New insight into microstructure-mediated segmental dynamics in select model poly(urethane urea) elastomers

Hsieh, Alex J.; Chantawansri, Tanya L.; Hu, Weiguo; Strawhecker, Kenneth E.; Casem, Daniel; Eliason, Jeffrey K.; Nelson, Keith A.; Parsons, Ethan M.

doi:10.1016/j.polymer.2014.02.037

Cited by 22 publications

(22 citation statements)

References 40 publications

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“…This leads to some experimental challenges in identifying and designing suitable polymers, for it is far above the range of frequencies at which polymers are typically investigated. However, ultrasonic methods (Alig et al, 1991) and dielectric analyses (Hsieh et al, 2014) have been used to measure tan δ and the storage and loss moduli in the MHz range.…”

Section: Discussionmentioning

confidence: 99%

“…The higher the frequency, the less material is needed to dissipate the energy (for a given wave speed). The potential materials challenge from a development perspective is that the frequencies associated with this tuning will be in a range for which the properties of polymers have only received limited study (Alig et al, 1991;Rowland and Casalini, 2007;Bogoslovov et al, 2007;Hsieh et al, 2014).…”

Section: The Concept Of Tuningmentioning

confidence: 99%

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Design of armor for protection against blast and impact

Rahimzadeh

Arruda

Thouless

2015

Journal of the Mechanics and Physics of Solids

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a b s t r a c tThe features of blast and impact that can damage a delicate target supported by a structure include both the peak pressure and the impulse delivered to the structure. This study examines how layers of elastic and visco-elastic materials may be assembled to mitigate these features. The impedance mismatch between two elastic layers is known to reduce the pressure, but dissipation is required to mitigate the transmitted impulse in light-weight armor. A novel design concept called impact or blast tuning is introduced in which a multi-layered armor is used to tune the stress waves resulting from an impact or blast to specific frequencies that match the damping frequencies of visco-elastic layers. The material and geometrical parameters controlling the viscous dissipation of the energy within the armor are identified for a simplified one-dimensional system, to provide insight into how the optimal design of multi-use armor might be based on this concept.

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Section: Discussionmentioning

confidence: 99%

Section: The Concept Of Tuningmentioning

confidence: 99%

Design of armor for protection against blast and impact

Rahimzadeh

Arruda

Thouless

2015

Journal of the Mechanics and Physics of Solids

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“…PUUs are composed of urethane and urea linkages; the versatile chemistry and intrinsic intermolecular hydrogen bonding in these segmented PUUs like in segmented polyurethane and polyurea elastomers give rise to complex microstructure and a broad range of physical and mechanical properties [5][6][7][8][9][10][11][12][13]. The motivation towards hierarchical elastomers was derived from a novel molecular mechanism  high-rate deformation-induced glass transition, revealed by Bogoslovov et al [14], which was successfully used to explain why a thin layer of polyurea coating on a steel plate was capable of providing ballistic protection against penetration by a 50 cal.…”

Section: Introductionmentioning

confidence: 99%

“…bullet [15]. These elastomeric materials have regained significant interest particularly for their potential in the areas of enhanced ballistic impact protection and shock wave mitigation capability [8,[12][13][14][15][16][17][18][19]. However, challenges remain to fully understand the efficacy of molecular attributes that would provide guidance to enable better selection of the proper high performance elastomers required for the overall dynamic impact deformation optimization.…”

Section: Introductionmentioning

confidence: 99%

“…when  =1 [23]. Broadband dielectric spectroscopy measurements revealed a drastic difference in dielectric relaxation and the corresponding segmental mobility among three select PUUs, which consist of 4,4'-dicyclohexylmethane diisocyanate (HMDI), diethyltoluenediamine (DETA), and poly(tetramethylene oxide) (PTMO), having the same stoichiometric ratio, 2:1:1 of [HMDI]:[DETA]:[PTMO] but varying in the molecular weight of PTMO (650, 1,000 and 2,000 g/mol), namely 211-650, 211-1000, and 211-2000, respectively [8]. The 211-650 PUU exhibited a strong relaxation at ~ 8 Hz along with a second loss maximum at ~ 4,600 Hz.…”

Section: Introductionmentioning

confidence: 99%

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Molecular influence in high-strain-rate microparticle impact response of poly(urethane urea) elastomers

Veysset

Hsieh

Kooi

et al. 2017

Polymer

Self Cite

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Physical properties and dielectric behavior of the poly(urethane‐urea) based on o‐dianisidine and renewable cross‐linkers

Oprea

Potolinca

Oprea

2021

J of Applied Polymer Sci

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The novelty of the poly(urethane-urea) series consists in inclusion of odianisidine units in the main chain and cross-linking with renewable biomaterials, unused compounds so far in the synthesis of the poly(urethane-urea) (Tween 20, Span 20, Phloroglucinol). The effects of these components on the structure, surface, thermo-mechanical properties and dielectric behavior of the obtained poly(urethane-urea) were investigated by Fourier transform infrared (FTIR) spectroscopy, thermo-gravimetric analysis, static contact angles, broadband dielectric spectroscopy, and mechanical testing. The FTIR spectra showed that the urethane hydrogen bonds decreased with the increase of odianisidine content. Such that, at the increase of the o-dianisidine content, decreased the thermo-mechanical properties, and increased strongly the water contact angle from 83 to 108. By dielectric relaxation spectroscopy was studied the molecular dynamics within the polymeric matrices with identical soft segments but different structure of the hard domains. These poly(urethane-urea) materials exhibit two secondary relaxations (β and γ) and a relaxation process α, corresponding to the segmental movements in the soft phase, which occurs around the temperature of −50 C independent of the measurement frequency. o-Dianisidine prevents the formation of all the urethane hydrogen bonds and so increases the chains mobility and dipoles polarization of polymer matrix, thus increasing the dielectric constants.

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New insight into microstructure-mediated segmental dynamics in select model poly(urethane urea) elastomers

Cited by 22 publications

References 40 publications

Design of armor for protection against blast and impact

Design of armor for protection against blast and impact

Molecular influence in high-strain-rate microparticle impact response of poly(urethane urea) elastomers

Physical properties and dielectric behavior of the poly(urethane‐urea) based on o‐dianisidine and renewable cross‐linkers

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