Standards of biodegradation

Mineral microfillers have been tested in a plasticized starch matrix [CAR 01]. For example, micrometric particles of kaolin have been incorporated by extrusion. Due to a significant compatibility between the matrix and the filler, we note an increase in the glass transition temperature, a reduction in water absorption and an increase in the rigidity of the material. However, with the corresponding filler contents, these composites no longer satisfy the standards of biodegradation (at least 90% of the material has to be degraded). 

The noncompliance of these materials with international standards of biodegradability in different environments, the high concern for the increasing presence of plastic debris in the marine environment, even favoured by their tendency to fragment, and their potential negative impact on recyclability of traditional plastics, should prevent this technology from being considered as a preferred industrial option. 

The demand for consumer products that are truly biodegradable has led to national and international Definitions and Standards of Biodegradability. Regulatory bodies, such as ASTM (USA) and ISO (international), CEN (Europe), JAS (Japan), have all published such standards and issued logos that certify to meet these standards. Although the definitions, test methods, and certification requirements differ, the following are some common features ... 

Funabashi M., Ninomiya F., Kunioka M. Biodegradation of polycaprolactone powders proposed as reference test materials for international standard of biodegradation evaluation method, J. Polym. Environ. 15 (2007) 7. 

Kunioka M., Ninomiya E, Eurrabashi M. Biodegradation of poly(lactic acid) powders proposed as the reference test materials for the intematiorral standard of biodegradation evaluation methods, Polym. Deg. Stab. 91 (2006) 1919. 

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. 

Membrane manufacturers require a standard test to maintain batch-to-batch quality. Few use proteins. Materials selected are ones for which the complications are minimized, the probe is simple, fast, and cheap to detecl , does not readily biodegrade, and gives results, whatever they are, which are reproducible. There is no standardization of these tests within the industry. 

Biological. Bridid et al. (1979) reported BOD and COD values of 0.02 and 2.49 g/g using filtered effluent from a biological sanitary waste treatment plant. These values were determined using a standard dilution method at 20 °C for a period of 5 d. The ThOD for tert-butyl alcohol is 2.59 g/g. In activated sludge inoculum, 98.5% COD removal was achieved. The average rate of biodegradation was 30.0 mg COD/g-h (Pitter, 1976). 

Examples, which back np this theory, are the success of the Okotex 100 standard, the relative failine of the GISCODE system for paint-strippers and also the very limited snccess of biodegradable monld release agents in the construction in-dnstiy. 

Table 3 Logos of biodegradable polymers according to the standards [7]...

Figure 10 shows the biodegradation of Bionolle according to the standard test ISO 14855. All grades of Bionolle satisfy the criteria of biodegradation. 

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