Test procedure - when we started...
With biologically degradable plastics the decomposition through naturally occurring micro-organisms such as bacteria, mushrooms and algae is caused. Biological degradableness is the suitability of a material for micro-organisms as a source for carbon to be used, which can be converted in carbon dioxide, biomass and water.
A EcoPure™ treated shoe sole (1% EcoPure™ portion) and a EcoPure™ treated shoe (5% EcoPure™ portion) as well as an untreated shoe stored in an anaerobic container atmosphere. The conditions in the container are similar to the conditions on a dump. The container is located below a large discharge pipe. From this pipe waste water is continuously discharged at a constant temperature. The samples are covered with waste materials and dipped completely into the anaerobic liquid. The cover of the container is prepared with holes which makes an active flow possible and offers one bacteria source for the samples. Through the constant liquid flow in the test container, thus the presence of microbes, the biological decomposition kicks in. This test procedure is identical to the ASTM guideline, ASTM D5210-92 (2000) „Standard test Method of Determining the Anaerobic biodegradation of plastic material in the Presence of Municipal sewage Sludge“.
The samples were placed into the anaerobic environment on 19 December 2006 . They were dipped for 24 hours daily, 7 days a week and altogether 253 days into the bacterial liquid. The testing time ended on 29 August 2007.
The supplied bacterial liquid remained constant with 32,6°C and with a flow of 0,36m/sec.
Test Biological Decomposition
At the completion of in each case 4 months, 6 months and 8 months testing period, the samples provided with EcoPure™ and the untreated samples were investigated concerning the biological decomposition. Beforehand they were cleaned with warm water, soap and an ultrasonic cleaning was completed.
SEM Photo Analysis
After the cleaning the samples, they were handed over to the Electron Microbe Lab in the Institute of Meteoritics, at the University of New Mexico. Professor Mike Spilde, the Director of the Institute, analysed the test and provided a detailed report to his findings.
Analysis with that Size Exclusion Chromatography Technik (SEC):
With this technique, the samples were set into a liquid condition (98% tetrahydrofuran - THF - and 2% triethyl) before the analysis and filtered. In the untreated sample a high point shows up in the Chromatogram after 4.5 minutes, in the 5% EcoPure™ sample this is not available and in the 1% EcoPure™ sample, it is considerably reduced.
The missing peak value in the molecular weight is an indicator for biological decomposition. A further indicator is the rise in the range of the maximum point for a low molecular weight for a period of 9.4 minutes. In summary, it is clear that the tested samples went through biological decomposition in an order of magnitude of 4%.
With the naked eye there is no signifant change can be determined between the EcoPure™ sample and the untreated sample. Through contact however it can be stated that the EcoPure™ sample is more flexible, substantially more flexible compared to the untreated sample. This is to be due to the chemical composition of the EcoPure™ sample in comparison to the untreated sample.
Based on the FTIR/ATR, DSC and SEC analyses, it becomes clear that the sample shows a 4% biological decomposition. Finally the report of the independent institute confirms this result.
Further tests using the ASTM D5511 (biodegradable test)
After this first positive results we made several further tests with the Fresenius Institute and several other 3rd party laboratories.