Shape Recovery Characteristics of 3D Printed Soft Polymers and Their Composites

2016 ◽  
Author(s):  
Wenbo Liu ◽  
Nan Wu ◽  
Kishore Pochiraju
Keyword(s):  
High Resolution ◽  
Shape Memory ◽  
Recovery Time ◽  
Shape Recovery ◽  
Recovery Process ◽  
Hot Water ◽  
Recovery Ratio ◽  
3D Printed ◽  
Term Creep

Shape memory polymers can be triggered to assume memorized shapes from temporarily deformed forms using thermal stimuli. This paper focuses on the characterization of the shape memory behaviors observed in selected 3D printable photo-cured polymer parts and filament with specified fillers. The shape recovery ratio and recovery time were analyzed using 3D printed specimens with 90° bends. Parts with the mixture of selected commercially available polymers — a rigid polymer (RP) and two digitally mixed polymer blends (DB-A and DB-B) were 3D-printed on a multi-material 3D printer capable of producing digital materials with variable mix ratios. The recovery ratios were determined after thermal triggering and after long-term creep (self-recovery) without thermal triggering. The 3D printed parts were heated to above their glass transaction temperature to train temporary shapes and the recovery of original shapes after a thermal trigger was monitored using a high-resolution camera. Long-term self-recovery (non-triggered) was also studied by observing the parts after temporary shape has been trained, as the try to regain their original shape over several days of slow recovery. The recovery of bending angles was quantitatively recorded from the images taken during the shape recovery process. The recovery due to thermal triggers was monitored under a high resolution microscope by reheating with hot water at 90°C. Experiments of long-term self-recovery at room temperature included monitoring of several parts by taking periodic images of the specimens using a resolution camera. The effect of inclusion of fillers on the shape recovery characteristics was also investigated. Silicon Carbide (SiC) with different weight fractions were mixed into PLA powders. Continuous filaments were extruded using a single screw extruder. The recovery time of thermal activation recovery was then characterized to determine the effect of addition of the fillers. The effect of material-mix ratio, initial printed orientation, filler type on the recovery ratio and recovery time are described in this paper.

Tunable shape recovery progress of thermoplastic polyurethane by solvents

2018 ◽  
Vol 47 (1) ◽  
pp. 7-13 ◽  
Author(s):  
Changchun Wang ◽  
Bo Kou ◽  
Zusheng Hang ◽  
Xuejuan Zhao ◽  
Tianxuan Lu ◽  
...  
Keyword(s):  
Shape Memory ◽  
Internal Stress ◽  
Recovery Time ◽  
Shape Recovery ◽  
Thermoplastic Polyurethane ◽  
Recovery Process ◽  
Solubility Parameters ◽  
Content Type ◽  
Shape Memory Properties ◽  
Residual Strains

Purpose This study aims to present that the chemo-responsive shape recovery of thermoplastic polyurethane (TPU) is tunable by solvents with different solubility parameters, and it is generic for chemo-responsive shape-memory polymer and its composites. Design/methodology/approach Two kinds of commercial TPU samples with different thicknesses were prepared by panel vulcanizer and injection molding (an industrial manner) to investigate their chemo-responsive shape memory properties in acetic ether and acetone. Findings Results showed that all of TPU films with different thicknesses can fully recover their original shapes weather they recover in acetic ether or acetone. But the recovery time of TPU films in acetone is greatly reduced, especially for the twisting samples. The residual strains of recovery TPU samples after extension reduce obviously. Research limitations/implications The great decrement of recovery time is related to two factors. One is due to the bigger solubility parameter of acetone with higher dipole moment compared with those of acetic ether, and the other is the remained internal stress of TPU films after preparation. The internal stress is identified to have an effect on the shape-memory properties by comparing the recovery process of samples with/without annealing. The reduced residual strains of recovery TPU samples after extension is due to the increasing mobility of polymer segments after molecules of acetic ether penetrates into the polymeric chains. Originality/value This is a universal strategy to control the recovery process of shape-memory materials or composites. The underlying mechanism is generic and should be applicable to chemo-responsive shape-memory polymers or their composites.

Investigate of Electrical Conductivity of Shape-Memory Polymer Filled with Carbon Black

2008 ◽  
Vol 47-50 ◽  
pp. 714-717 ◽  
Author(s):  
Xin Lan ◽  
Jin Song Leng ◽  
Yan Ju Liu ◽  
Shan Yi Du
Keyword(s):  
Electrical Conductivity ◽  
Carbon Black ◽  
Shape Memory ◽  
Shape Recovery ◽  
Volume Fraction ◽  
Shape Memory Polymer ◽  
Recovery Process ◽  
Thermomechanical Properties ◽  
Electrically Conductive ◽  
New System

A new system of thermoset styrene-based shape-memory polymer (SMP) filled with carbon black (CB) is investigated. To realize the electroactive stimuli of SMP, the electrical conductivity of SMP filled with various amounts of CB is characterized. The percolation threshold of electrically conductive SMP filled with CB is about 3% (volume fraction of CB), which is much lower than many other electrically conductive polymers. When applying a voltage of 30V, the shape recovery process of SMP/CB(10 vol%) can be realized in about 100s. In addition, the thermomechanical properties are also characterized by differential scanning calorimetery (DSC).

Relationship between Annealing and Shape Memory Effect of Shape Memory Polyurethane

2014 ◽  
Vol 936 ◽  
pp. 140-144 ◽  
Author(s):  
Jia Ying ◽  
Masaaki Nishikawa ◽  
Masaki Hojo
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Shape Recovery ◽  
Length Change ◽  
Recovery Ratio ◽  
High Entropy ◽  
Change Of State ◽  
Relationship Of ◽  
Shape Memory Polyurethane

The relationship of annealing and shape memory effect of uniaxially oriented shape memory polyurethane was studied; meanwhile a new method of adjusting shape recovery ratio by annealing was proposed for further consideration. Experiments were designed to compare the influence on length change from annealing and shape memory effect with shape memory polyurethane film at 65°C. We found that for shape memory polyurethane which had residual strain from material processing procedure, annealing and shape memory effect have the same effect on its length change if they are both carried out at the same temperature. It is because annealing and shape memory effect have the same mechanism, which is the change of state from low conformational entropy states to the recovery of a stable high entropy state in the polymer. Moreover, it is proved by experiment that shape recovery ratio of shape memory polyurethane can be adjusted by annealing.

scholarly journals Nanoscale Mechanical Properties of Nanoindented Ni48.8Mn27.2Ga24 Ferromagnetic Shape Memory Thin Film

Scanning ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-5
Author(s):  
Xiaofei Fu ◽  
Chao Liu ◽  
Xili Lu ◽  
Xianli Li ◽  
Jingwei Lv ◽  
...  
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Martensitic Transformation ◽  
Magnetron Sputtering ◽  
Shape Memory ◽  
Room Temperature ◽  
Shape Recovery ◽  
Recovery Ratio ◽  
Dc Magnetron Sputtering ◽  
Ferromagnetic Shape Memory

The structure and nanoscale mechanical properties of Ni48.8Mn27.2Ga24 thin film fabricated by DC magnetron sputtering are investigated systematically. The thin film has the austenite state at room temperature with the L21 Hesuler structure. During nanoindentation, stress-induced martensitic transformation occurs on the nanoscale for the film annealed at 823 K for 1 hour and the shape recovery ratio is up to 85.3%. The associated mechanism is discussed.

scholarly journals Study of Shape Memory and Tensile Property of 3D Printed Sinusoidal Sample/Nylon Composite Focused on Various Thicknesses and Shape Memory Cycles

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1600 ◽  
Author(s):  
Shahbaj Kabir ◽  
Sunhee Lee
Keyword(s):  
Shape Memory ◽  
Tensile Property ◽  
Shape Recovery ◽  
Cycle Number ◽  
Shape Memory Property ◽  
Memory Property ◽  
Fused Deposition ◽  
Initial Modulus ◽  
3D Printed ◽  
Nylon Composite

This study evaluated the shape memory and tensile property of 3D-printed sinusoidal sample/nylon composite for various thickness and cycles. Sinusoidal pattern of five thicknesses: 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, and 1.0 mm were 3D-printed on nylon fabric by the fused deposition modeling (FDM) 3D printer using shape memory thermoplastic polyurethane (SMTPU). Afterward, shape memory and tensile property was investigated up to 50 shape memory cycles. The study found that 3D-printed sinusoidal sample/nylon composite had a 100% shape recovery ratio for various thicknesses up to 50 cycles. The average shape recovery rate gradually decreased from 3.0°/s to 0.7°/s whereas the response time gradually increased with the increase of a 3D-printed pattern thickness. The stress and initial modulus gradually increased with the increase of the cycle’s number. Thus, the shape memory property had a similar tendency for various cycles whereas the tensile property gradually increased with the increase of the cycle number. Moreover, this study demonstrated that this 3D-printed sinusoidal sample/nylon composite can go through more than 50 cycles without losing its tensile or shape memory property. This 3D-printed sinusoidal sample/nylon composite has vast potential as smart, reinforced, and protective clothing that requires complex three-dimensional shapes.

scholarly journals The Influence of Shape Changing Behaviors from 4D Printing through Material Extrusion Print Patterns and Infill Densities

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3754
Author(s):  
Seokwoo Nam ◽  
Eujin Pei
Keyword(s):  
Shape Memory ◽  
Recovery Time ◽  
Shape Recovery ◽  
Shape Memory Polymer ◽  
Material Extrusion ◽  
Concentric Pattern ◽  
Dimensional Printing ◽  
Recovery Result ◽  
Am Processes ◽  
Recovery Temperature

Four-dimensional printing (4DP) is an approach of using Shape Memory Materials (SMMs) with additive manufacturing (AM) processes to produce printed parts that can deform over a determined amount of time. This research examines how Polylactic Acid (PLA), as a Shape Memory Polymer (SMP), can be programmed by manipulating the build parameters of material extrusion. In this research, a water bath experiment was used to show the results of the shape-recovery of bending and shape-recovery speed of the printed parts, according to the influence of the print pattern, infill density and recovery temperature (Tr). In terms of the influence of the print pattern, the ‘Quarter-cubic’ pattern with a 100% infill density showed the best recovery result; and the ‘Line’ pattern with a 20% infill density showed the worst recovery result. The ‘Cubic-subdivision’ pattern with a 20% infill density demonstrated the shortest recovery time; and the ‘Concentric’ pattern with a 100% infill density demonstrated the longest recovery time. The results also showed that a high temperature and high infill density provided better recovery, and a low temperature and low infill density resulted in poor recovery.

scholarly journals The Influence of Water and Solvent Uptake on Functional Properties of Shape-Memory Polymers

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Ehsan Ghobadi ◽  
Axel Marquardt ◽  
Elias Mahmoudinezhad Zirdehi ◽  
Klaus Neuking ◽  
Fathollah Varnik ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Recovery ◽  
Shape Memory Polymers ◽  
Holding Time ◽  
Fickian Diffusion ◽  
Recovery Ratio ◽  
Solvent Uptake ◽  
Time Shape ◽  
Influence Of Water ◽  
Shape Fixity

In this contribution, diffusion of water, acetone, and ethanol into a polymer matrix has been studied experimentally and numerically by finite element approaches. Moreover, the present study reports an assessment of different thermomechanical conditions of the shape-memory (SM) performance, for example, stress- or strain-holding times in stress- or strain-controlled thermomechanical cycles and the effect of maximum strain. According to the results presented here, the uptake of acetone in Estane is much higher than ethanol and follows classical Fickian diffusion. Further, a series of thermomechanical measurements conducted on dry and physically (hydrolytically) aged polyether urethanes revealed that incorporation of water seems to have an appreciable impact on the shape recovery ratios which can be attributed to the additional physical crosslinks. However, no obvious difference in shape fixation of dry and physically (hydrolytically) aged samples could be recognized. Furthermore, by decreasing the strain-holding time, shape recovery improves significantly. Moreover, the shape fixity is found to be independent of holding time. The shape recovery ratio decreased dramatically with an increase in the stress-holding time.

Heat Recovery Time of Adsorption Cooling System

2018 ◽  
Vol 26 (02) ◽  
pp. 1850014 ◽  
Author(s):  
Xuan Quang Duong ◽  
Ngoc Vi Cao ◽  
Jae Dong Chung
Keyword(s):  
Recovery Time ◽  
Heat Recovery ◽  
Cooling System ◽  
Recovery Process ◽  
Finned Tube ◽  
Hot Water ◽  
Two Dimensional ◽  
Cycle Times ◽  
Tube Type ◽  
Adsorption Cooling System

In this study, a two-dimensional numerical model of finned-tube type adsorbers was developed and used to examine heat recovery time to improve the performance of an adsorption cooling system. The optimal heat recovery time, which resulted in the highest COP, was determined for a range of heat source temperatures (60–90[Formula: see text]C) and cycle times (600–1200[Formula: see text]s). The introduced heat recovery process enhanced COP, but also reduced SCP. This penalty became more serious when the hot water temperature was low and cycle time was short, which serves as a guideline for when heat recovery should be adopted in a given operating condition.

scholarly journals Effect of Ta Additions on the Microstructure, Damping, and Shape Memory Behaviour of Prealloyed Cu-Al-Ni Shape Memory Alloys

Scanning ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Safaa N. Saud ◽  
E. Hamzah ◽  
H. R. Bakhsheshi-Rad ◽  
T. Abubakar
Keyword(s):  
Internal Friction ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Shape Recovery ◽  
Corrosion Current ◽  
Damping Capacity ◽  
Recovery Ratio ◽  
Shape Memory Behaviour ◽  
Current Densities ◽  
Number Of Cycles

The influence of Ta additions on the microstructure and properties of Cu-Al-Ni shape memory alloys was investigated in this paper. The addition of Ta significantly affects the green and porosity densities; the minimum percentage of porosity was observed with the modified prealloyed Cu-Al-Ni-2.0 wt.% Ta. The phase transformation temperatures were shifted towards the highest values after Ta was added. Based on the damping capacity results, the alloy of Cu-Al-Ni-3.0 wt.% Ta has very high internal friction with the maximum equivalent internal friction value twice as high as that of the prealloyed Cu-Al-Ni SMA. Moreover, the prealloyed Cu-Al-Ni SMAs with the addition of 2.0 wt.% Ta exhibited the highest shape recovery ratio in the first cycle (i.e., 100% recovery), and when the number of cycles is increased, this ratio tends to decrease. On the other hand, the modified alloys with 1.0 and 3.0 wt.% Ta implied a linear increment in the shape recovery ratio with increasing number of cycles. Polarization tests in NaCl solution showed that the corrosion resistance of Cu-Al-Ni-Ta SMA improved with escalating Ta concentration as shown by lower corrosion current densities, higher corrosion potential, and formation of stable passive film.

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