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

采用双螺杆挤出反应工艺，在淀粉填料的存在下，进行了ε -己内酯与双乙酸纤维素开环接枝共聚反应。对所得产品的理化特性进行了评价。结果表明，所制备的复合材料具有疏水性、可生物降解性和实用的物理性能。另一方面，关于各种生物质在苯酚和多元醇存在下的液化以及这些液化产物转化为苯酚树脂和聚氨酯树脂的实验结果已经积累起来。其中，从麸皮液化产物中获得的聚氨酯泡沫作为样品，使用从环境中获得的分离微生物进行体外生物降解试验。例如，经过118天的生物降解试验，与对照试验相比，体重减轻了约8%。对相应样品的SEM观察证实了生物降解的发生。样品的红外光谱显示了醚束缚的发生，但没有显示氨基甲酸乙酯束缚的断裂引起的任何变化。通过HPLC对培养液进行分析，得到了不同于对照结果的成分，进一步证实了样品的生物降解性。另一方面，封闭系统的耗氧量测量显示，经过50天的测试期，生物降解率高达70%，显示出较高的生物降解性。测定生物降解试验后的总有机碳量（TOC）。所获得的数值被发现低于对照组（系统中只有活性污泥），这表明可溶性生物降解中间体在环境中残留的可能性变得可以忽略不计。

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.