Two-way reversible shape memory behaviour of crosslinked poly(ε-caprolactone)

Pandini, Stefano; Passera, Simone; Messori, Massimo; Paderni, Katia; Toselli, Maurizio; Gianoncelli, Alessandra; Bontempi, Elza; Riccò, T.

doi:10.1016/j.polymer.2012.02.053

Cited by 143 publications

(138 citation statements)

References 33 publications

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“…The subsequent melting of crystalline phase triggers the shrinkage of specimen, which results in mechanical work carried out against an external force. The recent findings have shown that cross-linked semi-crystalline polymers also possess an invertible so-called two-way SME that has been observed for covalent networks on the basis of polycyclooctene/ trans-polyoctenamer (PCO/TOR) and of poly(!-caprolactone) (PCL) [22][23][24]. The physical background of two-way SME is on the one hand the anomalous elongation of a sample, which is initiated by the non-isothermal crystallization during cooling under load (at a constant force) and accompanied by an increase of storage modulus, and on the other hand the expected contraction of a sample during heating under the same load triggered by melting of the oriented crystalline phase and by release of the entropic network forces.…”

Section: Two-way Sme In Polymeric Materialsmentioning

confidence: 89%

Shape-memory behavior of cross-linked semi-crystalline polymers and their blends

Kolesov¹,

Dolynchuk²,

Radusch

2015

Express Polym. Lett.

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The aim of present mini-review is an attempt to perform the comparative description and analysis of results of our experimental investigation and of physically justified modeling of unconstrained one-way shape-memory effect (SME) and invertible twoway SME under load in crystallizable covalent polymer networks. Besides the dual SME in cross-linked homopolymers, the one-and two-way multi-shape behavior in heterogeneous networks on the basis of binary and ternary blends will be discussed. The special focus in present work is directed on the key role of phase morphology of cross-linked polymer blends varied by blend composition on the performances of multiple SM behavior. Brief overview of various types of SME in polymeric materialsIn the last decades the SME in polymeric materials was the research object of hundreds of original papers and many reviews (see for instance [1][2][3][4][5][6][7][8]). There are four main types of stimuli, which are able to trigger a shape change of polymeric materials: temperature variation, chemical reactions, light, and mechanical forces [2][3][4][5][6][7]. Correspondingly, among polymeric materials the thermo-, chemo-, photo-, and mechano-responsive material groups can be classified. In majority of publications, which consider SM behavior of polymer systems, the subject of investigation are thermo-responsive polymeric materials. According to the existence of ordered Abstract. The present study deals with thermally induced one-way and invertible two-way shape-memory effect (SME) in covalent networks on the basis of crystallizable (co)polymers and their blends and is an attempt to generalize the results of own investigation received by the authors in the last ten years. The main focus of work clearly lies on research of covalently crosslinked binary and ternary blends having two and three crystalline phases with different thermal stability, respectively. The existence of two or three crystalline phases possessing different melting and crystallization temperatures in heterogeneous polymer networks can lead to triple-shape or even quadruple-shape behavior of such networks. However, the performed investigations point to crucial effect of phase morphology of crosslinked polymer blends on multiplicity of their shapememory behavior beside the influence of blend content, crystallinity and cross-link density of blend phases as well as of processing conditions. For instance, triple-shape memory behavior in binary blends can be realized only if the continuous phase has a lower melting temperature than the dispersed phase. Cross-linked polymer blends are a facile alternative to expensive and complex synthesis of interpenetrating or block-copolymer networks used for shape memory polymers. In addition to findings of experimental investigation of SME in crystallizable covalent polymer networks, the results of modeling their shape-memory behavior on the basis of self-developed physically reasonable model have been briefly described and discussed. Thereby, good accordance between results of theory and ...

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Section: Two-way Sme In Polymeric Materialsmentioning

confidence: 89%

Shape-memory behavior of cross-linked semi-crystalline polymers and their blends

Kolesov¹,

Dolynchuk²,

Radusch

2015

Express Polym. Lett.

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“…In a companion paper the same authors [22] prepared peroxide crosslinked PCL with different molecular architectures. In this case the PCL was terminated by methacrylate and crosslinked in its melt phase.…”

Section: Chemical Networkmentioning

confidence: 99%

“…The SM cycle of a 2W-SMP is given in Figure 7. PCL-based 2W-SMPs were already produced and tested by Pandini and coworkers [21,22]. Recently, another strategy was proposed to produce 2W-SM polymers.…”

Section: Two-way Smp (2w-smp)mentioning

confidence: 99%

Biodegradable polyester-based shape memory polymers: Concepts of (supra)molecular architecturing

Karger‐Kocsis

Kéki

2014

Express Polym. Lett.

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Shape memory (SM) biodegradable polymers (SMPs) and related composites are emerging smart materials in different applications. SMPs may adopt one (dual-shape), two (triple-shape) or several (multishape) stable temporary shapes and recover their permanent shape (or other temporary shapes in case of multi-shape versions) upon the action of an external stimulus. The external stimulus may be temperature, pH, water, light irradiation, redox condition etc. In most cases, however, the SMPs are thermally activated. The 'switching' or transformation temperature (T trans ), enabling the material to return to its permanent shape, is either linked with the glass transition (T g ) or with the melting temperature (T m ).Thus, SMPs are often subdivided based on their switch types into T g -or T m -based SMPs. As reversible 'switches' other mechanisms such as liquid crystallization and related transitions, supermolecular assembly/disassembly, irradiation-induced reversible network formation, formation and disruption of a percolation network, may also serve [1]. The permanent shape is guaranteed by physical or chemical network structures. The latter may be both on molecular and supramolecular levels. Linkages of these networks are termed net points. The temporary shape is created by mechanical deformation above T trans . In some cases the deformation temperature may be below Abstract. Shape memory polymers (SMPs) are capable of memorizing one or more temporary shapes and recovering to the permanent shape upon an external stimulus that is usually heat. Biodegradable polymers are an emerging family within the SMPs. This minireview delivers an overlook on actual concepts of molecular and supramolecular architectures which are followed to tailor the shape memory (SM) properties of biodegradable polyesters. Because the underlying switching mechanisms of SM actions is either related to the glass transition (T g ) or melting temperatures (T m ), the related SMPs are classified as T g -or T m -activated ones. For fixing of the permanent shape various physical and chemical networks serve, which were also introduced and discussed. Beside of the structure developments in one-way, also those in two-way SM polyesters were considered. Adjustment of the switching temperature to that of the human body, acceleration of the shape recovery, enhancement of the recovery stress, controlled degradation, and recycling aspects were concluded as main targets for the future development of SM systems with biodegradable polyesters.

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“…Since an external force (by means of either applying an external load directly or bonded to/connected with a piece of elastic component, which essentially serves as an elastic spring) is always applied in these polymers to automatically reset the temporary shape in each cycle [128,129], according to the definition in [73], it is the mechanical two-way SME. Similar to that in SMAs, the material two-way SME, in which a piece of free-standing material is able to switch between two shapes during thermal cycling, is theoretically achievable (by means of introducing an elastic stress field at micro-scale into a polymer), but has yet been realized in real practice.…”

Section: Reversible Motionmentioning

confidence: 99%

Mechanisms of the Shape Memory Effect in Polymeric Materials

et al. 2013

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Abstract:This review paper summarizes the recent research progress in the underlying mechanisms behind the shape memory effect (SME) and some newly discovered shape memory phenomena in polymeric materials. It is revealed that most polymeric materials, if not all, intrinsically have the thermo/chemo-responsive SME. It is demonstrated that a good understanding of the fundamentals behind various types of shape memory phenomena in polymeric materials is not only useful in design/synthesis of new polymeric shape memory materials (SMMs) with tailored performance, but also helpful in optimization of the existing ones, and thus remarkably widens the application field of polymeric SMMs.

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Two-way reversible shape memory behaviour of crosslinked poly(ε-caprolactone)

Cited by 143 publications

References 33 publications

Shape-memory behavior of cross-linked semi-crystalline polymers and their blends

Shape-memory behavior of cross-linked semi-crystalline polymers and their blends

Biodegradable polyester-based shape memory polymers: Concepts of (supra)molecular architecturing

Mechanisms of the Shape Memory Effect in Polymeric Materials

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