3D printed self-expandable vascular stents from biodegradable shape memory polymer

2018 ◽  
Vol 37 (8) ◽  
pp. 3222-3228 ◽  
Author(s):  
Han Jia ◽  
Shu-Ying Gu ◽  
Kun Chang
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Vascular Stents ◽  
3D Printed

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.

3D printed biodegradable functional temperature-stimuli shape memory polymer for customized scaffoldings

2020 ◽  
Vol 108 ◽  
pp. 103781 ◽  
Author(s):  
Akash Pandey ◽  
Gurminder Singh ◽  
Sunpreet Singh ◽  
Kanishak Jha ◽  
Chander Prakash
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
3D Printed

scholarly journals 3D Printed Shape Memory Polymers Produced via Direct Pellet Extrusion

Micromachines ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 87
Author(s):  
Trenton Cersoli ◽  
Alexis Cresanto ◽  
Callan Herberger ◽  
Eric MacDonald ◽  
Pedro Cortes
Keyword(s):  
3D Printing ◽  
Shape Memory ◽  
Memory Performance ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Qr Code ◽  
Thermal Stimulus ◽  
Conventional Film ◽  
3D Printed ◽  
Smart Actuator

Shape memory polymers (SMPs) are materials capable of changing their structural configuration from a fixed shape to a temporary shape, and vice versa when subjected to a thermal stimulus. The present work has investigated the 3D printing process of a shape memory polymer (SMP)-based polyurethane using a material extrusion technology. Here, SMP pellets were fed into a printing unit, and actuating coupons were manufactured. In contrast to the conventional film-casting manufacturing processes of SMPs, the use of 3D printing allows the production of complex parts for smart electronics and morphing structures. In the present work, the memory performance of the actuating structure was investigated, and their fundamental recovery and mechanical properties were characterized. The preliminary results show that the assembled structures were able to recover their original conformation following a thermal input. The printed parts were also stamped with a QR code on the surface to include an unclonable pattern for addressing counterfeit features. The stamped coupons were subjected to a deformation-recovery shape process, and it was observed that the QR code was recognized after the parts returned to their original shape. The combination of shape memory effect with authentication features allows for a new dimension of counterfeit thwarting. The 3D-printed SMP parts in this work were also combined with shape memory alloys to create a smart actuator to act as a two-way switch to control data collection of a microcontroller.

scholarly journals Structure and Compatibility Study of Modified Polyurethane/Fe3O4 Nanocomposite for Shape Memory Materials

2015 ◽  
Vol 15 (2) ◽  
pp. 130-140 ◽  
Author(s):  
Dick Ferieno Firdaus ◽  
Masrudin Masrudin ◽  
Dessy Ayu Lestari ◽  
Mutya Rahmah Arbi ◽  
Mochamad Chalid
Keyword(s):  
Shape Memory ◽  
Smart Materials ◽  
Molecular Design ◽  
Soft Segment ◽  
Shape Memory Polymer ◽  
Transient State ◽  
Polymer Chains ◽  
Nano Particles ◽  
Compatibility Study ◽  
Vascular Stents

Shape Memory Polymer (SMP) is one of smart materials class that has the ability to recall a given shape before deformation in the transient state. The development of SMP is dominated by polyurethane which is currently focused on the optimization of manufacturing-related research (ease of processing), and the extraction of the potential for biomedical applications. In this study, Shape Memory Polyurethane (SMPU) with Polyethylene Glycol-based material (PEG mw: 6000) as soft segment, 4,4'-Methylenebis (Cyclohexyl isocyanate) (HMDI) as a hard segment and 1,1,1-Trimethylol propane (TMP) as a chain extender were used as a candidate for Vascular Stents. Materials used for the fillers were nano particles of magnetite (Fe3O4) which have 20–50 nm diameters. Variations of the composition were used as a variable. Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) were conducted to investigate the polymer chains which were formed during polymerization, Field Emission Scanning Electron Microscopy (FE-SEM) was used to analyze the interface between the filler and the composite matrix. Manual physical actuation was conducted to analyze the physical recovery and transition temperature of the SMPU. Composition and fillers effect on the performance of SMPU composite were discussed in detail along with analysis of its structure and molecular design.

Frontally polymerizable shape memory polymer for 3D printing of free-standing structures

2021 ◽  
Author(s):  
Yongsan An ◽  
Joon Hyeok Jang ◽  
Ji Ho Youk ◽  
Woong-Ryeol Yu
Keyword(s):  
Shape Memory ◽  
Memory Performance ◽  
Shape Memory Polymer ◽  
Three Dimensional ◽  
Frontal Polymerization ◽  
4D Printing ◽  
Free Standing ◽  
Time Shape ◽  
Standing Structure ◽  
3D Printed

Abstract Four-dimensional (4D) printing is used to describe three-dimensional (3D)-printed objects with properties that change over time. Shape memory polymers (SMPs) are representative materials for 4D printing technologies. The ability to print geometrically complex, free-standing forms with SMPs is crucial for successful 4D printing. In this study, an SMP capable of frontal polymerization featuring exothermic self-propagation was synthesized by adding cyclooctene to a poly(dicyclopentadiene) network, resulting in switching segments. The rheological properties of this SMP were controlled by adjusting incubation time. A nozzle system was designed such that the SMP could be printed with simultaneous polymerization to yield a free-standing structure. The printing speed was set to 3 cm/min according to the frontal polymerization speed. A free-standing, hexagonal spiral was successfully printed and printed spiral structure showed excellent shape memory performance with a fixity ratio of about 98% and a recovery ratio of 100%, thereby demonstrating the 3D printability and shape memory performance of frontally polymerizable SMPs.

Deformation Properties of 3D Printed Shape Memory Polymer

2016 ◽  
Vol 725 ◽  
pp. 378-382 ◽  
Author(s):  
Kohei Takeda ◽  
Shunichi Hayashi ◽  
Kazunori Ueki
Keyword(s):  
Transition Temperature ◽  
Shape Memory ◽  
Shape Memory Polymer ◽  
3D Printer ◽  
New Device ◽  
Fused Deposition ◽  
Deformation Properties ◽  
3D Printed ◽  
The Individual ◽  
Short Time

Recently, the 3D printer which can make products in a short time without cutting or casting has been attracted worldwide attention. If we use the 3D printer, it is possible that a customized product which is well suited to the individual is fabricated with low cost and in a short time. On the other hand, in the intelligent materials, shape memory polymer (SMP) has been practically used. In SMP, shape fixity and shape recovery appear based on the difference of properties of molecular motion between above and below the glass transition temperature in temperature variation. The thermomechanical property of SMP is close to that of the human body around glass the transition temperature. Since SMP has these characteristics, it can be applied to the elements coming into contact with body as a nursing-care robot in the medical field. Hence, if we make a product with SMP using the 3D printer, the new device which is well suited to the individual can be developed. In the present paper, the deformation properties of SMP made by the fused deposition modeling (FDM) 3D printer were investigated. The results obtained are as follows. (1) The deformation resistance and recovery strain in unloading of the 3D printed SMP under a low printing rate are higher and larger than these of the high printing rate. (2) If we heat the 3D printed SMP under a high printing rate, it does not recover the original shape perfectly since the residual stress appears during printing.

scholarly journals Lightweight Microlattice With Tunable Mechanical Properties Using 3D Printed Shape Memory Polymer

2018 ◽  
Author(s):  
Chen Yang ◽  
Manish Boorugu ◽  
Andrew Dopp ◽  
Howon Lee
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Shape Memory ◽  
Shape Memory Polymer ◽  
Three Dimensional ◽  
Temperature Shift ◽  
Spatial Arrangement ◽  
Mechanical Metamaterials ◽  
3D Printed ◽  
Varying Environments

Metamaterials are architected artificial materials engineered to exhibit properties not typically found in natural materials. Increasing attention has recently been given to mechanical metamaterials with unprecedented mechanical properties including high stiffness, strength, or/and resilience even at extremely low density. These unusual mechanical performances emerge from the three-dimensional (3D) spatial arrangement of the micro-structural elements designed to effectively distribute mechanical loads. Recent advances in additive manufacturing in micro-/nano-scale have catalyzed the growing interest in this field. This work presents a new lightweight microlattice with tunable and recoverable mechanical properties using a three-dimensionally architected shape memory polymer (SMP). SMP microlattices were fabricated utilizing our micro additive manufacturing technique called projection micro-stereolithography (PμSL), which uses a digital micro-mirror device (DMD™) as a dynamically reconfigurable photomask. We use a photo-crosslinkable and temperature-responsive SMP which can retain its large deformation until heated for spontaneous shape recovery. In addition, it exhibits remarkable elastic modulus changes during this transition. We demonstrate that mechanical responses of the micro 3D printed SMP microlattice can be reversibly tuned by temperature control. Mechanical testing result showed that stiffness of a SMP microlattice changed by two orders of magnitude by a moderate temperature shift by 60°C. Furthermore, the shape memory effect of the SMP allows for full restitution of the original shape of the microlattice upon heating even after substantial mechanical deformation. Mechanical metamaterials with lightweight, reversibly tunable properties, and shape recoverability can potentially lead to new smart structural systems that can effectively react and adapt to varying environments or unpredicted loads.

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