scholarly journals Multi-Material 3D Printed Shape Memory Polymer with Tunable Melting and Glass Transition Temperature Activated by Heat or Light

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 710 ◽  
Author(s):  
Ela Sachyani Keneth ◽  
Rama Lieberman ◽  
Matthew Rednor ◽  
Giulia Scalet ◽  
Ferdinando Auricchio ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Shape Memory ◽  
Smart Materials ◽  
Shape Memory Polymer ◽  
3D Structure ◽  
Three Dimensional ◽  
Shape Memory Polymers ◽  
Practical Applications ◽  
Different Temperatures ◽  
Robotic Devices

Shape memory polymers are attractive smart materials that have many practical applications and academic interest. Three-dimensional (3D) printable shape memory polymers are of great importance for the fabrication of soft robotic devices due to their ability to build complex 3D structures with desired shapes. We present a 3D printable shape memory polymer, with controlled melting and transition temperature, composed of methacrylated polycaprolactone monomers and N-Vinylcaprolactam reactive diluent. Tuning the ratio between the monomers and the diluents resulted in changes in melting and transition temperatures by 20, and 6 °C, respectively. The effect of the diluent addition on the shape memory behavior and mechanical properties was studied, showing above 85% recovery ratio, and above 90% fixity, when the concentration of the diluent was up to 40 wt %. Finally, we demonstrated multi-material printing of a 3D structure that can be activated locally, at two different temperatures, by two different stimuli; direct heating and light irradiation. The remote light activation was enabled by utilizing a coating of Carbon Nano Tubes (CNTs) as an absorbing material, onto sections of the printed objects.

Thermo-Mechanical Behavior of Epoxy Shape Memory Polymer

2013 ◽  
Vol 721 ◽  
pp. 169-172 ◽  
Author(s):  
Yu Gu ◽  
Shao Xiong Li
Keyword(s):  
Mechanical Behavior ◽  
Shape Memory ◽  
Significant Influence ◽  
Smart Materials ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Testing Temperature ◽  
Curing Agent ◽  
Different Temperatures ◽  
Viscoelastic Behaviors

The viscoelastic behaviors of shape memory polymers have a significant influence on the function realization of this kind of smart materials. In this study, stress-strain hysteresis under uniaxial tension of epoxy shape memory polymers with varied curing agent contents and types were tested at different temperatures. The effects of the testing temperature, curing-agent type and content on the viscoelastic behaviors of the materials were discussed.

Three-dimensional Graphene Coated Shape Memory Polyurethane Foam with Fast Responsive Performance

2021 ◽  
Author(s):  
Tianjiao Wang ◽  
Jun Zhao ◽  
Chuanxin Weng ◽  
Tong Wang ◽  
Yayun Liu ◽  
...  
Keyword(s):  
Shape Memory ◽  
Polyurethane Foam ◽  
Three Dimensional ◽  
Shape Memory Polymers ◽  
Practical Applications ◽  
External Stimuli ◽  
Shape Memory Polyurethane

Shape memory polymers (SMPs) that change shapes as designed by external stimuli have become one of the most promising materials as actuators, sensors, and deployable devices. However, their practical applications...

Shape Memory Behavior of Carbon Composites With Functional Interlayer

2018 ◽  
Author(s):  
L. Santo ◽  
L. Iorio ◽  
G. M. Tedde ◽  
F. Quadrini
Keyword(s):  
Carbon Fiber ◽  
Shape Memory ◽  
Polymer Composites ◽  
Polymer Matrix ◽  
Smart Materials ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Carbon Composites ◽  
Three Point Bending ◽  
Functional Behavior

Shape Memory Polymer Composites (SMPCs) are smart materials showing the structural properties of long-fiber polymer-matrix together with the functional behavior of shape memory polymers. In this study, SM carbon fiber reinforced (CFR) composites have been produced by using a SM interlayer between two CFR prepregs. Their SM properties have been evaluated in comparison with traditional structural CFR composites without the SM interlayer by using an especially designed test. Active and frozen forces are measured during a thermo-mechanical cycle in the three-point bending configuration. Experimental results show that SMPCs are able to fix a temporary deformed shape by freezing high stresses.

scholarly journals Shape-Memory Polymeric Artificial Muscles: Mechanisms, Applications and Challenges

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4246 ◽  
Author(s):  
Yujie Chen ◽  
Chi Chen ◽  
Hafeez Ur Rehman ◽  
Xu Zheng ◽  
Hua Li ◽  
...  
Keyword(s):  
Shape Memory ◽  
Smart Materials ◽  
Recent Progress ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Artificial Muscles ◽  
Linkage Design ◽  
Wide Range ◽  
Liquid Crystal Elastomers ◽  
Made In

Shape-memory materials are smart materials that can remember an original shape and return to their unique state from a deformed secondary shape in the presence of an appropriate stimulus. This property allows these materials to be used as shape-memory artificial muscles, which form a subclass of artificial muscles. The shape-memory artificial muscles are fabricated from shape-memory polymers (SMPs) by twist insertion, shape fixation via Tm or Tg, or by liquid crystal elastomers (LCEs). The prepared SMP artificial muscles can be used in a wide range of applications, from biomimetic and soft robotics to actuators, because they can be operated without sophisticated linkage design and can achieve complex final shapes. Recently, significant achievements have been made in fabrication, modelling, and manipulation of SMP-based artificial muscles. This paper presents a review of the recent progress in shape-memory polymer-based artificial muscles. Here we focus on the mechanisms of SMPs, applications of SMPs as artificial muscles, and the challenges they face concerning actuation. While shape-memory behavior has been demonstrated in several stimulated environments, our focus is on thermal-, photo-, and electrical-actuated SMP artificial muscles.

A comprehensive review on thermomechanical constitutive models for shape memory polymers

2020 ◽  
Vol 31 (10) ◽  
pp. 1243-1283 ◽  
Author(s):  
Ebrahim Yarali ◽  
Ali Taheri ◽  
Mostafa Baghani
Keyword(s):  
Shape Memory ◽  
Smart Materials ◽  
Constitutive Equations ◽  
Constitutive Relations ◽  
Shape Memory Polymer ◽  
Constitutive Models ◽  
Shape Memory Polymers ◽  
Typical Application ◽  
Comprehensive Review ◽  
Thermally Responsive

Shape memory polymers are a class of smart materials, which are capable of fixing their deformed shapes, and can return to their original shape in reaction to external stimulus such as heat. Also due to their exceptional properties, they are mostly used in four-dimensional printing applications. To model and investigate thermomechanical response of shape memory polymers mathematically, several constitutive equations have been developed over the past two decades. The purpose of this research is to provide an up-to-date review on structures, classifications, applications of shape memory polymers, and constitutive equations of thermally responsive shape memory polymers and their composites. First, a comprehensive review on the properties, structure, and classifications of shape memory polymers is conducted. Then, the proposed models in the literature are presented and discussed, which, particularly, are focused on the phase transition and thermo-viscoelastic approaches for conventional, two-way as well as multi-shape memory polymers. Then, a statistical analysis on constitutive relations of thermally activated shape memory polymers is carried out. Finally, we present a summary and give some concluding remarks, which could be helpful in selection of a suitable shape memory polymer constitutive model under a typical application.

scholarly journals Self-Restoring Capacitive Pressure Sensor Based on Three-Dimensional Porous Structure and Shape Memory Polymer

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 824
Author(s):  
Byunggeon Park ◽  
Young Jung ◽  
Jong Soo Ko ◽  
Jinhyoung Park ◽  
Hanchul Cho
Keyword(s):  
Porous Structure ◽  
Shape Memory ◽  
Pressure Sensor ◽  
Shape Memory Polymer ◽  
Three Dimensional ◽  
Pressure Sensors ◽  
Capacitive Pressure Sensor ◽  
Practical Applications ◽  
Flexible Pressure Sensor ◽  
Sensing Performance

Highly flexible and compressible porous polyurethane (PU) structures have effectively been applied in capacitive pressure sensors because of the good elastic properties of the PU structures. However, PU porous structure-based pressure sensors have been limited in practical applications owing to their low durability during pressure cycling. Herein, we report a flexible pressure sensor based on a three-dimensional porous structure with notable durability at a compressive pressure of 500 kPa facilitated by the use of a shape memory polymer (SMP). The SMP porous structure was fabricated using a sugar templating process and capillary effect. The use of the SMP resulted in the maintenance of the sensing performance for 100 cycles at 500 kPa; the SMP can restore its original shape within 30 s of heating at 80 °C. The pressure sensor based on the SMP exhibited a higher sensitivity of 0.0223 kPa−1 than a typical PU-based sensor and displayed excellent sensing performance in terms of stability, response time, and hysteresis. Additionally, the proposed sensor was used to detect shoe insole pressures in real time and exhibited remarkable durability and motion differentiation.

Influence of Radialization Dosage on Shape Memory Effect of Polystyrene Copolymer

2008 ◽  
Vol 47-50 ◽  
pp. 690-693 ◽  
Author(s):  
Da Wei Zhang ◽  
Jin Song Leng ◽  
Yan Ju Liu
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Smart Materials ◽  
Shape Recovery ◽  
Memory Performance ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Mechanical Analysis ◽  
Styrene Copolymer

This paper is concerned about the synthesis of shape memory styrene copolymer and the investigation of the influence of radialization dosage on its shape memory effect. As one of novel actuators in smart materials, shape memory polymers (SMPs) have been investigated intensively. Styrene copolymer with proper cross-linking degree can exhibit shape memory effect (SME). In this paper, the influence of radialization on shape memory effect of styrene copolymer was investigated through altering the dosage of radialization. The radialization dosage of styrene copolymer was determined by changed radicalization time. The glass transition temperature (Tg) of styrene copolymerwas measured by Dynamic Mechanical Analysis (DMA). The shape memory performance of styrene copolymer with different radiated dosage was also evaluated. Results indicated that the shape memory polymer (SMP) was synthesized successfully. The Tg increased from 60°C to 65°C followed by increasing the radialization dosage. Moreover, the SMP experienced good SME and the largest reversible strain of the SMP reached as high as 150%. When heating above Tg+30°C (different copolymers performed different Tg), the shape recovery speed of the copolymers increased with increasing the radialization dosage. However, the recovery speed decreased with increasing the radialization dosage at the same temperature of 95°C.

scholarly journals Frozen Stresses in Shape Memory Polymer Composites

2018 ◽  
Vol 55 (4) ◽  
pp. 494-497
Author(s):  
Giovanni Matteo Tedde ◽  
Loredana Santo ◽  
Denise Bellisario ◽  
Leandro Iorio ◽  
Fabrizio Quadrini
Keyword(s):  
Shape Memory ◽  
Polymer Composites ◽  
Smart Materials ◽  
Polymer Matrix Composites ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Experimental Tests ◽  
Matrix Composites ◽  
Flexural Test ◽  
Functional Behavior

Shape Memory Polymer Composites (SMPCs) are a class of smart materials in which the structural properties of long-fiber polymer-matrix composites and the functional behavior of Shape Memory Polymers (SMP) are combined together. In this study, the frozen stresses resulting from fixing a deformed shape have been investigated. Two different samples were manufactured, with and without significant shape memory properties, and a three point flexural test equipment was used in order to fix a deformed shape. The forces and the resulting stresses were measured during the samples deformation and after the shape freezing. The experimental tests have shown that the shape memory sample has a better ability to fix a deformed shape, since its frozen stress is higher in all the tests.

Numerical investigation of smart auxetic three-dimensional meta-structures based on shape memory polymers via topology optimization

2020 ◽  
Vol 31 (15) ◽  
pp. 1838-1852
Author(s):  
Ehsan Jebellat ◽  
Majid Baniassadi ◽  
Alireza Moshki ◽  
Kui Wang ◽  
Mostafa Baghani
Keyword(s):  
Topology Optimization ◽  
Shape Memory ◽  
Smart Materials ◽  
Poisson’S Ratio ◽  
Compressive Strain ◽  
Three Dimensional ◽  
Shape Memory Polymers ◽  
Poisson's Ratio ◽  
Negative Poisson’S Ratio ◽  
Negative Poisson's Ratio

Today, the human being endeavors to manufacture devices and materials capable of doing something in an intelligent way. Shape memory polymers are a series of smart materials, capable of retrieving their original shape from a temporary form by applying external stimuli, for example, heat, electricity, magnetism, light, pH, and humidity. In this research, the behavior of temperature-sensitive shape memory polymer–based structures with positive and negative Poisson’s ratio has been analyzed. The purpose is the material design of smart structures with tunable Poisson’s ratio using topology optimization. In this study, a meta-structure is designed, which is made by a smart material. Not only does this structure have shape memory effects, but also it has negative Poisson’s ratio, which can be used in new sensors, actuators, and biomedical applications. After creation of the unit cell and the representative volume element and formation of final three-dimensional structure, finite element modeling is conducted based on a thermo-visco-hyperelastic constitutive model at large deformations. Examining the behavior of structures in tensile pre-strains of 20%, 10%, and 5%, it is observed that pre-strain has no considerable effect on Poisson’s ratio, but under compressive strain of 20%, it is concluded that the type of loading is effective on Poisson’s ratio and the results are different in tension and compression modes. Finally, the influence of temperature rate on the behavior of structures is inspected, and it is concluded that the more slowly the temperature changes, the more strain or shape recovery is accomplished at a specific temperature.

Thermal Activation of Shape Memory Polymers Through Vascular Means

2011 ◽  
Author(s):  
David M. Phillips ◽  
Jeffery W. Baur
Keyword(s):  
Shape Memory ◽  
Environmental Conditions ◽  
Thermal Activation ◽  
Analytical Modeling ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Practical Applications ◽  
Heating And Cooling ◽  
Model Predictions ◽  
Vascular Channels

Thermal activation of shape memory polymers requires a heating mechanism that will achieve a temperature range that exceeds a minimum triggering temperature but does not overheat the material. In laboratory practice, ovens are typically used to achieve a uniform temperature during testing. In practical applications, active heating schemes must be utilized that are robust enough to handle changing environmental conditions. In this work, we analyze the intricacies of vascular heating and cooling methodologies for shape memory polymers operating in an open environment. Our methodology is based on analytical modeling of the steady state surface temperature of shape memory polymers that incorporate vascular channels. With the material properties and environmental conditions, the model is used to predict appropriate channel geometry for triggering the shape memory polymer. Thermography is used to verify the model predictions for real systems of shape memory polymers.

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