The Effect of Ultraviolet Radiation on the Hyperelastic Behavior of Polyurea

Youssef, George; Brinson, Joseph; Whitten, Ian

doi:10.1007/s10924-016-0933-x

Cited by 32 publications

(11 citation statements)

References 25 publications

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“…All the constituents were at ambient conditions (~23 °C and ~24% relative humidity) before mixing, where the mixing process also took place at room temperature. Based on prior research by our group, the ratio of Versalink to Isonate was kept to 4:1 weight ratio given it results in hyper‐viscoelastic polyurea response . The mold was coated with nonstick Teflon spray to facilitate the quick release of the cured foam sheets.…”

Section: Sample Preparationmentioning

confidence: 99%

“…Based on prior research by our group, the ratio of Versalink to Isonate was kept to 4:1 weight ratio given it results in hyper-viscoelastic polyurea response. 19,20 The mold was coated with nonstick Teflon spray to facilitate the quick release of the cured foam sheets. Once the constituents were mechanically and thoroughly mixed, the resulting slurry was quickly poured in the mold to avoid the initiation of curing within the mixing pot.…”

Section: Sample Preparationmentioning

confidence: 99%

“…Grujici and coworkers attributed the ability of polyurea to exceptionally perform in such loading scenarios to the underlying molecular structure . In addition, polyurea was investigated in response to different environmental and operating conditions such as temperature, humidity, and ultraviolet radiation, all of which confirmed its superior overall properties …”

Section: Introductionmentioning

confidence: 99%

“…17 In addition, polyurea was investigated in response to different environmental and operating conditions such as temperature, humidity, and ultraviolet radiation, all of which confirmed its superior overall properties. [18][19][20][21] In here, the focus of this research is on the synthesis and quasistatic characterization of a novel polyurea foam with different density for potential integration in biomechanical impact mitigation applications. The quasi-static behavior, that is, stress-strain response, was used to predict the performance of polyurea foams in dynamic loading scenarios.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and characterization of elastomeric polyurea foam

Reed

Huynh

Rosenow

et al. 2019

J of Applied Polymer Sci

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Polymeric foams are ubiquitous in impact mitigation for civilian and military applications; the performance in such loading scenarios can be elucidated through quasi‐static and dynamic mechanical testing. The present study reports on the complex microstructure of newly synthesized polyurea foams exhibiting a hierarchical structure consisting of large perforated semi‐closed spherical cells with a mean diameter of 370 ± 162 μm surrounded by smaller closed, spherical cells with size distribution of 69 ± 18 μm. The stress–strain curves were used to calculate the basic mechanical properties and to predict the dynamic behavior of the foams. Nonlinear regression and finite element analyses were used to calibrate the Ogden hyperfoam model to explicate the hyperelastic behavior. The performance of the polyurea foam was found to outperform a benchmark foam in nearly all the elastic and energy absorbing properties. For example, one variation of the newly synthesized foam stored nearly doubled the energy of the benchmark foam while being 12% lighter. Low‐density polyurea foam was found to decelerate an incoming impact mass with a minimum G‐level that was nearly one third lower than the higher density polyurea and benchmark foams. In all, the behavior of the foam is dependent on the parameters of the fabrication process. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48839.

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Section: Sample Preparationmentioning

confidence: 99%

Section: Sample Preparationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Synthesis and characterization of elastomeric polyurea foam

Reed

Huynh

Rosenow

et al. 2019

J of Applied Polymer Sci

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“…Mechanisms of photoassisted degradation of polymers are usually complex and involve many pathways for the chemical reactions due to the high activity of photogenerated radicals, which subsequently unselectively attack polymer chain resulting in multiple products of decomposition [26]. Nevertheless, the common initial reaction during photodegradation is scission of polymer chains forming at least two chain ends.…”

Section: Measurement Of the Degree Of Photodegradationmentioning

confidence: 99%

Inhibition of Polyimide Photodegradation by Incorporation of Titanate Nanotubes into a Composite

et al. 2019

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The effect of UV light exposure on the properties of hexafluoroisopropylidene-diphthalic anhydride-oxydianiline (6FDA-ODA) polyimide (PI) and polyimide-titanate nanotube (TiNT/PI) composites has been studied using Raman spectroscopy, optical microscopy, nanoidentation and TEM. The degree of polymer photodegradation was estimated by measuring the change in affinity to a positively charged dye (methylene blue, MB). The mechanism of photoassisted transformations in polyimides usually involves scission of polymer chains accompanied by appearance of active radicals, which undergo further rapid transformations to more stable phenol, amine, and carboxylic functional groups. The accumulation of these groups can increase the degree of adsorption of charged dyes in the photodegraded polymer. It was found that neat PI showed a significantly increased capacity to adsorb MB after irradiation with UV, reaching a plateau after 1 h. In contrast, TiNT/PI composite demonstrated a much slower rise in concentration of adsorbed MB even after 4 h of UV exposure. Raman spectra indicated cleavage of C=O and C-F bonds in PI while only the C-F bond was damaged in TiNT/PI. Shorter cracks (≈ 40 µm long) appeared in TiNT/PI composites whereas macro cracks (> 100 µm) were visible in neat PI after 3 h of UV exposure. Brittleness was studied by comparing plasticity index which varied from 0 to 1 (0 corresponding to the most brittle material and 1 the most ductile one). Plasticity index reduced by 51% and 2% for PI and TiNT/PI, respectively after 3 h UV irradiation, indicating that TiNT can protect underlying PI from further damage. The hardness of neat PI decreased whereas, for TiNT/PI, it increased under UV, suggesting crosslinking of broken polymer chains with nanotubes. Graphical AbstractPhotodegradation of a titanate nanotubes/polyimide composite can lead to cross-linking of broken polymer chains by nanostructured material, resulting in increased hardness.

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Development of nanostructured green divalent manganese‐coordinated polyurea

Laxmi

Shahzaib

Alam

et al. 2022

J of Applied Polymer Sci

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The work presented here reports the greener synthesis of polyurea (GPUa) via in-situ solvent-free precipitation polymerization of toluene diisocyanate (TDI) (used as monomer) and water. The divalent manganese [Mn(II)] ions were incorporated into GPUa to form Mn(II)-GPUa to enhance its applicability. The structure of GPUa and Mn(II)-GPUa was validated by Fourier-transform infrared and proton nuclear magnetic resonance spectral techniques. The morphology along with the elemental analysis of GPUa and Mn(II)-GPUa was assessed by X-ray diffraction analysis and field emission scanning electron microscopy along with energy-dispersive X-ray spectroscopy. Thermal degradation behavior and stability of GPUa and Mn(II)-GPUa were investigated by thermo-gravimetric, differential thermal, differential scanning calorimetry, and integral procedure decomposition temperature analysis. Furthermore, the batch adsorption method was used to examine the adsorption behavior of Mn(II)-GPUa. The study's results indicated that Mn(II)-GPUa might be used as an eco-friendly, thermally stable material and adsorbent, making it suitable as an effective dye adsorbent for wastewater treatment. The current work is aligned with Green chemistry principles (Principles 1,2,3,4,5,6,8,and 12).

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The Effect of Ultraviolet Radiation on the Hyperelastic Behavior of Polyurea

Cited by 32 publications

References 25 publications

Synthesis and characterization of elastomeric polyurea foam

Synthesis and characterization of elastomeric polyurea foam

Inhibition of Polyimide Photodegradation by Incorporation of Titanate Nanotubes into a Composite

Development of nanostructured green divalent manganese‐coordinated polyurea

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