Chemical cross-linking is commonly used to prevent slippage between molecular chains in shape memory polymers (SMPs) to improve shape return. However, chemical cross-linking makes SMPs less stretchable, and the disordered network structure reduces the ability of SMPs to maintain temporary shapes. To obtain ultra-high stretchability and better shape memory properties, a cyclic polymer (C-PTHF-OH) was introduced into the shape memory polyurethane (PUCX) network, and the PUCX network topology was controlled by adjusting the content of C-PTHF-OH molecular rings. PUC0.5 exhibited the highest shape fixation (99.9 %) and shape recovery (98.4 %), and the higher the content of the C-PTHF-OH molecular ring, the higher the elongation at break of the prepared PUCX, with a slight decrease in tensile strength. Compared to PUC0 (2000 % elongation at break and 32 MPa tensile strength) prepared from the linear polymer, PUC0.5 showed up to 2150 % elongation at break and 31 MPa tensile strength. This study provides new ideas for the design of network structures for SMPs and is a new paradigm introduced into the SMPs network by cyclic topological polymers.

中文翻译：

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基于环状聚四氢呋喃分子环的超高拉伸性和形状固定率形状记忆聚氨酯


化学交联通常用于防止形状记忆聚合物 (SMP) 中分子链之间的滑动，以改善形状恢复。然而，化学交联使得SMP的可拉伸性较差，无序的网络结构降低了SMP维持临时形状的能力。为了获得超高的拉伸性能和更好的形状记忆性能，将环状聚合物（C-PTHF-OH）引入到形状记忆聚氨酯（PUCX）网络中，并通过调节C-PTHF-OH的含量来控制PUCX网络拓扑结构。 OH分子环。 PUC0.5表现出最高的形状固定（99.9%）和形状恢复（98.4%），且C-PTHF-OH分子环含量越高，制备的PUCX的断裂伸长率越高，略有下降在拉伸强度方面。与由线性聚合物制备的PUC0（2000％断裂伸长率和32MPa拉伸强度）相比，PUC0.5表现出高达2150％断裂伸长率和31MPa拉伸强度。该研究为SMPs网络结构的设计提供了新的思路，是环状拓扑聚合物引入SMPs网络的新范式。