Preparation of biodegradable plastics from cellulose acetate and their application to fiber and foam

通过开环接枝共聚环酯以及与生物可降解热塑性塑料共混，将二乙酸纤维素（CDA）转化为热塑性塑料。对于前者，通过极化显微镜观察、DSC和熔融粘弹性测量等方法，详细研究了产物的基本性质，包括接枝量、接枝支链长度、接枝链构造结构、结晶度以及微相分离特性。结果表明：(1)根据不同的环酯种类和引入的链长，开环接枝共聚可以得到从玻璃态聚合物到弹性体等不同类型的室温下塑料；(2)引入的接枝支链之间产生自组装，并随着链长的增加而增强，从而导致其结晶；(4)引入的接枝链与CDA的接枝位点结合，抑制了接枝链之间的结晶作用；(3)引入的接枝链长度增加到一定限度后，其组装效应超过了热塑化效应，导致室温下强度的增加；(5)当引入的支链的化学结构因不同环酯的混合接枝共聚而变得不规则时，这些现象变得难以识别，并且可以获得有效的塑化和脱结晶。支链之间的相互作用以及它们作为混凝剂的强度特性被认为非常符合酰化纤维素的事实。随着酰基碳数的增加，热流温度和强度先降低，经过最低值后再升高。对于后者，以乙酰化丙酰化纤维素为中心的合成聚合物与纤维素衍生物的共混得到了广泛的研究，并在分子水平上得到了它们共混状态的相应发现，其中甚至可以找到相容的共混物。作为产品功能性开发的一部分，对其纤维成形性能进行了研究。在这种情况下，虽然获得了一种有用和重要的分析方法，但塑化cda的纤维形成性能不是很好，不能与具有结晶主链的聚合物相比。少

Cellulose diacetate (CDA) was intended to convert into thermoplastics by ring-opening graft-co-polymerization of cyclic esters as well as by blending with biodegradable thermoplastics. For the former, fundamental properties of the products including grafted amounts, grafted branch chain lengths, constructed structures of the grafted chains, crystallinity, as well as the micro phase separation characteristics were investigated in detail through polarized microscopic observations, DSC and melt-viscoelastic measurements and so forth. As the results, (1) various types of plastics, ranging from glassy state polymers to elastomers at room temperature, could be easily obtained by the ring-opening graft-co-polymerization, depending on the species of cyclic esters used and the introduced chain length, (2) self-assembly among the introduced grafted branch chains was developed, which was strengthened with an increase in the chain length resulting in their crystallization, (3) when the introduced … More chain length enlarged more than certain limited amounts, their assembly effect exceeded the thermoplasticization effect, resulting in the strength increases revealed at room temperature, (4) this crystallization among the introduced graft-chains was repressed by their binding to the grafting sites of CDA, (5) these phenomena became unrecognizable when the chemical structure of the introduced branch chains turned to be irregular as the result of mixed graft-co-polymerization of different cyclic esters, and effective plasticization and decrystallization could be obtained These interaction among the branch-chains as well as their strength properties as coagulates are considered to correspond very well to the fact, being known to acylated cellulose, that the thermal-flow temperature and the strength are first decrease, passing through minimum points, and then increase with the increase in the carbon number of the acyl group. In the case of the latter, blends of synthetic polymers and cellulose derivatives, centering on acetylated propionylated cellulose, have widely carried out, and the corresponding findings for their blending states in molecular level could be obtained, among which even compatible blends could be found. As a functionality development of the products, the fiber forming property was studied. For this case, while a useful and important analyzing methodology for this evaluation was obtained, the fiber forming property for the plasticized CDAs is not so good and not comparable to polymers having crystalline main chains. Less