Development of biodegradable plastics from various kinds of biomass and elucidation for the safety of biodegraded intermediates from them

点击翻译按钮获取中文摘要

Ring opening graft copolymerization of ε -caprolactone onto cellulose diacetate in the presence of starch fillers was conducted by use of twin screw extruder through reactive processing. Obtained products were evaluated their physical and chemical characteristics. It was known from the results that the obtained composites reveal hydrophobicity, biodegradability and have practical physical properties.On the other hand, experimental results have been accumulated concerning the liquefaction of various biomass in the presence of phenols and polyols as well as concerning conversion of these liquefied products into phenol resins and urethane resins. Among them, polyurethane foams obtained from the liquefied products of bran were used as samples of in vitro biodegradable tests using isolated microorganisms obtained from the environment. After the 118 days of the biodegradation test, about 8% of weight loss was obtained in comparison with the control test, for example. SEM observation of the corresponding samples confirmed the occurrence of the biodegradation. IR spectra of the samples revealed the occurrence of the ether bondage scission, but did not give any change caused by the scission of urethane bondage. By the HPLC analysis of culture solution, the compositions different from the control results were obtained, which further confirmed the biodegradation of the samples. On the other hand, measurements of oxygen consumption in a closed system revealed the as high as 70% ofbiodegradability after 50 days of the testingperiod, showing high biodegradability.The total organic carbon amounts (TOC) after the biodegradation test was measured. The values obtained were found to be lower than those found for the control (the system having only activated sludge), which reveals that the possibility of remaining of the soluble biodegraded intermediates in the environment becomes to be negligible.