Design of Multistimuli-Responsive Shape-Memory Polymer Materials by Reactive Extrusion

2014 ◽  
Vol 26 (20) ◽  
pp. 5860-5867 ◽  
Author(s):  
Florence Pilate ◽  
Rosica Mincheva ◽  
Julien De Winter ◽  
Pascal Gerbaux ◽  
Linbo Wu ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Reactive Extrusion ◽  
Polymer Materials

Characterizations of Silicon Carbide Whisker-Filled in Benzoxazine-Epoxy Shape Memory Polymers

2015 ◽  
Vol 659 ◽  
pp. 373-377 ◽  
Author(s):  
Chutiwat Likitaporn ◽  
Sarawut Rimdusit
Keyword(s):  
Silicon Carbide ◽  
Shape Memory ◽  
Polymer Composites ◽  
Binary Systems ◽  
Glassy State ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Polymer Materials ◽  
External Stimulation ◽  
Silicon Carbide Whisker

Shape memory polymers (SMPs) are polymer materials that can fix the temporary shape and then recover to their original permanent shape by external stimulation, i.e. applied heat. In this research, shape memory polymer composites (SMPCs) from benzoxazine (BA-a)-epoxy binary systems reinforced with adamantine silicon carbide whisker (SiCw) are investigated. The SiCw contents are controlled to be in range of 0 to 15% by weight. All specimens were fabricated by compression molding technique. The results revealed that the shape memory polymer composites showed higher glassy state storage modulus with increasing amount of the whisker suggesting substantial reinforcement effect of the whisker used. The glass transition temperature (Tg) was also improved from 102°C of the based polymer to the value about 122°C with the addition of about 15% by weight of the silicon carbide whisker. Finally, shape recovery stress systematically increased from the value about 1.5MPa of the unfilled polymer matrix to the value about 3.2MPa with an addition of 15% by weight of the silicon carbide whisker. The positive effect on thermal stability from SiCw addition is expected from the modification and will be reported in this work.

scholarly journals Non-woven shape-memory polymer blend actuators

MRS Advances ◽  
2021 ◽  
Author(s):  
Victor Izraylit ◽  
Matthias Heuchel ◽  
Karl Kratz ◽  
Andreas Lendlein
Keyword(s):  
Shape Memory ◽  
Bulk Material ◽  
Shape Memory Polymer ◽  
Polymer Materials ◽  
Design Approach ◽  
Structural Performance ◽  
Hierarchical Design ◽  
Soft Actuator ◽  
Processing Techniques ◽  
Effective Design

Abstract The hierarchical design approach provides various opportunities to adjust the structural performance of polymer materials. Electrospinning processing techniques give access to molecular orientation as a design parameter, which we consider here in view of the shape-memory actuation performance. The aim of this work is to investigate how the reversible strain $$\varepsilon^{\prime}_{{{\text{rev}}}}$$ ε rev ′ can be affected by a morphology change from a bulk material to an electrospun mesh. $$\varepsilon^{\prime}_{{{\text{rev}}}}$$ ε rev ′ could be increased from 5.5 ± 0.5% to 15 ± 1.8% for a blend from a multiblock copolymer with poly(ε-caprolactone) (PCL) and poly(L-lactide) (PLLA) segments with oligo(D-lactide) (ODLA). This study demonstrates an effective design approach for enhancing soft actuator performance, which can be broadly applied in soft robotics and medicine. Graphic abstract

scholarly journals Chronic Intracortical Recording and Electrochemical Stability of Thiol-ene/Acrylate Shape Memory Polymer Electrode Arrays

Micromachines ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 500 ◽  
Author(s):  
Allison Stiller ◽  
Joshua Usoro ◽  
Christopher Frewin ◽  
Vindhya Danda ◽  
Melanie Ecker ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Polymer Materials ◽  
Clinical Implementation ◽  
Electrode Arrays ◽  
Neuroinflammatory Response ◽  
Order Of Magnitude ◽  
Intracortical Electrodes ◽  
Glial Scarring ◽  
Implanted Devices

Current intracortical probe technology is limited in clinical implementation due to the short functional lifetime of implanted devices. Devices often fail several months to years post-implantation, likely due to the chronic immune response characterized by glial scarring and neuronal dieback. It has been demonstrated that this neuroinflammatory response is influenced by the mechanical mismatch between stiff devices and the soft brain tissue, spurring interest in the use of softer polymer materials for probe encapsulation. Here, we demonstrate stable recordings and electrochemical properties obtained from fully encapsulated shape memory polymer (SMP) intracortical electrodes implanted in the rat motor cortex for 13 weeks. SMPs are a class of material that exhibit modulus changes when exposed to specific conditions. The formulation used in these devices softens by an order of magnitude after implantation compared to its dry, room-temperature modulus of ~2 GPa.

A Thermo-Mechanical Constitutive Model of Glassy Shape Memory Polymers

2016 ◽  
Vol 853 ◽  
pp. 96-100 ◽  
Author(s):  
Jian Li ◽  
Shi Yu Dong ◽  
Qian Hua Kan ◽  
Guo Zheng Kang ◽  
Wen Yi Yan
Keyword(s):  
Constitutive Model ◽  
Shape Memory ◽  
Evolution Equations ◽  
Model Simulation ◽  
Shape Memory Polymer ◽  
Three Dimensional ◽  
Shape Memory Polymers ◽  
Nonlinear Evolution Equations ◽  
Polymer Materials ◽  
Extended Model

Glassy shape memory polymer materials are applied successfully in biomedical fields due to their large recovery deformation, excellent biocompatibility and unique biodegradability. To predict the thermo-mechanical behavior of glassy shape memory polymers in biomedical devices accurately, a reasonably three-dimensional thermo-mechanical constitutive model must be established firstly. A one-dimensional linear-elastic constitutive model proposed by Tobushi et. al. (1997) was extended to capture the loading level dependent degradation of shape memory effect by introducing new nonlinear evolution equations with threshold values. Comparisons between experiments and simulations were carried to validate the extended model. Simulation results agree with experiments well, especially for the high loading levels.

scholarly journals Design of Shape Memory Thermoplastic Material Systems for FDM-Type Additive Manufacturing

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4254
Author(s):  
Paulina A. Quiñonez ◽  
Leticia Ugarte-Sanchez ◽  
Diego Bermudez ◽  
Paulina Chinolla ◽  
Rhyan Dueck ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Shape Memory ◽  
Thermomechanical Processing ◽  
Material Selection ◽  
Shape Memory Polymer ◽  
Fused Filament Fabrication ◽  
Materials Development ◽  
Thermoplastic Material ◽  
Polymer Systems ◽  
Injection Molded

The work presented here describes a paradigm for the design of materials for additive manufacturing platforms based on taking advantage of unique physical properties imparted upon the material by the fabrication process. We sought to further investigate past work with binary shape memory polymer blends, which indicated that phase texturization caused by the fused filament fabrication (FFF) process enhanced shape memory properties. In this work, two multi-constituent shape memory polymer systems were developed where the miscibility parameter was the guide in material selection. A comparison with injection molded specimens was also carried out to further investigate the ability of the FFF process to enable enhanced shape memory characteristics as compared to other manufacturing methods. It was found that blend combinations with more closely matching miscibility parameters were more apt at yielding reliable shape memory polymer systems. However, when miscibility parameters differed, a pathway towards the creation of shape memory polymer systems capable of maintaining more than one temporary shape at a time was potentially realized. Additional aspects related to impact modifying of rigid thermoplastics as well as thermomechanical processing on induced crystallinity are also explored. Overall, this work serves as another example in the advancement of additive manufacturing via materials development.

Autonomous Off‐Equilibrium Morphing Pathways of a Supramolecular Shape‐Memory Polymer

2021 ◽  
pp. 2102473
Author(s):  
Wenjun Peng ◽  
Guogao Zhang ◽  
Qian Zhao ◽  
Tao Xie
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer

scholarly journals Pressure Orientation-Dependent Recovery of 3D-Printed PLA Objects with Varying Infill Degree

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1275 ◽  
Author(s):  
Guido Ehrmann ◽  
Andrea Ehrmann
Keyword(s):  
Shape Memory ◽  
Fused Deposition Modeling ◽  
Static Load ◽  
Shape Memory Polymer ◽  
Applied Pressure ◽  
Poly Lactic Acid ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Load Tests ◽  
3D Printed

Poly(lactic acid) is not only one of the most often used materials for 3D printing via fused deposition modeling (FDM), but also a shape-memory polymer. This means that objects printed from PLA can, to a certain extent, be deformed and regenerate their original shape automatically when they are heated to a moderate temperature of about 60–100 °C. It is important to note that pure PLA cannot restore broken bonds, so that it is necessary to find structures which can take up large forces by deformation without full breaks. Here we report on the continuation of previous tests on 3D-printed cubes with different infill patterns and degrees, now investigating the influence of the orientation of the applied pressure on the recovery properties. We find that for the applied gyroid pattern, indentation on the front parallel to the layers gives the worst recovery due to nearly full layer separation, while indentation on the front perpendicular to the layers or diagonal gives significantly better results. Pressing from the top, either diagonal or parallel to an edge, interestingly leads to a different residual strain than pressing from front, with indentation on top always firstly leading to an expansion towards the indenter after the first few quasi-static load tests. To quantitatively evaluate these results, new measures are suggested which could be adopted by other groups working on shape-memory polymers.

scholarly journals Harnessing reversible dry adhesion using shape memory polymer microparticles

RSC Advances ◽  
2021 ◽  
Vol 11 (32) ◽  
pp. 19616-19622
Author(s):  
Wenbing Li ◽  
Junhao Liu ◽  
Wanting Wei ◽  
Kun Qian
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Memory Effects ◽  
Reversible Adhesion ◽  
Dry Adhesion ◽  
Bonding Property ◽  
Shape Memory Effects ◽  
Polymer Microparticles

Shape memory polymers can provide excellent bonding property because of their shape memory effects. This paper proposes an adhesive unit that is capable of repeatable smart adhesion and exhibits reversible adhesion under heating.

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