Shape-Memory Bionanocomposites Based on Chitin Nanocrystals and Thermoplastic Polyurethane with a Highly Crystalline Soft Segment

2013 ◽  
Vol 14 (12) ◽  
pp. 4475-4482 ◽  
Author(s):  
Ainara Saralegi ◽  
Susana C. M. Fernandes ◽  
Ana Alonso-Varona ◽  
Teodoro Palomares ◽  
E. Johan Foster ◽  
...  
Keyword(s):  
Shape Memory ◽  
Soft Segment ◽  
Thermoplastic Polyurethane

Polyurethane/Clay Shape Memory Nanocomposites Based on Palm Oil Polyol

2012 ◽  
Vol 576 ◽  
pp. 236-239 ◽  
Author(s):  
Syazana Ahmad Zubir ◽  
Ernie Suzana Ali ◽  
Sahrim Haji Ahmad ◽  
Norazwani Muhammad Zain ◽  
Soo Kai Wai
Keyword(s):  
Shape Memory ◽  
Palm Oil ◽  
Soft Segment ◽  
Thermoplastic Polyurethane ◽  
Clay Content ◽  
Weight Percent ◽  
Shape Memory Behavior ◽  
Crosslinking Process ◽  
The Matrix ◽  
Polyurethane Nanocomposites

Thermoplastic polyurethane (TPU) nanocomposites were prepared using polycaprolactonediol as the soft segment, 4,4’-diphenylmethane diisocyanate as the hard segment, 1,4-butanediol and palm oil polyol. Nanoclay with certain weight percent (wt%) was reinforced as filler to improve both mechanical and shape memory behavior of the nanocomposites. Palm oil polyol was introduced in order to provide hyperbranched structure for better dispersion of filler in the matrix as well as aiding the crosslinking process. The experimental results showed that the mechanical and shape memory behavior of clay reinforced polyurethane nanocomposites were influenced by clay weight percent in the polymer matrix. TPU with 3 wt% clay showed optimum values of mechanical properties while the shape memory behavior decreases with increasing clay content.

Physical property of 3D-printed sinusoidal pattern using shape memory TPU filament

2020 ◽  
Vol 90 (21-22) ◽  
pp. 2399-2410 ◽  
Author(s):  
Shahbaj Kabir ◽  
Hyelim Kim ◽  
Sunhee Lee
Keyword(s):  
Mechanical Properties ◽  
Tensile Test ◽  
Shape Memory ◽  
Fused Deposition Modeling ◽  
Loss Modulus ◽  
Thermoplastic Polyurethane ◽  
Heating Process ◽  
Fused Deposition ◽  
3D Printed ◽  
Sinusoidal Pattern

This study has investigated the physical properties of 3D-printable shape memory thermoplastic polyurethane (SMTPU) filament and its 3D-printed sinusoidal pattern obtained by fused deposition modeling (FDM) technology. To investigate 3D filaments, thermoplastic polyurethane (TPU) and SMTPU filament were examined by conducting infrared spectroscopy, x-ray diffraction (XRD), dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC) and a tensile test. Then, to examine the 3D-printed sinusoidal samples, a sinusoidal pattern was developed and 3D-printed. Those samples went through a three-step heating process: (a) untreated state; (b) 5 min heating at 70°C, cooling for 30 min at room temperature; and (c) a repeat of step 2. The results obtained by the three different heating processes of the 3D-printed sinusoidal samples were examined by XRD, DMTA, DSC and the tensile test to obtain the effect of heating or annealing on the structural and mechanical properties. The results show significant changes in structure, crystallinity and thermal and mechanical properties of SMTPU 3D-printed samples due to the heating steps. XRD showed the increase in crystallinity with heating. In DMTA, storage modulus, loss modulus and the tan σ peak position also changed for various heating steps. The DSC result showed that the Tg for different steps of the SMTPU 3D-printed sample remained almost the same at around 51°C. The tensile property of the TPU 3D-printed sinusoidal sample decreased in terms of both load and elongation with increased heating processes, while for the SMTPU 3D-printed sinusoidal sample, the load decreased but elongation increased about 2.5 times.

scholarly journals Shape-Memory-Recovery Characteristics of Microcellular Foamed Thermoplastic Polyurethane

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 351
Author(s):  
Chang-Seok Yun ◽  
Joo Seong Sohn ◽  
Sung Woon Cha
Keyword(s):  
Shape Memory ◽  
Cell Density ◽  
Shape Recovery ◽  
Structural Changes ◽  
Thermoplastic Polyurethane ◽  
Testing Machine ◽  
Base Material ◽  
Memory Mechanism ◽  
Foaming Process ◽  
Dog Bone

We investigated the shape-recovery characteristics of thermoplastic polyurethane (TPU) with a microcellular foaming process (MCP). Additionally, we investigated the correlation between changes in the microstructure and the shape-recovery characteristics of the polymers. TPU was selected as the base material, and the shape-recovery characteristics were confirmed using a universal testing machine, by manufacturing dog-bone-type injection-molded specimens. TPUs are reticular polymers with both soft and hard segments. In this study, we investigated the shape-memory mechanism of foamed polymers by maximizing the shape-memory properties of these polymers through a physical foaming process. Toward this end, TPU specimens were prepared by varying the gas pressure, foaming temperature, and type of foaming gas in the batch MCP. The effects of internal structural changes were investigated. These experimental variables affected the microstructure and shape-recovery characteristics of the foamed polymer. The generated cell density changed, which affected the shape-recovery characteristics. In general, a higher cell density corresponded to a higher shape-recovery ratio.

A shape memory alloy–actuated soft crawling robot based on adaptive differential friction and enhanced antagonistic configuration

2020 ◽  
Vol 31 (16) ◽  
pp. 1920-1934 ◽  
Author(s):  
Chen Liang ◽  
Yongquan Wang ◽  
Tao Yao ◽  
Botao Zhu
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Stride Length ◽  
Parametric Design ◽  
Thermoplastic Polyurethane ◽  
Interaction Mechanism ◽  
Experimental Tests ◽  
The Body ◽  
3D Printed ◽  
Miniature Robot

This article presents a soft crawling robot prototype with a simple architecture inspired by inchworms. The robot functionally integrates the torso (body) and feet in a monolithic curved structure that only needs a single shape memory alloy coil and differential friction to actuate it. A novel foot configuration is proposed, which makes the two feet, with an anti-symmetrical friction layout, can be alternately anchored, to match the contraction–recovery sequence of the body adaptively. Based on the antagonistic configuration between the shape memory alloy actuator and the elastic body, a vertically auxiliary spring was adopted to enhance the interaction mechanism. Force and kinematic analysis was undertaken, focusing on the parametric design of the special foot configuration. A miniature robot prototype was then 3D-printed (54 mm in length and 9.77 g in weight), using tailored thermoplastic polyurethane elastomer as the body material. A series of experimental tests and evaluations were carried out to assess its performance under different conditions. The results demonstrated that under appropriate actuation conditions, the compact robot prototype could accomplish a relative speed of 0.024 BL/s (with a stride length equivalent to 27% of its body length) and bear a load over five times to its own weight.

Shape memory thermoplastic polyurethane (TPU)/poly(ε-caprolactone) (PCL) blends as self-knotting sutures

2016 ◽  
Vol 64 ◽  
pp. 94-103 ◽  
Author(s):  
Xin Jing ◽  
Hao-Yang Mi ◽  
Han-Xiong Huang ◽  
Lih-Sheng Turng
Keyword(s):  
Shape Memory ◽  
Thermoplastic Polyurethane

Thermal and electroactive shape memory behaviors of poly(l-lactide)/thermoplastic polyurethane blend induced by carbon nanotubes

RSC Advances ◽  
2015 ◽  
Vol 5 (123) ◽  
pp. 101455-101465 ◽  
Author(s):  
Li-na Shao ◽  
Jian Dai ◽  
Zhi-xing Zhang ◽  
Jing-hui Yang ◽  
Nan Zhang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Shape Memory ◽  
Thermoplastic Polyurethane ◽  
Good Shape

Selectively located CNTs endowed the PLLA/TPU/CNT blend composites with good shape memory behaviors.

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