Studies on Developing Novel Biodegradable Polymeric Materials from Cellulose and Lignocellulosics

C.M.Buchanan和他的同事最近发现，取代度在2.5以上的纤维素乙酸酯在环境中是可降解的，其生物降解率受其取代度的影响。此外，从活性污泥和标记的纤维素酯中提取的自然设计的混合微生物培养物最终确定了纤维素醋酸酯的生物降解。这些观察结果强化了由纤维素醋酸酯引入可生物降解塑料的想法。现在需要的是丰富纤维素醋酸酯的热塑性，因为没有适当和合理的塑化，纤维素醋酸酯不能用作塑料。近几年来，西方研究人员用熔融共混法制备了纤维素酯和脂肪族聚酯的共混物。纤维素酯和聚酯的相容性是需要研究的主要问题，但…本研究的更多目标是以纤维素酯为原料制备实用的可生物降解塑料。在这种背景下，我们也一直在尝试以纤维素酯和醚类为原料，通过反应加工过程来开发可生物降解的塑料。这一过程包括保留一些羟基的纤维素衍生物或类似物的寡酯化反应。这会导致嫁接，也就是内部塑化。研究发现，当接枝量增大时，作为外部增塑剂的均低聚物的渗漏可以被抑制。在一定的扭矩作用下，在一定的扭矩作用下，二元酸酐与单环氧化物或甘油、己内酯和单环氧化物在较高的温度下熔融，得到可生物降解的塑料。在这一点上，可以开发一种新的技术，利用该技术可以定量地完全分离与CA化学键合的接枝低聚物和均一低聚物。在它的推广中，追求的是方法和条件，以提高嫁接量。较少

It has been found very recently by C.M.Buchanan and his coworkers that cellulose acetates with the degree of substitution up 2.5 are degradable in the environment and that the rate of biodegradation is influenced by its degree of substitution. Additionally, the biodegradation of cellulose acetates was conclusively established with a naturally devised mixed microbial culture derived from an activated sludge and ^<14>C labeled cellulose esters.These observations have strengthened the idea that biodegradable plastics can be introduced from cellulose acetates. What is needed now is enrichment of thermoplastic properties of the cellulose acetates, since, without proper and reasonable plasticization, cellulose acerate cannot be used as plastics.Blends of cellulose esters and aliphatic polyesters have been prepared during these several years by western investigators using melt compounding. Compatibility of the cellulose esters and the polyesters is the main subject to be investigated, but the … More object of this studies is to realize practical and biodegradable plastics from the cellulose esters. Under these background, we have been also trying to develop biodegradable plastics from cellulose esters and ethers by using a reactive processing procedure. This procedure includes oligoesterification of cellulose derivatives or likes with some hydroxyl groups remained. This causes a grafting, that is, an internal plasticization. It was found that the bleeding-out of the homo-oligomer, which is acting as external plasticizer, can be depressed, when the amounts of grafting become larger. Dicarboxylic acid anhydrides and monoepoxides or glycerine, epsilon-caprolactum and monoepoxides are successfully reacted in the presence of cellulose acetates at a relatively high temperature under certain torque by which all the compounds are melted, resulting in biodegradable plastics. In this concern, a new technique could be developed, by which grafted oligomers chemically bonded to CA can be separated from homo-oligomers quantitatively and completely. In its extension, methodology and conditions are pursued to improve the amounts of grafting. Less