Viscoelastic Behaviour of Polymers

doi:10.1007/978-1-4020-9372-2_2

Cited by 6 publications

(3 citation statements)

References 171 publications

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“…As shown in Figure 3 a,b, the loss tangent for alginates is <1 over the range of dynamic frequencies (overall range 0.133–0.539); that is why they behave as solids and amorphous-like polymers. However, the loss tangent profiles ( Figure 3 b) suggest that the temperature has some effect, especially on AF alginates [ 37 , 38 , 39 ].…”

Section: Resultsmentioning

confidence: 99%

Protective Effect of Alginate Microcapsules with Different Rheological Behavior on Lactiplantibacillus plantarum 299v

Hernández-Gallegos,

Solorza-Feria,

Cornejo-Mazón

et al. 2023

Gels

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Alginate encapsulation is a well-known technique used to protect microorganisms from adverse conditions. However, it is also known that the viscosity of the alginate is dependent on its composition and degree of polymerization and that thermal treatments, such as pasteurization and sterilization, can affect the structure of the polymer and decrease its protection efficiency. The goal of this study was to evaluate the protective effect of encapsulation, using alginates of different viscosities treated at different temperatures, on Lactiplantibacillus plantarum 299v under in vitro gastrointestinal conditions and cold storage at 4 °C and −15 °C, respectively. Steady- and dynamic-shear rheological tests were used to characterize the polymers. Thermal treatments profoundly affected the rheological characteristics of alginates with high and low viscosity. However, the solutions and gels of the low-viscosity alginate were more affected at a temperature of 117 °C. The capsules elaborated with high-viscosity alginate solution and pasteurized at 63 °C for 30 min provided better protection to the cells of L. plantarum 299v under simulated gastrointestinal and cold storage conditions.

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Section: Resultsmentioning

confidence: 99%

Protective Effect of Alginate Microcapsules with Different Rheological Behavior on Lactiplantibacillus plantarum 299v

Hernández-Gallegos,

Solorza-Feria,

Cornejo-Mazón

et al. 2023

Gels

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“…[H3] Mechanical failure Plastics have unique mechanical properties that are time dependent, often nonlinear and these affect their performance in the long term 113 . When a controlled force (stress) is applied to a plastic, it causes a change in its size (strain), which is initially proportionate to the force applied (linear elasticity) 114 . This proportionality is lost at some point during loading and the stress strain curve becomes nonlinear and the material starts to deform irreversibly, whereas it remains elastic when the curve is linear 114 (Figure 5).…”

Section: [H3] Biocompatibilitymentioning

confidence: 99%

Landmarks in vaginal mesh development: polypropylene mesh for treatment of SUI and POP

et al. 2019

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Vaginal meshes used in the treatment of stress urinary incontinence (SUI) and pelvic organ prolapse (POP) have produced highly variable outcomes causing life-changing complications in some patients while providing others with effective, minimally invasive treatments. The issue surrounding the risk:benefit ratio when using the vaginal meshes is complex in which a combination of several factors, including the inherent incompatibility of the mesh material with some applications in pelvic reconstructive surgeries and the lack of appropriate regulatory approval processes at the time of premarket clearance of these products , have contributed to occurrence of complications caused by vaginal mesh. Surgical mesh used in hernia repair has evolved over many years from metal implants to knitted polymer meshes that were adopted for use in the pelvic floor for treatment of POP and SUI. The evolution of the material and textile properties of the surgical mesh was guided by clinical feedback from hernia repair procedures, which were also being modified to obtain the best outcomes with use of the mesh. Current evidence shows how surgical mesh fails biomechanically when used in pelvic floor and materials with improved performance can be developed using modern material processing and tissue engineering techniques. [H1] IntroductionVaginal meshes that are currently used in the surgical treatment of stress urinary incontinence (SUI) and pelvic organ prolapse (POP) can result in life-changing complications in some women who have vaginal mesh implants 1 . These adverse outcomes are now considered a major public health problem; New Zealand becoming the first country in the world to ban the use of transvaginal POP mesh products while still allowing transvaginal SUI meshes (except minislings) in December 2017 2 . In the UK, two public enquiries performed by the Scottish (in 2015) 3 and English (in 2017) 4 governments, in part, as a result of pressure from patient groups led to suspension of vaginal mesh products, both for SUI and POP, from July 2018 onwards 5 . The newest guidance by the National Institute of Health and Care Excellence (NICE) in the UK recommends that retropubic sling materials can be offered to women with SUI if nonsurgical management has failed 6 . In response, the British Society of Urogynaecologists expressed strong disagreement with the decision to suspend the use of vaginal mesh for SUI, but not POP, stating that this decision would deprive many women of an effective and safe treatment option as demonstrated by level I evidence 7 8 . Mesh manufacturers are currently facing lawsuits in the USA and Europe 9 . The issue with mesh repairs for SUI and POP is complex, as the vaginal mesh is implanted in the female pelvic floor in several different ways with very different outcomes in efficacy and complication outcomes. When used as a tape to treat SUI, many patients are effectively cured with the benefits outweighing the risks 10,11 , whereas when used for transvaginal POP repair, complications are more frequent 12 with...

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“…This type of bond produces more frictional force between the polymeric chains because of their viscoelastic nature. 21 Some researchers have studied the evolution of the hysteresis area per cycle. 15,18 However, few works have shown the influence of stress levels on that material in terms of dissipated energy.…”

Section: Introductionmentioning

confidence: 99%

Observations of fatigue damage development in woven glass fiber-reinforced polymer composite using transmission light photography technique

Ansari

Singh

Azam

2022

Polymers and Polymer Composites

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Fatigue behaviour is an important aspect for consideration while handling glass fiber-reinforced polymer (GFRP) composites. A combination of (0°/90°) and (±45°) plies are gaining practical interest in engineering applications due to their excellent mechanical properties. Properties of individual above-stated plies primarily influence the behaviour of laminates. Fatigue behaviour of on-axis (0°/90°) and off-axis (±45°) fiber orientated woven GFRP laminates was investigated. Tensile and tension-tension fatigue tests were performed on the prepared test coupons according to the ASTM standard. Fatigue test was conducted until failure at maximum applied stress of 90%, 70%, and 50% of the respective ultimate strength. Damage growth was monitored in the term of debond zones by employing the transmission light photography technique. Testing process was recorded by using a digital camera. The results were established in terms of the stress-strain curve, Wöhler curve, debond zones and dynamic stiffness. The fatigue strength of off-axis laminates was much lower than the on-axis laminates. Global damage has occurred in (0°/90°) laminates while (±45°) laminate witnessed localized damage. At higher stress levels, samples were failed at shorter lifespan with aggressive damage; however, on-axis specimens survived with longer fatigue life.

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Viscoelastic Behaviour of Polymers

Cited by 6 publications

References 171 publications

Protective Effect of Alginate Microcapsules with Different Rheological Behavior on Lactiplantibacillus plantarum 299v

Protective Effect of Alginate Microcapsules with Different Rheological Behavior on Lactiplantibacillus plantarum 299v

Landmarks in vaginal mesh development: polypropylene mesh for treatment of SUI and POP

Observations of fatigue damage development in woven glass fiber-reinforced polymer composite using transmission light photography technique

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