Memory characteristics studies for large deflections in amorphous polymers: Experiments and numerical simulation:
01 May 2016-Journal of Intelligent Material Systems and Structures (SAGE Publications)-Vol. 27, Iss: 9, pp 1203-1217
TL;DR: In this article, the shape memory behavior for large deflections in a ring-shaped epoxy-based shape memory polymer specimen is studied and a thermo-mechanical test setup was built to study the memory characteristics of ring shaped specimens with three different ratios of epoxy resin and hardener.
Abstract: In this work, the shape memory behaviour for large deflections in a ring-shaped epoxy-based shape memory polymer specimen is studied. A thermo-mechanical test setup was built to study the memory characteristics of ring shaped specimens with three different ratios of epoxy resin and hardener. Thermo-mechanical characterizations were also carried out to understand the material behaviour during shape fixing and recovery phases and also to obtain the material parameters for numerical simulations. Numerical simulations are carried out using a model proposed earlier by the authors based on the theory of multiple natural configurations and implemented using the VUMAT feature of ABAQUS commercial software. The simulation results for free shape recovery and constraint load recovery for large deflections confirm that the model performs well especially in relation to the memory dependent characteristics.
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TL;DR: In this paper, vapor-grown carbon nanofiber/poly(ethylene-co-vinyl acetate) nanocomposites were systematically and explicitly investigated through combined analytical techniques.
Abstract: Vapor-grown carbon nanofibers were filled into poly(ethylene-co-vinyl acetate) through solution mixing to achieve electrical-active two-way shape memory. The vapor-grown carbon nanofiber/poly(ethylene-co-vinyl acetate) nanocomposites were systematically and explicitly investigated through combined analytical techniques. Experimental results showed an increase in crystallization temperature (Tc) and a decrease in melting temperature (Tm) as the vapor-grown carbon nanofiber concentration in the nanocomposites increased. This result indicates that carbon nanofibers can act as nucleating agents during crystallization but may hinder the formation of thermodynamically stable crystals. The nanocomposites had a higher modulus but a lower strength than pure poly(ethylene-co-vinyl acetate). In two-way shape memory testing, a decrease in reversible strain and shape recovery occurred in the nanocomposites. Nevertheless, obvious two-way shape switching was observed in all samples during cyclic heating and cooling. The...
25 citations
Cites background from "Memory characteristics studies for ..."
...…external stimuli have elicited much interest because they may play an important role in smart actuators, novel sensors, biomedical devices, and aerospace structures (Luo et al., 2015; Santo, 2016; Sujithra et al., 2016; Tan et al., 2015; Tippets et al., 2015; Yao et al., 2016a; Zhou et al., 2014)....
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TL;DR: In this paper, the effect of sequence of shape setting on the shape recovery response for an epoxy-based amorphous SMP was studied and the shape memory cycle for coupled axial-twist deformations was also simulated in ABAQUS-VUMAT.
12 citations
TL;DR: In this article , a constitutive model was constructed to describe the changes in mechanical properties of amorphous polymers from below to above glass transition temperature (θg), in which an exponential evolution equation of volume fraction was constructed.
4 citations
Journal Article•
TL;DR: In the paper, the shape memory mechanism of shape memory polymers is analyzed and some disadvantages in the development of shapeMemory polymers are put forward and some suggestions are given.
Abstract: Shape memory polymers can response to the external stimulation such as heat,chemicals,mechanism,light,magnetism,electricity and so on,to change their technical parametersAs a type of important functional materials,shape memory polymers have undergone a rapid development since 1980 s,which are widely applied in the fields of aerospace,medicine,power electronies,packaging and intelligent control systemIn the paper,the shape memory mechanism of shape memory polymers is analyzedSome common shape memory polymers and their applications in all fields are described in details,respectivelyAt last,some disadvantages in the development of shape memory polymers are put forward and some suggestions are given
3 citations
TL;DR: In this paper, the shape recovery response of different epoxy polymer and its SiC composites with rectangular shaped samples was investigated, and the results showed that SiC dispersed epoxy with TETA hardener gives the highest shape fixity.
1 citations
References
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TL;DR: A very broad, additional spectrum of possible applications for intelligent polymers that covers an area from minimally invasive surgery, through high-performance textiles, up to self-repairing plastic components in every kind of transportation vehicles.
Abstract: Shape memory polymer compositions, articles of manufacture thereof, and methods of preparation and use thereof are described. The shape memory polymer compositions can hold more than one shape in memory. Suitable compositions include at least one hard segment and at least one soft segment. The Ttrans of the hard segment is preferably between -30 and 270 °C. At least one of the hard or soft segments can contain a cross-linkable group, and the segments can be linked by formation of an interpenetrating network or a semi-interpenetrating network, or by physical interactions of the blocks. Objects can be formed into a given shape at a temperature above the Ttrans of the hard segment, and cooled to a temperature below the Ttrans of the soft segment. If the object is subsequently formed into a second shape, the object can return to its original shape by heating the object above the Ttrans of the soft segment and below the Ttrans of the hard segment. The compositions can also include two soft segments which are linked via functional groups which are cleaved in response to application of light, electric field, magnetic field or ultrasound. The cleavage of these groups causes the object to return to its original shape.
2,837 citations
TL;DR: It is discussed how the described shape-memory polymers show great potential for diverse applications, including in the medical arena, sensors, and actuators, and as dictated by macromolecular details.
Abstract: Shape-memory polymers (SMPs) have attracted significant attention from both industrial and academic researchers due to their useful and fascinating functionality. This review thoroughly examines progress in shape-memory polymers, including the very recent past, achieved by numerous groups around the world and our own research group. Considering all of the shape-memory polymers reviewed, we identify a classification scheme wherein nearly all SMPs may be associated with one of four classes in accordance with their shape fixing and recovering mechanisms and as dictated by macromolecular details. We discuss how the described shape-memory polymers show great potential for diverse applications, including in the medical arena, sensors, and actuators.
1,805 citations
"Memory characteristics studies for ..." refers background or methods in this paper
...Also, this amorphous cross-link thermoset glassy polymer is reported to have excellent shape recovery characteristics and no molecular slippage occurs between the chains due to chemical cross-linking (Liu et al., 2007; Rousseau, 2008)....
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...The shape fixity and shape recovery ratio is calculated for all epoxy ratios compared in Table 2 as given by Liu et al. (2007)....
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TL;DR: Shape-memory polymers as discussed by the authors are an emerging class of active polymers that can change their shape in a predefined way from shape A to shape B when exposed to an appropriate stimulus.
1,575 citations
TL;DR: Shape-memory polymers (SMPs) undergo significant macroscopic deformation upon the application of an external stimulus (e.g., heat, electricity, light, magnetism, moisture and even a change in pH value).
1,217 citations
"Memory characteristics studies for ..." refers methods in this paper
...Extensive reviews on SMP stimulus methods, functionality with applications are described by Leng et al. (2011) and Meng and Li (2013)....
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TL;DR: It is shown that the perfluorosulphonic acid ionomer (PFSA), which has only one broad reversible phase transition, exhibits dual-, triple-, and at least quadruple-shape memory effects, all highly tunable without any change to the material composition.
Abstract: Shape memory polymers are materials that can memorize temporary shapes and revert to their permanent shape upon exposure to an external stimulus such as heat, light, moisture or magnetic field. Such properties have enabled a variety of applications including deployable space structures, biomedical devices, adaptive optical devices, smart dry adhesives and fasteners. The ultimate potential for a shape memory polymer, however, is limited by the number of temporary shapes it can memorize in each shape memory cycle and the ability to tune the shape memory transition temperature(s) for the targeted applications. Currently known shape memory polymers are capable of memorizing one or two temporary shapes, corresponding to dual- and triple-shape memory effects (also counting the permanent shape), respectively. At the molecular level, the maximum number of temporary shapes a shape memory polymer can memorize correlates directly to the number of discrete reversible phase transitions (shape memory transitions) in the polymer. Intuitively, one might deduce that multi-shape memory effects are achievable simply by introducing additional reversible phase transitions. The task of synthesizing a polymer with more than two distinctive and strongly bonded reversible phases, however, is extremely challenging. Tuning shape memory effects, on the other hand, is often achieved through tailoring the shape memory transition temperatures, which requires alteration in the material composition. Here I show that the perfluorosulphonic acid ionomer (PFSA), which has only one broad reversible phase transition, exhibits dual-, triple-, and at least quadruple-shape memory effects, all highly tunable without any change to the material composition.
1,162 citations
"Memory characteristics studies for ..." refers background in this paper
..., 2010) or a multi-shape memory effect with a single broad transition temperature (Xie, 2010)....
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...It is reported in the literature that the shape memory cycle time will be shortened for materials with lower rubbery to glassy modulus (Er / Eg) and higher tand peak (Rousseau and Xie, 2010)....
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...In addition, SMPs are not only limited to dual shape memory effect, but also triple shape memory effect with two reversible phases (Zotzmann et al., 2010) or a multi-shape memory effect with a single broad transition temperature (Xie, 2010)....
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...Rousseau and Xie (2010) reported that the shape memory performance is strongly influenced by the strain-dependent thermal expansion/contraction during shape memory cycle....
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