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

在双螺杆挤出机上进行了ε-己内酯与二醋酸纤维素开环接枝共聚反应。对所得产物进行了物化性能评价。结果表明，所制得的复合材料具有良好的疏水性、生物降解性和实用的物理性能。另一方面，在酚类和多元醇的存在下，各种生物质的液化以及这些液化产物转化为苯酚和氨基甲酸酯树脂的实验结果已经积累。其中，利用从环境中分离得到的微生物进行体外生物降解试验，以从麸皮液化产品中获得的聚氨酯泡沫作为样品。例如，经过118天的生物降解试验后，与对照试验相比，重量损失约为8%。相应样品的扫描电子显微镜观察证实了生物降解的发生。红外光谱分析表明，样品中发生了醚键断裂，但氨基甲酸酯键断裂并未引起任何变化。通过对发酵液的高效液相分析，得到了与对照结果不同的成分，进一步证实了样品的生物降解性。另一方面，在封闭系统中的氧耗测量表明，在试验期50天后，可生物降解性高达70%，表现出较高的可生物降解性。所得结果低于对照(只有活性污泥的系统)，这表明可溶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.