Molecular Simulation of Thermoplastic Polyurethanes under Large Compressive Deformation

Zhu, Songming; Lempesis, Nikolaos; Veld, Pieter J. in ’t

doi:10.1021/acs.macromol.8b01922

Cited by 30 publications

(15 citation statements)

References 32 publications

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“…Within the filled soft phase, there are multiple hard-phase "islands", with soft segments acting as bridges or loops. 29,62,63 The distribution of relaxation times depends on the average length of the hard segment, the balance between the "bridges" and "loops" (similar to the case of associative thickeners on nanoparticles 64 ), and the quality of the hydrogen bonds holding the hard-phase islands together. Developing a model to capture all these details remains a major challenge.…”

Section: Modeling Resultsmentioning

confidence: 99%

Experimental and modeling studies of IPDI‐based polyurea elastomers – The role of hard segment fraction

Tzelepis

Suzuki

et al. 2023

J of Applied Polymer Sci

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Segmented polyureas (PUa) are industrially important class of polymers widely used in coatings, sealant, and adhesive applications. Here, we report synthesis, characterization, and modeling of Isophorone Diisocyanate-Diethyl-Toluene-Diamine-Polyether amine (IPDI-DETDA-PO PUa) with varied hard segment contents of 20, 30, and 40 weight percent. For each of the three materials, we study its structure and phase behavior using FTIR, DSC, and TEM, and clearly show the presence of microphase separation between the hard and soft nanodomains. We then measure the linear viscoelastic response of the PUa-s using DMA (frequency sweeps at multiple temperatures). The DMA data are shown to obey the time-temperature superposition. Finally, we develop a new micromechanical model describing the DMA results; the model describes a phaseseparated PUa as two "Fractional-order Maxwell gels" branches, connected in parallel, with the first FMG branch representing the "percolated hard phase" and the second one modeling the "filled soft phase". In agreement with the earlier thermodynamic theories, the volume-fraction of the percolated hard phase is related to the hard segment weight-fraction (HSWF), defined as the combined mass of IPDI and DETDA normalized to the total mass of the polymer. The data and model are found to be in a good qualitative and quantitative agreement.adhesive, dynamic mechanical analysis, fractional calculus, hard domains, polyurea, time temperature superposition | INTRODUCTIONPolyurethanes (PU), polyureas (PUa), and poly (urethaneureas) (PUU) represent a fascinating family of polymers. [1][2][3][4] Their applications include coatings, 5 adhesives and sealants, 6,7 elastomers, 8 as well as rigid foams for thermal insulation 9 and flexible foams for furnishings

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Section: Modeling Resultsmentioning

confidence: 99%

Experimental and modeling studies of IPDI‐based polyurea elastomers – The role of hard segment fraction

Tzelepis

Suzuki

et al. 2023

J of Applied Polymer Sci

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“…Moreover, enhanced f 1 is also contributed by high Φ and thereby a large F 1 of nanofibers and compressive stress of the buck aerogels 34. At the molecular level, the flexibility was analyzed based on the intramolecular rotation of BMI monomers 35 Figure 2g,h. presents the rotatable single bonds along the main chains of PDM, BDM, and BMP and their corresponding potential energies.…”

Section: Resultsmentioning

confidence: 99%

“…[34] At the molecular level, the flexibility was analyzed based on the intramolecular rotation of BMI monomers. [35] Figure 2g,h presents the rotatable single bonds along the main chains of PDM, BDM, and BMP and their corresponding potential energies. The potential energy curves of α and α′ bonds overlapped due to the structural symmetry of the BMIs.…”

Section: Figure 2bmentioning

confidence: 99%

Semi‐Interpenetrating Polymer Network Biomimetic Structure Enables Superelastic and Thermostable Nanofibrous Aerogels for Cascade Filtration of PM_2.5

Cao

Yin

et al. 2020

Adv Funct Materials

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Particulate matter (PM) has taken heavy tolls on the global economy and public health, calling for air filters that can remove PM from high‐temperature emission sources. However, creating desirable filter media capable of capturing polydisperse fine particles (PFPs) effectively and enduringly, while also withstanding high speed airstream, is extremely challenging. Here, a biomimetic and bottom‐up strategy to prepare superelastic, strong, and thermostable nanofibrous aerogels (NFAs) as cascade filters by assembling semi‐interpenetrating polymer network (semi‐IPN)‐based nanofibers into a gradient architecture is reported. Inspired by the robust loofah sponges originating from stiff cellulose networks, the mechanical property of NFAs is enhanced via tailoring the chain flexibility of heat‐resistant semi‐IPNs. Further constructing a gradient cellular architecture endows NFAs with a versatile cascade filtration behavior for capturing polydisperse fine particles. The resultant semi‐IPN‐based gradient NFAs exhibit temperature‐invariant superelasticity, a high compressive stress (7.9 kPa) and modulus (12 kPa), high filtration efficiency (>99.97%, PM0.3), low pressure drop (≈50% that of membranes), and ultrahigh dust‐holding capacity (114 g m−2). The fabrication of this attractive material paves the way for designing next‐generation air filters for industrial dust removal.

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“…Historical data and data modeling are increasingly used for the development of structure-property relationships. [44][45][46][47] Recently, models based on descriptor analyses were proposed that showed satisfactory recipeproperties correlations. 48 Can these models be extended so that also the effects of processing are considered?…”

Section: Discussionmentioning

confidence: 99%

Block length distribution, morphology, and property of thermoplastic polyurethanes affected by production method: A polymer‐by‐process investigation

Liu

Wang

et al. 2023

Journal of Polymer Science

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Two thermoplastic polyurethanes (TPUs) based on the same monomers and composition were produced by two different production methods – hand mix batch process and continuous band casting. The soft segment was poly(hydrofuran) (PTHF) with a molar mass of 1000 and the hard segment was made of 1,4‐butanediol (BD) and 4,4′‐methylene diphenyl diisocyanate (MDI). The hard segment content amounted to 42%. The distinctions in crystallization and thermal behavior and mechanical properties of the two TPUs were ascribed to differences in the hard and soft block length distribution caused by the different production methods. Using thermal fractionation – a series of successive self‐nucleation and annealing steps – the minor differences in hard block length distribution could be shown and quantified. The length distribution of the hard and soft blocks of the machine‐produced sample was narrower than that of the hand‐cast sample. The former with the narrow block distribution showed thicker and mechanically and thermally more stable hard domains. The more uniform block length distribution facilitated crystallization and resulted in improved tensile recovery behavior and elasticity. The second with the broader distribution, however, showed the highest tensile strength at break, which was ascribed to an improved strain‐induced hardening of the soft phase.

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Molecular Simulation of Thermoplastic Polyurethanes under Large Compressive Deformation

Cited by 30 publications

References 32 publications

Experimental and modeling studies of IPDI‐based polyurea elastomers – The role of hard segment fraction

Experimental and modeling studies of IPDI‐based polyurea elastomers – The role of hard segment fraction

Semi‐Interpenetrating Polymer Network Biomimetic Structure Enables Superelastic and Thermostable Nanofibrous Aerogels for Cascade Filtration of PM_2.5

Block length distribution, morphology, and property of thermoplastic polyurethanes affected by production method: A polymer‐by‐process investigation

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Molecular Simulation of Thermoplastic Polyurethanes under Large Compressive Deformation

Cited by 30 publications

References 32 publications

Experimental and modeling studies of IPDI‐based polyurea elastomers – The role of hard segment fraction

Experimental and modeling studies of IPDI‐based polyurea elastomers – The role of hard segment fraction

Semi‐Interpenetrating Polymer Network Biomimetic Structure Enables Superelastic and Thermostable Nanofibrous Aerogels for Cascade Filtration of PM2.5

Block length distribution, morphology, and property of thermoplastic polyurethanes affected by production method: A polymer‐by‐process investigation

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Semi‐Interpenetrating Polymer Network Biomimetic Structure Enables Superelastic and Thermostable Nanofibrous Aerogels for Cascade Filtration of PM_2.5