UV Reconfigurable Shape Memory Polyurethane with a High Recovery Ratio under Large Deformation
UV Reconfigurable Shape Memory Polyurethane with a High Recovery Ratio under Large Deformation
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大变形下具有高恢复率的紫外可重构形状记忆聚氨酯
DOI：
10.1021/acs.iecr.0c05036
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发表时间：
2021-01-27
影响因子：
4.2
通讯作者：
Tian, Ming
中科院分区：
文献类型：
--
作者：
Hu, Jing;Feng, Zhanbin;Tian, Ming
形状记忆热塑性聚氨酯（TPU）通常呈现相分离结构，其中硬链段通过氢键形成硬域，在形状恢复中发挥重要作用。然而，硬域中的物理相互作用总是很弱，导致永久变形，从而显着降低TPU的形状恢复能力。本研究合成了一种新型含蒽基二醇扩链剂，并将光响应性蒽基引入到TPU硬段中。通过蒽基团的光二聚作用，可以通过不同的紫外线照射时间来调节硬域的稳定性和可恢复性，即使应变达到270%，形状恢复率和形状固定率仍高于93%。更重要的是，无形状重构是通过紫外照射下蒽基团的二聚化实现的，从而实现了无需模板的三维（3D）形状的自由构建。因此，结合熔融转变，实现了从二维（2D）到3D的自发形状变化，并且蒽的脱二聚确保了聚氨酯在T = 150℃下的可回收性。这种简单易行的策略可用于制造在大变形下具有高形状固定/恢复比的可回收和光塑性形状记忆TPU，并将在支架中具有更广泛的潜在应用。
The shape memory thermoplastic polyurethane (TPU) generally exhibits a phase-separated structure, in which the hard segments form the hard domains via hydrogen bonds, and plays an important role in shape recovery. However, the physical interaction in the hard domains is always weak, resulting in a permanent deformation and thus decreasing the shape-recovery ability of TPU significantly. In this research, a new type of diol chain extender containing anthracene groups was synthesized, and the photoresponsive anthracene groups were incorporated into the hard segment of TPU. The stability in hard domains and recoverability could be tailored by different UV irradiation times via the photodimerization of anthracene groups, and the shape-recovery ratio and the shape-fixing ratio were still both above 93%, even when the strain reached 270%. More importantly, the shape-free reconfiguration is achieved through the dimerization of anthracene groups under UV irradiation, which achieved free construction of three-dimensional (3D) shapes without templates. Thus, the spontaneous shape change from two-dimensional (2D) to 3D was realized, in combination with melting transition, and the dedimerization of anthracene ensured the recyclability of polyurethane at T = 150 degrees C. This simple and facile strategy could be used to fabricate the recyclable and photoplasticity shape memory TPU with a high shape-fixing/recovery ratio at large deformation, and it would have a wider range of potential application in stents.