Effect of accelerated aging on the viscoelastic properties of Elast-Eon™: A polyurethane with soft poly(dimethylsiloxane) and poly(hexamethylene oxide) segments

Mahomed, Aziza; Hukins, D. W. L.; Kukureka, Stephen N.; Shepherd, Duncan E.T.

doi:10.1016/j.msec.2010.07.014

Cited by 15 publications

(15 citation statements)

References 37 publications

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“…As mentioned previously, aging of materials is associated with a number of property changes, and some polyurethane systems have demonstrated spectroscopic indicators of these changes in addition to loss of physical properties [12–18]. Acceleration of porous, segmented polyurethane aging was shown to decrease hydrogen bonding as a result of rearrangement of the hard segments.…”

Section: Introductionmentioning

confidence: 99%

Two-year performance study of porous, thermoset, shape memory polyurethanes intended for vascular medical devices

Weems

Boyle

Maitland

2017

Smart Mater. Struct.

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The long-term shape-recovery behavior of shape memory polymers has often been shown to be dependent on the length of time the material has been stored in the secondary shape. Typically, recovery performance and shape fixity will decrease with increased time in the secondary shape. In medical materials, a shelf-life is crucial to establish as it sets the upper threshold for device performance in a clinical setting, and a reduction in shape recovery would limit the development of SMP medical devices. Here, we present a two-year study of strain recovery, strain fixity, and shape recovery kinetics for passively and actively actuated SMPs intended for vascular devices. While kinetic experiments using immersion DMA indicate slight material relaxation and a decrease in the time to recovery, these changes are not found for bulk recovery experiments. The results indicate that a two-year shelf-life for these SMPs is very reasonable, as there is no change in the recovery kinetics, strain recovery, or strain fixity associated with this aging time. Further, a thermal accelerated aging test is presented for more rapid testing of the shape memory behavior of these SMPs and is compared with the real time aging results, indicating that this test is a reasonable indicator of the two-year behavior.

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Section: Introductionmentioning

confidence: 99%

Two-year performance study of porous, thermoset, shape memory polyurethanes intended for vascular medical devices

Weems

Boyle

Maitland

2017

Smart Mater. Struct.

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“…The same testing equipment and protocol were used in this investigation as described in work on silicone elastomers [16] and Elast-Eon™ [11]. Once a test started, the system ramped the load to 40 N and held it there for 5 seconds to allow for any creep to occur before testing.…”

Section: Measuring Viscoelastic Propertiesmentioning

confidence: 99%

“…E' represents the elastic response of the material, where the work done in deforming the material is stored as potential energy that is subsequently used for recoil [12,13] ; E'' represents the viscous response of the material, where the energy supplied to the material is dissipated [12,13]. The purpose of this paper, is to measure the storage, E', and loss, E'', moduli, as a function of frequency, f, in compression, before and after accelerated aging, of a silicone elastomer (Nagor) and compare it to the results obtained for the polymer Elast-Eon™ 3 (a polyurethane containing PDMS segments) [11]. Silicone was used for comparison with Elast-Eon TM because it is also used in similar biomedical applications.…”

Section: Introductionmentioning

confidence: 99%

Effect of accelerated aging on the viscoelastic properties of a medical grade silicone

Mahomed

Hukins

Kukureka

2015

BME

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The viscoelastic properties of cylinders (diameter 5 mm, height 2.2 ± 0.2 mm) of Nagor silicone elastomer of medium hardness, were investigated before and after the specimens had undergone accelerated aging in saline solution at 70°C for 38, 76 and 114 days (to simulate aging at 37°C, for 1, 2 and 3 years, respectively). All sets of specimens were immersed in physiological saline solution at 37°C during testing and the properties were measured using dynamic mechanical analysis (DMA). A sinusoidal cyclic compression of 40 N ± 5 N was applied over a frequency range, f, of 0.02-25 Hz. Values of the storage, E', and loss, E″, moduli were found to depend on f; the dependence of E' or E″ on the logarithm (base 10) of f was represented by a second-order polynomial. After accelerated aging, the E' and E″ values did not increase significantly (p<0.05). Furthermore, scanning electron microscopy (SEM) showed that accelerated aging did not affect the surface morphology of silicone. Attenuated total reflectance Fourier transform infra-red spectroscopy (ATR-FTIR) showed that accelerated aging had a negligible effect on the surface chemical structures of the material. Differential scanning calorimetry (DSC) showed no changes to the bulk properties of silicone, following accelerated aging.

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“…Ubrzano starenje je vršeno tako što su uzorci potopljeni u vodu temperature 70 °C [23,24]. Uzorci za ispitivanje žilavosti i mehaničkih svojstava zatezanjem su izvađeni nakon 30 dana, dok su uzorci za ispitivanje tvrdoće vađeni nakon 7, 15 i 30 dana.…”

Section: Ubrzano Starenjeunclassified

“…Konvencionalni način prevazilaženja ovih problema je podvrgavanje materijala povišenoj temperaturi, takozvano ubrzano starenje. Najčešće se pretpostavlja da se brzina starenja ubrzava za faktor 2 ΔT/10 za povećenje temperature od ΔT [23]. Ovo je matematički izraz koji je nastao iz mnogih empirijskih zapažanja da povećanje temperature za 10 °C dvostruko povećava brzinu mnogih polimernih reakcija, a to je ekvivalentno pretpostavci da se proces starenje može opisati reakcijom prvog reda sa energijom aktivacije od 10R/ln 2, gde je R univerzana gasna konstanta.…”

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The effect of the accelerated aging on the mechanical properties of the PMMA denture base materials modified with itaconates

Spasojević¹,

Zrilić²,

Stamenković

et al. 2011

Hem Ind

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This study evaluated the effect of accelerated ageing on the tensile strength, elongation at break, hardness and Charpy impact strength in commercial PMMA denture base material modified with di-methyl itaconate (DMI) and di-n-butyl itaconate (DBI). The samples were prepared by modifying commercial formulation by addition of itaconates in the amounts of 2.5, 5, 7.5 and 10% by weight. After polymerization samples were characterized by FT-IR and DSC analysis while residual monomer content was determined by HPLC-UV. Accelerated ageing was performed at 70°C in water for periods of 7, 15 and 30 days. Tensile measurements were performed using Instron testing machine while the hardness of the polymerized samples was measured by Shore D method. The addition of itaconate significantly reduces the residual MMA. Even at the small amounts of added itaconates (2.5%) the residual MMA content was reduced by 50%. The increase of itaconate content in the system leads to the decrease of residual MMA. It has been found that the addition of di-n-alkyl itaconates decreases the tensile strength, hardness and Charpy impact strength and increases elongation at break. Samples modified with DMI had higher values of tensile strength, hardness and Charpy impact strength compared to the ones modified with DBI. This is explained by the fact that DBI has longer side chain compared to DMI. After accelerated ageing during a 30 days period the tensile strength decreased for all the investigated samples. The addition of DMI had no effect on the material ageing and the values for the tensile strength of all of the investigated samples decreased around 20%, while for the samples modified with DBI, the increase of the amount of DBI in the polymerized material leads to the higher decrease of the tensile strength after the complete accelerated ageing period od 30 days, aulthough after the first seven days of the accelerated ageing the values of hardness have increased for all of the investigated samples. Such behavior is explained as the result of the polymer chain relaxation. The values of Charpy impact strength decreased after accelerated ageing. The amount of added DMI have no affect on the decrease of Charpy impact strength after accelerated ageing, the decrease was similar as for pure PMMA. The decrease of Charpy impact strength increased as the amount of added DBI increases

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Effect of accelerated aging on the viscoelastic properties of Elast-Eon™: A polyurethane with soft poly(dimethylsiloxane) and poly(hexamethylene oxide) segments

Cited by 15 publications

References 37 publications

Two-year performance study of porous, thermoset, shape memory polyurethanes intended for vascular medical devices

Two-year performance study of porous, thermoset, shape memory polyurethanes intended for vascular medical devices

Effect of accelerated aging on the viscoelastic properties of a medical grade silicone

The effect of the accelerated aging on the mechanical properties of the PMMA denture base materials modified with itaconates

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