Different Processing Methods to Obtain Porous Structure in Shape Memory Polymers

2007 ◽  
Vol 539-543 ◽  
pp. 663-668 ◽  
Author(s):  
Silvia Farè ◽  
Luigi de Nardo ◽  
S. De Cicco ◽  
M. Jovenitti ◽  
Maria Cristina Tanzi

In the last few years, clinical procedures undergone huge modifications. Among them, mini-invasive surgery has modified the clinical practice and the quality of life of patients. Shape Memory Polymers (SMPs), a class of stimuli-responsive materials, can be considered ideal candidates for the design of devices for mini-invasive surgical procedures. Such a device can be inserted in a packed in, temporary shape and later can expand at body temperature. A bone defect could be filled by a SMP porous structure, that improves the tissue integration and healing. In this work, two different processing techniques to obtain porous shape memory polymer scaffolds from Calo MER™ and MM-4520, two SMPs, are presented. Porous structures were obtained by micro-extrusion with different chemical foaming agents or with sodium chloride, or by solvent casting/particulate leaching. The morphology, the thermo-mechanical and the shape recovery properties of the SMP porous samples were investigated. Tridimensional porous structures showed a well interconnected morphology, with a pore size in the range aimed for bone interaction applications. The shape memory properties were not significantly affected by the transformation processes: a good ability of recovering the original shape was verified. Therefore, the porous structures, obtained from these SMP materials, appear adequate for an use as bone filler.

Author(s):  
Luigi de Nardo ◽  
Sabrina De Cicco ◽  
Matteo Jovenitti ◽  
Maria C. Tanzi ◽  
Silvia Fare`

In the recent past, clinical procedures underwent huge modifications. Among them, mini-invasive surgery has modified the clinical practice and the quality of life of patients. All these evolutions are strictly correlated to the advancement in materials science. Shape Memory Polymers (SMPs), a novel class of stimuli-responsive materials, can be considered ideal candidates for the design of devices for mini-invasive surgery. Such devices can be inserted in a compact temporary shape and subsequently expanded at body temperature: a bone defect, e.g., could be filled by a filler made of SMPs. With the aim of promoting tissue integration and healing, these structures should present a suitable porosity. In this work two different processing techniques to obtain shape memory polymer scaffolds from Calo·MER™, a SMP, are presented. Porous structures were obtained by micro-extrusion, with different chemical expanding agents or by particulate leaching with salt. Morphology, thermo-mechanical and shape recovery properties of the SMP porous samples were investigated. The obtained foams show a well interconnected morphology, with a pore size in the range suitable for bone applications. Shape memory properties were not significantly affected by the transformation processes: a good ability of recovering the original shape was verified. Therefore, foams obtained from these materials could be used to fabricate devices for mini-invasive surgical procedures.


2020 ◽  
Vol 64 (4) ◽  
pp. 425-442
Author(s):  
Mathew J. Haskew ◽  
John G. Hardy

Shape-memory polymers (SMPs) enable the production of stimuli-responsive polymer-based materials with the ability to undergo a large recoverable deformation upon the application of an external stimulus. Academic and industrial research interest in the shape-memory effects (SMEs) of these SMP-based materials is growing for task-specific applications. This mini-review covers interesting aspects of SMP-based materials, their properties, how they may be investigated and highlights examples of the potential applications of these materials.


2008 ◽  
Author(s):  
Bernhard Hiebl ◽  
Dorothee Rickert ◽  
Rosemarie Fuhrmann ◽  
Friedrich Jung ◽  
Andres Lendlein ◽  
...  

RSC Advances ◽  
2021 ◽  
Vol 11 (32) ◽  
pp. 19616-19622
Author(s):  
Wenbing Li ◽  
Junhao Liu ◽  
Wanting Wei ◽  
Kun Qian

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.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wang Zhang ◽  
Hao Wang ◽  
Hongtao Wang ◽  
John You En Chan ◽  
Hailong Liu ◽  
...  

AbstractFour-dimensional (4D) printing of shape memory polymer (SMP) imparts time responsive properties to 3D structures. Here, we explore 4D printing of a SMP in the submicron length scale, extending its applications to nanophononics. We report a new SMP photoresist based on Vero Clear achieving print features at a resolution of ~300 nm half pitch using two-photon polymerization lithography (TPL). Prints consisting of grids with size-tunable multi-colours enabled the study of shape memory effects to achieve large visual shifts through nanoscale structure deformation. As the nanostructures are flattened, the colours and printed information become invisible. Remarkably, the shape memory effect recovers the original surface morphology of the nanostructures along with its structural colour within seconds of heating above its glass transition temperature. The high-resolution printing and excellent reversibility in both microtopography and optical properties promises a platform for temperature-sensitive labels, information hiding for anti-counterfeiting, and tunable photonic devices.


2016 ◽  
Vol 2 (1) ◽  
pp. e1501297 ◽  
Author(s):  
Qian Zhao ◽  
Weike Zou ◽  
Yingwu Luo ◽  
Tao Xie

Stimuli-responsive materials with sophisticated yet controllable shape-changing behaviors are highly desirable for real-world device applications. Among various shape-changing materials, the elastic nature of shape memory polymers allows fixation of temporary shapes that can recover on demand, whereas polymers with exchangeable bonds can undergo permanent shape change via plasticity. We integrate the elasticity and plasticity into a single polymer network. Rational molecular design allows these two opposite behaviors to be realized at different temperature ranges without any overlap. By exploring the cumulative nature of the plasticity, we demonstrate easy manipulation of highly complex shapes that is otherwise extremely challenging. The dynamic shape-changing behavior paves a new way for fabricating geometrically complex multifunctional devices.


2020 ◽  
Vol 11 (7) ◽  
pp. 1369-1374 ◽  
Author(s):  
Wusha Miao ◽  
Weike Zou ◽  
Yingwu Luo ◽  
Ning Zheng ◽  
Qiao Zhao ◽  
...  

Polycaprolactone based thermadapt shape memory polymers with precisely controlled structures allow tunable shape reconfigurability.


Author(s):  
Silvia Farè ◽  
Luigi De Nardo ◽  
S. De Cicco ◽  
M. Jovenitti ◽  
Maria Cristina Tanzi

Author(s):  
L. Santo ◽  
L. Iorio ◽  
G. M. Tedde ◽  
F. Quadrini

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.


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