UV Reconfigurable Shape Memory Polyurethane with a High Recovery Ratio under Large Deformation

Abstract

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 °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.

Photo‐Controlled [4+4] Cycloaddition of Anthryl‐Polymer Systems: A Versatile Approach to Fabricate Functional Materials

“…The cross‐linked PDLLA‐PTMEG‐An network sets the permanent form of the material and the two thermal transition temperatures (T m , PTMEG and T g , PDLLA) gave temporary shapes and allowed recovery of the original shape. Similarly, Tian and co‐workers utilized BHEAA to introduce anthryl groups onto pre‐polymers of methylene diphenyl diisocyanate and polycaprolactone diol (Figure 9, structure 7) to create cross‐linked shape memory polymer [55] …”

“…[50] Polymers based on methylene diphenyl diisocyanate, polycaprolactone diol and BHEAA (7). [55] Anthracene-containing epoxy elastomers (8). [56] Poly(aryl ether ketone) post-modified with anthracene side groups (9).…”

“…Similarly, Tian and co-workers utilized BHEAA to introduce anthryl groups onto pre-polymers of methylene diphenyl diisocyanate and polycaprolactone diol (Figure 9, structure 7) to create cross-linked shape memory polymer. [55] Rios et al [56] and Liu et al [57] developed shape-memory polymers using different polymeric backbone. A light-and heattriggered shape memory polymer based on anthracene-containing epoxy elastomers was studied by Rios et al [56] The polymeric material fabricated by curing the pre-synthesized 9anthracenemethoxyl glycidyl ether with 1,4-butanediol diglycidyl ether and sebacic acid (Figure 9, structure 8), exhibits shape fixation and recovery that can be induced by UV light irradiation (365 nm) and heating to 130 °C, respectively.…”

“…Polyurethane based on polycaprolactone diol and 4,4-methylenebis (cyclohexyl isocyanate) fused with 1,4-butanediol and anthracene-containing diol (6) [50]. Polymers based on methylene diphenyl diisocyanate, polycaprolactone diol and BHEAA (7) [55]. Anthracene-containing epoxy elastomers (8) [56].…”

High performance polylactic acid/thermoplastic polyurethane blends with in‐situ fibrillated morphology

“…As the morphology of TPU can be changed by altering the processing temperature due to the excellent deformation capacity, the formation of in-situ fibrillated TPU is considered for the following reason. 45 Under the conditions of appropriate processing temperature (200 C), the molecular chain of TPU will not break but will deform itself. It is worth noting that the fibrillated TPU is directionally distributed in the matrix with shear direction in melt-blending.…”