合成可降解功能聚乙烯的研究

The degradation of polyethylene material is a serious problem for human being's social development and ecological environment protection. Preparation of degradable polyethylene is an important way to solve this problem. The copolymerization of ethylene with monomers containing degradable groups to synthesize polyethylene with degradable units in the backbone is a promising method for the preparation of degradable polyethylene. As a potentially degradable monomer, the radical ring-opening polymerization of cyclic ketene acetal can prepare biodegradable polyester. Therefore, this project aims to develop a cobalt-mediated radical copolymerization system to copolymerize cyclic ketene acetal with ethylene for the synthesis of degradable polyethylene with ester groups in the backbone. The advantage of this system is that the ester group introduced by ring opening of cyclic ketene acetal has excellent biodegradability as well as the molecular weight of polyethylene and the content of ester group can be effectively controlled by the cobalt-mediated radical polymerization. This project intends to use this system to synthesize a series of polyethylene materials with different content of ester groups to establish the relationship between the content and distribution of ester groups and the degradation behavior of polyethylene. The smooth development of this project is expected to provide reliable basis for the development of new degradable polyethylene materials.

聚乙烯材料的降解是人类经济社会发展和生态环境保护绕不开的难题，制备可降解聚乙烯是解决这一问题的重要途径。将乙烯与含有可降解基团的单体共聚起来合成主链带有可降解单元的聚乙烯是可降解聚乙烯材料制备方法中具有潜力的一种。环烯酮缩醛作为一种具有潜在降解能力的单体，其自由基开环聚合可以制备可降解聚酯，因而本项目拟发展有机钴媒介的可控自由基聚合体系将其与乙烯共聚起来合成出主链含有酯基的可降解聚乙烯。该体系的优势在于由环烯酮缩醛开环引入的酯基具有优异的生物降解性能，另一方面利用有机钴媒介的自由基聚合可以有效地调控聚乙烯材料的分子量和酯基含量。本项目拟利用该体系合成一系列不同酯基含量、不同分子量的聚乙烯材料，并建立酯基含量、分布等与聚乙烯降解行为的关系。本项目的顺利开展有望为新型可降解聚乙烯材料的开发与应用提供思路与可靠依据。

聚乙烯材料的降解是人类经济社会发展和生态环境保护绕不开的难题，将乙烯与含有可降解基团的单体共聚起来合成主链带有可降解单元的聚乙烯是一种有潜力的解决聚乙烯材料降解问题的方法。本项目发展了有机钴以及二硫代胺基甲酸酯媒介的可控自由基聚合体系将环烯酮缩醛与乙烯共聚起来合成出主链含有酯基且酯基含量可调节的可降解聚乙烯。通过调控乙烯压强、初始环烯酮缩醛浓度以及有机钴或二硫代胺基甲酸酯浓度可以有效的控制聚合物的分子量和分子量分布，分子量可以达到5万以上。聚合物的降解能力也通过一系列实验和表征充分证明。此外，本项目还发展了自由基和阴离子机理相互可逆转化的杂化共聚体系，实现了本来无法共聚的环硫烷烃与极性烯类单体之间的共聚。本项目的研究成果为新型可降解聚乙烯材料的开发与应用以及新型共聚反应的构建提供思路与可靠依据。