Biodegradable water-soluble polymers test methods

TEST METHODS FOR BIODEGRADABLE WATER-SOLUBLE POLYMERS... 

Test Methods for Biodegradable Water-Soluble Polymers... 

There have been numerous communications on the subject of biodegradation test methods, including aerobic compost (30), anaerobic bioreactor (31), general methodology and future directions (32—34), and a fine review article (24). ASTM (22) and MITI (35) have also set forth standard testing protocols for plastics, as shown in Table 2, whereas OECD test methods (29) are more suited to water-soluble polymers. 

Waste-management requirements and disposal options are the drivers for research to develop environmentally biodegradable polymers and to establish laboratory testing protocols. It is commercial opportunities that indicate polymer types, structures, properties and uses that dictate waste management and disposal requirements. Disposal methods and locations identify the testing protocols that must be established for polymers in order to evaluate their environmental degradation under laboratory simulated environmental exposure conditions. Major options for the disposal and waste-management of water-soluble polymers are indicated in Fig.2. 

Gas evolution tests are popular test methods because they are relatively simple, rapid (days to weeks) and sensitive. A direct measure for mineralisation is determined, and water-soluble or insoluble polymers can be tested as films, powders or objects. Furthermore, the test conditions and inoculum can be adjusted to fit the application or environment in which biodegradation should take place. Aquatic synthetic media are usually used, but also natural sea water or soil samples can be applied as biodegradation environments. A prerequisite for these media is that the backgroimd COa-evolution is limited, which excludes the application of real composting conditions. Biodegradation under composting conditions is therefore measured using an inoculum derived from matured compost with low respiration activity . ... 

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