Tailored One-Way and Two-Way Shape Memory Capabilities of Poly(ε-Caprolactone)-Based Systems for Biomedical Applications

Pandini, Stefano; Riccò, T.; Borboni, Alberto; Bodini, Ileana; Vetturi, David; Cambiaghi, Danilo; Toselli, Maurizio; Paderni, Katia; Messori, Massimo; Pilati, Francesco; Chiellini, Emo; Bartoli, Cristina

doi:10.1007/s11665-014-1033-5

Cited by 19 publications

(21 citation statements)

References 20 publications

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“…This suggests that the whole elongation originates from two distinguished mechanisms, which, on the basis of previous observation on similar PCL-based networks (Pandini et al, , 2013(Pandini et al, , 2014a(Pandini et al, , 2014b, are interpreted as follows. The less steep elongation process may be ascribed to an entropy elasticity effect: in fact, since the stiffness of a rubbery material decreases with temperature, the application of a fixed stress leads to an increase in strain as the cooling proceeds within the rubber-like behaviour region.…”

Section: Two-way Shape Memory Characterizationsupporting

confidence: 58%

The two-way shape memory behaviour of crosslinked poly(ε-caprolactone) systems with largely varied network density

Pandini

Dioni

Paderni

et al. 2015

Journal of Intelligent Material Systems and Structures

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The two-way shape memory behaviour of semicrystalline networks was investigated on systems based on poly(e-caprolactone) featuring significantly different network architecture. Crosslinked poly(e-caprolactone)s were prepared by thermal curing from methacrylic end-capped linear chains having various methacrylation degrees. By conveniently reducing the methacrylation degree, the crosslink density of cured materials was varied over a range of one order of magnitude, leading to comparable changes in the material compliance in the rubbery region, but only to moderate variations in melting and crystallization temperatures (T m and T c ) and in the crystallinity content. When subjected to constant non-zero stress and to cooling-heating cycles from above T m to below T c , the materials undergo a reversible two-way elongation-contraction effect, whose extent depends on material structure and applied stress. The structural changes in the crystalline phase accompanying the cooling-induced elongation were studied through differential scanning calorimetry and X-ray diffraction analyses. The elongation process involves different contributions of entropy-and crystallization-driven processes, whose amounts were investigated as a function of the loading conditions and the molecular architecture. The role of the network density towards a controlled two-way response is evidenced, showing that a proper value of the crosslink density has to be identified to maximize the two-way elongation capabilities.

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Section: Two-way Shape Memory Characterizationsupporting

confidence: 58%

The two-way shape memory behaviour of crosslinked poly(ε-caprolactone) systems with largely varied network density

Pandini

Dioni

Paderni

et al. 2015

Journal of Intelligent Material Systems and Structures

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“…Therefore, such difficulties in setting precise values of stress and strain from specimen to specimen prohibited a proper evaluation of the experimental errors by means of repeated experiments. However, previous experience on the one‐ and two‐way shape memory tests on various materials and further side‐experiments on the PCL nonwovens allowed us to estimate that the relative error may be considered to be about 1%, and in any case less than 10%. The values presented in Tables and were reasonably rounded to an according number of significant digits.…”

Section: Methodsmentioning

confidence: 95%

“…This behavior is referred as one‐way shape memory effect, since the triggered transformation is only that from the temporary to the permanent configuration. A fully reversible change between two specific configurations by application and removal of the stimulus, i.e., the so‐called two‐way shape memory effect, may be shown only by specific families of polymers, such as liquid crystalline elastomers and semicrystalline networks, and it allows to extend the system capabilities to continuously reversible applications …”

Section: Introductionmentioning

confidence: 99%

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Mutifunctional Electrospun Nonwoven Mats with Two‐Way Shape Memory Behavior Prepared from Sol–Gel Crosslinked Poly(ε‐Caprolactone)

Pandini

Agnelli

Merlettini

et al. 2017

Macro Materials & Eng

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Nonwoven fibrous mats based on semicrystalline networks are prepared starting from poly(ε-caprolactone) and properly combining electrospinning and sol-gel reactions. The mats are obtained as continuous, randomly oriented micrometric fibers with different network densities. The systems are subjected to thermomechanical cycles to investigate their one-way and two-way shape memory behavior. One-way tests aim at exploring the effects of the deformation temperature on the materials response, with particular interest to the less investigated cold-working conditions (i.e., deformation temperature below T m ). The materials display two-way shape memory capabilities (i.e., the ability to change between two distinguished shapes upon heating and cooling under a fixed nonzero stress) and the effect of the applied stress is explored. The shape memory characterization is accompanied by an ex situ SEM analysis, to describe the concurrent microstructural evolution during the macroscopic shape variation, and by the assessment of their biocompatibility, to explore the suitability of the nonwovens for biomedical applications.

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“…1 and Fig. 2, the heartbeat is reproduced using a linear motor [23][24][25][26][27][28] connected to a hydraulic cylinder with double effect: in this way, with a suitable law of motion is possible to flow the fluid within the circuit, and to adjust the heart's frequency. The parameters considered for linear motor choice are: -the force required to move the blood's mass; -the speed of fluid; -the necessary acceleration for movement.…”

Section: Testbenchmentioning

confidence: 99%

Test Bench Simulator for Heart Valves

Petrogalli

Mor

2016

MATEC Web of Conferences

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Abstract. The objective of this research is the creation of a testing bench prototype for comparing different types of heart valves, taking into account the variability of some important parameters involved in cardiovascular events. Thanks to performed tests and to obtained data, the comparison between the different valves allows physicians to make the most appropriate choice of heart valve for each patient. The study is still in preliminary stage: it is necessary to do many tests in order to obtain a large amount of data with which it is possible to proceed with the development and implementation of a testing bench stable and easily programmable.

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Tailored One-Way and Two-Way Shape Memory Capabilities of Poly(ε-Caprolactone)-Based Systems for Biomedical Applications

Cited by 19 publications

References 20 publications

The two-way shape memory behaviour of crosslinked poly(ε-caprolactone) systems with largely varied network density

The two-way shape memory behaviour of crosslinked poly(ε-caprolactone) systems with largely varied network density

Mutifunctional Electrospun Nonwoven Mats with Two‐Way Shape Memory Behavior Prepared from Sol–Gel Crosslinked Poly(ε‐Caprolactone)

Test Bench Simulator for Heart Valves

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