biodegradation of polymeric materials.

熱分解分析法および質量分析法による高分子材料の生分解性評価

熱分解分析法および質量分析法による高分子材料の生分解性評価

Aerobic Biodegradation of Synthetic and Natural Polymeric Materials: A Component of Integrated Solid-Waste Management

Abstract Solid waste collection, handling, and processing systems are changing worldwide as concerns increase regarding the environmental impact of solid waste. Recycling, waste to energy, and composting options are all expected to increase significantly as available landfill capacity decreases. As composting becomes an important method of managing solid waste, information about the biodegradability of polymeric materials and products is required in order to understand the fate of polymers in the environment. This paper describes the development of a tiered testing strategy for assessing the aerobic biodegradability and compostability of synthetic polymers. This testing strategy is demonstrated with polycaprolactone (PCL), a polymeric material that is generally regarded as biodegradable and compostable. PCL biodegradation was assessed in screening-level tests using the OECD 301B and ASTM D5338 test methods. In addition, 14C-PCL was synthesized and used in confirmatory-level biodegradation tests that were ...

Use of Biosynthetic, Biodegradable Thermoplastics and Elastomers from Renewable Resources: The Pros and Cons

Abstract For several reasons, biodegradable polymers have recently attracted much public and industrial interest. This contribution focuses on microbial aspects of the biodegradability of polymeric materials in the environment. It provides an overview on biodegradability and the mechanisms of degradation of relevant natural and technical polymers. Almost all biosynthetic polymers, which are readily available from renewable resources, are biodegradable within a reasonable time scale. Many semibiosynthetic and even chemosynthetic polymers are also biodegradable if they contain chemical bonds which also occur in natural compounds. Only a few polymers are truly persistent. Arguments for and against the use of such polymers are summarized.