Rahmatabadi Davood, Aberoumand Mohammad, Soltanmohammadi Kianoosh, Soleyman Elyas, Ghasemi Ismaeil, Baniassadi Majid, Abrinia Karen, Zolfagharian Ali, Bodaghi Mahdi, Baghani Mostafa
School of Mechanical Engineering, University of Tehran, Tehran 14174, Iran.
Faculty of Processing, Iran Polymer and Petrochemical Institute, Tehran 14975, Iran.
Polymers (Basel). 2022 Dec 13;14(24):5446. doi: 10.3390/polym14245446.
In this study, a new strategy and design for achieving a shape memory effect (SME) and 4D printed two-layer composite structures is unveiled, thanks to fused deposition modeling (FDM) biomaterial printing of commercial filaments, which do not have an SME. We used ABS and PCL as two well-known thermoplastics, and TPU as elastomer filaments that were printed in a two-layer structure. The thermoplastic layer plays the role of constraint for the elastomeric layer. A rubber-to-glass transition of the thermoplastic layer acts as a switching phenomenon that provides the capability of stabilizing the temporary shape, as well as storing the deformation stress for the subsequent recovery of the permanent shape by phase changing the thermoplastic layer in the opposite direction. The results show that ABS-TPU had fixity and recovery ratios above 90%. The PCL-TPU composite structure also demonstrated complete recovery, but its fixity was 77.42%. The difference in the SME of the two composite structures is related to the transition for each thermoplastic and programming temperature. Additionally, in the early cycles, the shape-memory performance decreased, and in the fourth and fifth cycles, it almost stabilized. The scanning electron microscopy (SEM) photographs illustrated superior interfacial bonding and part integrity in the case of multi-material 3D printing.
在本研究中,通过对不具备形状记忆效应(SME)的商用长丝进行熔融沉积建模(FDM)生物材料打印,揭示了一种实现形状记忆效应和4D打印双层复合结构的新策略与设计。我们使用ABS和PCL这两种知名热塑性塑料,以及TPU作为弹性体长丝,以双层结构进行打印。热塑性塑料层对弹性体层起到约束作用。热塑性塑料层的橡胶态到玻璃态转变充当一种切换现象,它能够稳定临时形状,并通过使热塑性塑料层沿相反方向发生相变来存储变形应力,以便后续恢复永久形状。结果表明,ABS - TPU的固定率和回复率高于90%。PCL - TPU复合结构也展示出完全恢复,但它的固定率为77.42%。两种复合结构形状记忆效应的差异与每种热塑性塑料的转变以及编程温度有关。此外,在早期循环中,形状记忆性能下降,而在第四和第五个循环中,它几乎稳定下来。扫描电子显微镜(SEM)照片表明,在多材料3D打印的情况下,界面结合良好且部件完整性优异。