The effect of Thai compost on biodegradability of polylactic acid based on ISO 14855-2 method

摘要

The plastic requirements of earth inhabitant are enormous and have environment impacts of such consumption. An average person consumes many tons of those materials which ultimately disposed as wastes. Therefore, the trend of environmental awareness increases the demanding of biodegradable plastic. Presently, the biodegradability test has been reported in various kinds of standards. However, the biodegradation in aerobic condition under controlled composting system is the main focus of this research. As we have known that microorganisms in compost are the key player of biodegradation which differ from country to country. Therefore, our own compost was fermented from rice straw together with cow dropping and urea for 60 days. It was found that the properties of compost were acceptable the requirements of ISO 14855-2. Such that the compost was utilized for testing the biodegradation of cellulose and polylactic acid powder which operated by Microbial Oxidative Degradation Analyzer (MODA). The compost was designed to control the humidity, aeration ratio and temperature at 58°C. It was discovered that the percentage of biodegradability of cellulose and polylactic acid powder were 80 and 98, respectively after 60 days testing. Thus, from this report, we have confirmed that our compost attain the criterion of standard requirement.