不同水环境下塑料生物降解一致性评价体系建立及其降解机理研究

针对不同自然水环境中由于水质、微生物种群等不同而造成同种生物降解塑料表现出不同降解行为，及其含相同特征基团、不同重复单元的聚合物和改性产物在同一水环境中降解性能差异性的现象，项目拟建立模拟实际淡水和海水的实验室测试装置与方法，构建同种材料在不同水环境下降解性能一致性评价体系，以常见生物降解聚酯及其共聚物和共混物为研究对象，通过测定降解产物生物气体来测得降解率，清晰水环境条件对降解性能的影响机制；通过降解过程中关键微生物降解酶鉴定与表达，清晰酶促降解与非酶促降解机理，结合对降解残样及产物含量、分子结构及性能的表征，建立不同组分塑料降解动力学模型和探究其降解机理。通过研究，确立一种模拟实际水环境条件下建立塑料降解动力学模型的方法，并将其用于降解速率的模拟预测，从而为制备水环境中降解可控塑料的分子结构设计提供新思路和打下科学基础。

In view of the different degradation behaviors of the same biodegradable plastics caused by water quality and microbial populations in different natural water environments, polymers and their modified products which containing the same characteristic groups while with different repetitive units always show different degradation performance in the same water environment. The aim of this project is to establish the laboratory testing devices and methods to simulate the actual fresh water and sea water, and construct the consistency evaluation system of degradation performance of the same material in different water environment. In this project, common biodegradable polyesters and their copolymers and blends will be as the research object. The degradation rate of these polymers will be measured by the determination of biogas, and the influence mechanism of water environmental conditions on the degradation performance was clarified. Through the identification and expression of key microbial degrading enzymes in the degradation process, the mechanisms of enzymatic and non-enzymatic degradation will be clarified. Combined with the characterization of degradation residue and product content, molecular structure and properties, the degradation kinetic model of plastics with different components will be established as well as its degradation mechanism will be explored. With this study, a method of establishing the kinetic model of plastic degradation under the condition of simulating the actual water environment will be established, and it will be used to simulate and predict the degradation rate of biodegradable plastics. As a result, this project will provide a new idea and lay a scientific foundation for the molecular structure design of degradable controllable plastics in water environment.