热固性聚合物
辅助
材料科学
复合材料
热塑性塑料
极限抗拉强度
聚氨酯
作者
Zhongkai Guo,Zhaoxing Dong,Junpeng Gao,Hao Zhang,Baoyan Zhang,Min‐Hui Li,Jun Hu
出处
期刊:Small
[Wiley]
日期:2024-09-23
标识
DOI:10.1002/smll.202406876
摘要
Auxetic foams with a negative Poisson's ratio (NPR) have attracted considerable attention in material engineering due to their outstanding performance in seismic and energy absorption. Nevertheless, thermoplastic auxetic foams are compromised by weak non-covalent crosslinking that diminishes the mechanical strength and durability of foams. Conversely, thermosetting foams with chemical crosslinking, although mechanically robust, face challenges in elaborating auxetic structure and in achieving recyclability. Herein, an alternative approach is proposed to tackle this dilemma by incorporating dynamic disulfide bonds into the polymer network for preparing a thermosetting polyurethane foam with covalent adaptable network. By leveraging the unidirectional multi-effect compression technique, the topological network reorganization of foam is induced, transforming the initial circular open-cell structure into a re-entrant cell structure. This structural transformation endows the foam with stable NPR capability, achieving a minimum Poisson's ratio value of -0.4 within 30% compressive strain. Benefiting from its reinforced network structure, the foam also demonstrates high compressive strength (6.47 MPa) and tensile strength (1.67 MPa). Furthermore, it is recyclable and can be recompressed into thermosetting films. This work offers a straightforward approach to making auxetic thermosetting foams with good mechanical and recyclable properties, which is interesting for the development of high-performance auxetic materials.
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