针对聚丁二酸丁二醇酯（PBS）由于线形分子结构导致熔体强度低、加工性能差、撕裂强度低，引入交联结构改性会造成熔体粘度过高等问题，本项目提出设计合成结合型PBS共价自适应网络（PBSC），利用交联网络调控熔体强与力学性能，利用动态共价键补偿因交联而丧失的流动性，获得独特结构且综合性能优异的生物降解PBS新材料。拟以多官能度的交联单体、含二硫键的动态共价键单体与丁二酸、丁二醇经熔融酯化-缩聚合成不同链结构、拓扑结构、交联密度与动态共价键含量的PBSC，系统研究共价自适应网络结构对PBSC熔体性质、结晶性能、应力松弛行为、重复加工性能、力学性能与生物降解性能等的影响，建立PBSC结构与性能关系，并探索其潜在应用。预期研究成果可丰富结合型动态共价网络设计合成与性能调控的相关理论，并为脂肪族聚酯的结构设计与高性能化提供新思路与新策略，为拓展PBS的应用奠定基础。因此，本项目兼具科学意义与应用价值。

The application of poly(butylene succinate) (PBS) was limited by its low melt strength and viscosity as well as poor tear strength, especially in the areas of biodegradable film and foam as their fabrication need high melt strength and viscosity. Crosslinking provides an efficient way to improve good way melt strength and mechanical properties of PBS. However, crosslinking would lead to very high melt viscosity even resulting in the loss of melt flowability, which still leads to poor thermal processability. In this project, we proposed a novel way to address this issue by incorporation of crosslinking structure and associative dynamic covalent bond. The crosslinking structure confers the polymer with high melt strength and excellent mechanical property, meanwhile, the associative dynamic covalent bond imparts flowability to the polymer through network rearrangement induced by exchange reaction of dynamic covalent bond. Thus, associative PBS covalent adaptable network (PBSC) with combined excellent melt property, processability, and mechanical property is anticipated in this way. We will synthesize a series of PBSC with different chain structures, network topologies, crosslink densities and dynamic covalent bond contents by changing the contents and structures of crosslinking monomer and disulfide containing monomer during reaction with succinic acid and 1,4-butanediol through melt condensation polymerization. We will investigate the effect of structure of associative covalent adaptable network on the rheology, crystallization, stress-relaxation behavior, reprocessability, mechanical properties and biodegradability of the PBSC in detail and establish the structure-property relationship of the PBSC as well as explore the potential application of the PBSC. Expected outcomes would not only enrich the fundamental principles for designed synthesis and property regulation of associative covalent adaptable networks but also provide theoretical foundation and technical support for structure design, high performance modification and practical application of aliphatic polyesters such as PBS. Therefore, the project is highly valuable from viewpoints of both scientific research and practical application.