Nanostructure-Dependent Marcus-Type Correlation of the Shape Recovery Rate and the Young’s Modulus in Shape Memory Polymer Aerogels

2018 ◽  
Vol 10 (27) ◽  
pp. 23321-23334 ◽  
Author(s):  
Suraj Donthula ◽  
Chandana Mandal ◽  
James Schisler ◽  
Theodora Leventis ◽  
Mary Ann B. Meador ◽  
...  
Keyword(s):  
Shape Memory ◽  
Young’S Modulus ◽  
Recovery Rate ◽  
Shape Recovery ◽  
Young's Modulus ◽  
Shape Memory Polymer

Multiscale Modeling of Light Activated Shape Memory Polymer

2008 ◽  
Author(s):  
Richard Beblo ◽  
Lisa Mauck Weiland
Keyword(s):  
Shape Memory ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Shape Memory Polymer ◽  
Scale Model ◽  
Cross Link ◽  
Material Response ◽  
Rotational Isomeric State ◽  
Stress Strain Relation ◽  
Cross Links

Presented is the development of a multi-scale model predicting the material response of a light activated shape memory polymer. Rotational Isomeric State (RIS) theory is used to build a molecular scale model of the polymer chain backbone, tracking the distances between cross-links. Cross-link to cross-link distances are then used with Boltzmann statistical mechanics to predict material response, generating Young’s modulus and stress-strain relation predictions. Young’s modulus is predicted by the model to be 0.049 and 3.2 MPa for the soft and hard states of the polymer respectively. Experimentally determined properties are also presented with reported moduli of 2.0 and 11.4 MPa in the soft and hard states respectively.

scholarly journals Determination of Shape Fixity and Shape Recovery Rate of Carbon Nanotube-filled Shape Memory Polymer Nanocomposites

2012 ◽  
Vol 41 ◽  
pp. 1641-1646 ◽  
Author(s):  
Shahrul Azam Abdullah ◽  
Aidah Jumahat ◽  
Nik Rosli Abdullah ◽  
Lars Frormann
Keyword(s):  
Carbon Nanotube ◽  
Shape Memory ◽  
Polymer Nanocomposites ◽  
Recovery Rate ◽  
Shape Recovery ◽  
Shape Memory Polymer ◽  
Shape Fixity

Characterization of shape memory polymer parts fabricated using material extrusion 3D printing technique

2019 ◽  
Vol 25 (2) ◽  
pp. 322-331 ◽  
Author(s):  
Carlos Alejandro Garcia Rosales ◽  
Hoejin Kim ◽  
Mario F. Garcia Duarte ◽  
Luis Chavez ◽  
Mariana Castañeda ◽  
...  
Keyword(s):  
Shape Memory ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Shape Memory Polymer ◽  
Strain Curve ◽  
Content Type ◽  
Layer Height ◽  
Material Extrusion ◽  
Process Output ◽  
Shape Fixity

Purpose Shape memory polymer (SMP) is capable of recovering its original shape from a high degree of deformation by applying an external stimulus such as thermal energy. This research presents an integration of two commercial SMP materials (DiAPLEX and Tecoflex) and a material extrusion (ME) printer to fabricate SMP parts and specimens. The material properties such as Young’s modulus of the specimens was examined as a process output. Furthermore, stress-strain curve, strain recovery, instant shape-fixity ratio, long-term shape-fixity ratio and recovery ratio of SMP specimens during a thermo-mechanical cycle were investigated. Design/methodology/approach The ME fabrication settings for the SMP specimens were defined by implementing a design of experiments with temperature, velocity and layer height as process variables. Findings It was found, according to main effect and iteration plots, that fabrication parameters have an impact on Young’s modulus and exist minimum iteration among variables. In addition, Young’s modulus variation of DiAPLEX and Tecoflex specimens was mostly caused by velocity and layer height parameters, respectively. Moreover, results showed that SMP specimens were able to recover high levels of deformation. Originality/value This paper is a reference for process control and for rheological properties of SMP parts produced by ME fabrication process.

Modeling the Thermoviscoelastic Properties and Recovery Behavior of Shape Memory Polymer Composites

2013 ◽  
Vol 81 (4) ◽  
Author(s):  
Stephen Alexander ◽  
Rui Xiao ◽  
Thao D. Nguyen
Keyword(s):  
Stress Response ◽  
Shape Memory ◽  
Polymer Composites ◽  
Young’S Modulus ◽  
Shape Recovery ◽  
Shape Memory Polymer ◽  
Strain Recovery ◽  
Recovery Stress ◽  
Recovery Behavior ◽  
Recovery Response

This work investigated the effects of stiff inclusions on the thermoviscoelastic properties and recovery behavior of shape memory polymer composites. Recent manufacturing advances have increased the applicability and interest in SMPCs made with carbon and glass inclusions. The resulting biphasic material introduces changes to both the thermal and mechanical responses, which are not fully understood. Previous studies of these effects have been concerned chiefly with experimental characterization and application of these materials. The few existing computational studies have been constrained by the limitations of available constitutive models for the SMP matrix material. The present study applied previously developed finite-deformation, time-dependent thermoviscoelastic models for amorphous SMPs to investigate the properties and shape memory behavior of SMPCs with a hexagonal arrangement of hard inclusions. A finite element model of a repeating unit cell was developed for the periodic microstructure of the SMPC and used to evaluate the temperature-dependent viscoelastic properties, including the storage modulus, tan δ, coefficient of thermal expansion, and Young's modulus, as well as the shape recovery response, characterized by the unconstrained strain recovery response and the constrained recovery stress response. The presence of inclusions in greater volume fractions were shown to lower both the glass transition and recovery temperatures slightly, while substantially increasing the storage and Young's modulus. The inclusions also negligibly affected the unconstrained strain recovery rate, while decreasing the constrained recovery stress response. The results demonstrate the potential of using hard fillers to increase the stiffness and hardness of amorphous networks for structural application without significantly affecting the temperature-dependence and time-dependence of the shape recovery response.

scholarly journals 4D Printing and Characterization of Shape Memory Polymer (SMP) Based Smart Gripper

2020 ◽  
Vol 5 (10) ◽  
pp. 1204-1211
Author(s):  
Francis Irungu Maina ◽  
Nahashon Osinde ◽  
Japheth Ka’pesha Odira ◽  
Patrick Kariuki Wanjiru ◽  
Margaret Wanjiku Mwangi
Keyword(s):  
Shape Memory ◽  
Recovery Rate ◽  
Shape Recovery ◽  
Shape Memory Polymer ◽  
Print Quality ◽  
Stimuli Responsive ◽  
4D Printing ◽  
Printing Parameters ◽  
Made In

Shape Memory Polymer (SMP) is stimuli-responsive material with the ability to recover the original shape from a deformation upon triggering by an appropriate stimulus like heat, light, and electricity. The shape recovery properties can be harnessed through 4D printing of self-recoverable functional structures and made usable in fields like medicine and robotics. To investigate the recovery properties, best printing parameters and optimal sizes, 4D reconfigurable gripper designed in CAD was printed in Ultimaker 2 Printer. Different stencils were made in varying printing parameters of temperature, infill, speed and time. Analysis for the stencils proved best print quality at a temperature of 195 °C and nozzle retract speed of 40mm/s. Shape recovery characterization was done on MATLAB. A printing temperature of 203 °C, infill density of 38% and printing speed of 40 mm/s gave the gripper with the best print quality. Characterization of the varying performances of the four grippers was attributed to the different infill percentages. The lower the infill, the higher the recovery rate due to the low stiffness of the gripper. The best recovery rate of 96.93% was associated with an optimal printing temperature of 203 °C.

Effects of ionic liquid types on the tribological, mechanical, and thermal properties of ionic liquid modified graphene/polyimide shape memory composites

2021 ◽  
pp. 095400832199676
Author(s):  
Yuting Ouyang ◽  
Qiu Zhang ◽  
Xiukun Liu ◽  
Ruan Hong ◽  
Xu Xu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ionic Liquid ◽  
Composite Materials ◽  
Shape Memory ◽  
Recovery Rate ◽  
Shape Recovery ◽  
Graphene Nanosheets ◽  
Mechanical And Thermal Properties ◽  
Thermal And Mechanical Properties ◽  
Modified Graphene

Different ionic liquid modified graphene nanosheets (IG) were induced into polyimide (PI) to improve the tribological, thermal, and mechanical properties of shape memory IG/PI composites. The results demonstrated that when using 1-aminoethyl-3-methylimidazole bromide to modify graphene nanosheets (IG-1), the laser-driven shape recovery rate of IG-1/PI composites (IGPI-1) reached 73.02%, which was 49.36% higher than that of pure PI. In addition, the IGPI-1 composite materials reached the maximum shape recovery rate within 15 s. Additionally, under dry sliding, the addition of IG can significantly improve the tribological properties of composite materials. IGPI-1 exhibited the best self-lubricating properties. Compared with pure PI, the friction coefficient (0.19) and wear rate (2.62 × 10–5) mm3/Nm) were reduced by 44.1% and 24.2%, respectively, and the T10% of IGPI-1 increased by 32.2°C. The Tg of IGPI-1 reached 256.5°C, which was 8.4°C higher than that of pure PI. In addition, the tensile strength and modulus of IGPI-1 reached 82.3 MPa and 1.18 GPa, which were significantly increased by 33.6% and 29.8%, respectively, compared with pure PI. We hope that this work will be helpful for the preparation of shape memory materials with excellent tribological, thermal, and mechanical properties.

scholarly journals Effect of Nanopores on Mechanical Properties of the Shape Memory Alloy

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 529
Author(s):  
Chunzhi Du ◽  
Zhifan Li ◽  
Bingfei Liu
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Shape Memory ◽  
Young’S Modulus ◽  
Residual Strain ◽  
Surface Effect ◽  
Young's Modulus ◽  
Strain Curve ◽  
Stress Strain ◽  
Strength Limit

Nanoporous Shape Memory Alloys (SMA) are widely used in aerospace, military industry, medical and health and other fields. More and more attention has been paid to its mechanical properties. In particular, when the size of the pores is reduced to the nanometer level, the effect of the surface effect of the nanoporous material on the mechanical properties of the SMA will increase sharply, and the residual strain of the SMA material will change with the nanoporosity. In this work, the expression of Young’s modulus of nanopore SMA considering surface effects is first derived, which is a function of nanoporosity and nanopore size. Based on the obtained Young’s modulus, a constitutive model of nanoporous SMA considering residual strain is established. Then, the stress–strain curve of dense SMA based on the new constitutive model is drawn by numerical method. The results are in good agreement with the simulation results in the published literature. Finally, the stress-strain curves of SMA with different nanoporosities are drawn, and it is concluded that the Young’s modulus and strength limit decrease with the increase of nanoporosity.

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).

Design of Shape Memory Alloy Springs With Applications in Vibration Control

1993 ◽  
Vol 115 (1) ◽  
pp. 129-135 ◽  
Author(s):  
C. Liang ◽  
C. A. Rogers
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Vibration Control ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Design Method ◽  
Control Area ◽  
Spring Constant ◽  
Damping Capacity

Shape memory alloys (SMAs) have several unique characteristics, including their Young’s modulus-temperature relations, shape memory effects, and damping characteristics. The Young’s modulus of the high-temperature austenite of SMAs is about three to four times as large as that of low-temperature martensite. Therefore, a spring made of shape memory alloy can change its spring constant by a factor of three to four. Since a shape memory alloy spring can vary its spring constant, provide recovery stress (shape memory effect), or be designed with a high damping capacity, it may be useful in adaptive vibration control. Some vibration control concepts utilizing the unique characteristics of SMAs will be presented in this paper. Shape memory alloy springs have been used as actuators in many applications although their use in the vibration control area is very recent. Since shape memory alloys differ from conventional alloy materials in many ways, the traditional design approach for springs is not completely suitable for designing SMA springs. Some design approaches based upon linear theory have been proposed for shape memory alloy springs. A more accurate design method for SMA springs based on a new nonlinear thermomechanical constitutive relation of SMA is also presented in this paper.

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