Theoretical modeling of the relationship between Young's modulus and formulation variables for segmented polyurethanes

Ginzburg, Valeriy V.; Bicerano, Jozef; Christenson, C. P.; Schrock, Alan K.; Patashinski, Alexander Z.

doi:10.1002/polb.21213

Cited by 44 publications

(58 citation statements)

References 62 publications

(94 reference statements)

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“…Such domains form due to the thermodynamic incompatibility between hard and soft segments, strong hydrogen bonding interactions between hard segments as well as crystallization of hard segments . Some researchers have tried to explain TPU morphology using classic concepts of the copolymers and predict the system morphological features by estimating Flory–Huggins solubility parameter “

χ

,” degree of polymerization, and volume fraction of the hard segment phase in conjunction with the universal phase diagram for copolymers. Despite some successes, this approach leads to oversimplification in other cases.…”

Section: Introductionmentioning

confidence: 99%

Revisiting thermoplastic polyurethane, from composition to morphology and properties

Bonab

Manas‐Zloczower

2017

J Polym Sci B Polym Phys

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Thermoplastic polyurethanes (TPUs) are among the most versatile engineering polymers. The presence of hard and soft segments on their backbone and specific hydrogen bond interactions between the hard segments, provide TPUs with outstanding engineering properties while rendering them as very complex systems to study. Knowledge of morphology–property relationship is essential for TPUs since their thermal and mechanical behavior are directly dictated by their complicated morphology. In this research, TPU morphological features related to the hard segment content (HSC) were explored in tandem with system macroscopic properties. It was observed that TPUs display multiscale phase separated morphology with specific morphological features dependent on the HSC. At a certain critical HSC, an interconnected network of hard segments was formed which resulted in significant changes in TPU properties. This was explained in analogy with percolation phenomena in filler reinforced systems and considering the hard segments as reinforcing agent. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 1553–1564

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χ

Section: Introductionmentioning

confidence: 99%

Revisiting thermoplastic polyurethane, from composition to morphology and properties

Bonab

Manas‐Zloczower

2017

J Polym Sci B Polym Phys

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“…The micro-domain structure varies with the hard segment content and can exhibit a variety of different morphologies, such as sphere, cylinder and lamellar as predicted theoretically. 15 In reality, segmented polyurethanes actually exhibit a very complex morphology arising from polydispersity of the hard and soft blocks and the varying degrees of phase domain purity. The size and purity of the domains control the elastomeric nature and properties of these polymers.…”

Section: Resultsmentioning

confidence: 99%

Polyurethane elastomers based on 1,3 and 1,4‐bis(isocyanatomethyl)cyclohexane

Xie

Bhattacharjee

Argyropoulos

2009

J of Applied Polymer Sci

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Most polyurethane elastomers in the market place are based on aromatic isocyanates. This is partially due to the higher cost of aliphatic isocyanates compared with aromatic isocyanates which are commonly used by the industry. However, more importantly, it has been the performance deficiency of polyurethane elastomers based on commercial aliphatic isocyanates that has significantly limited their use. Though aliphatic-based polyurethane elastomers possess increased resistance to hydrolysis and thermal degradation in addition to greater light stability, these elastomers often experience a decrease in physical-mechanical properties when compared with aromatic isocyanate-based materials. In this study, we investigated elastomers based on 1,3 and 1,4-bis(isocyanatomethyl)cyclohexane, an experimental diisocyanate recently developed by The Dow Chemical Company. The physical properties of the elastomers are reported and discussed in comparison to similar elastomers prepared from commercially available aliphatic and aromatic isocyanates.

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“…This is consistent with observations of decreasing I 3 and an invariant free volume radius R upon clay loading for semicrystalline poly(m-xylene adipamide)/clay 25 and styrene-butadiene-rubber (SBR)/clay nanocomposites. The order of stiffness for various components of the nanocomposites can be stated as: nanoclay (B270 GPa) 64 > hard segment (B5 GPa) 65 > constrained soft segment > bulk soft segment (B5 MPa). 5.…”

Section: Resultsmentioning

confidence: 99%

Characterizing the nanoclay induced constrained amorphous region in model segmented polyurethane–urea/clay nanocomposites and its implications on gas barrier properties

Rath

Sudarshan

Bhavsar

et al. 2016

Phys. Chem. Chem. Phys.

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There has been an increasing recognition of the fact that purely geometric factors associated with clay platelet dispersion in a polymer matrix cannot adequately explain the barrier properties of polymer/clay nanocomposites. The objective of the present work is to understand the nanoclay induced structural changes in a polyurethane-urea matrix and clay dispersion at different length scales using segment-specific characterization techniques and implications of the same in gas barrier properties using He, N2 and CO2 as probe molecules. Wide angle X-ray diffraction (WAXD) and positron annihilation life time spectroscopy (PALS) studies revealed nanoclay induced alterations in the chain packing of the amorphous soft segments of the polyurethane matrix at a molecular scale of a few Angstroms. The hard segment organization and the phase morphology of the nanocomposites, spanning length scales of several nanometers, were investigated by small angle X-ray scattering (SAXS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Furthermore, the presence of a constrained amorphous region surrounding the nanoclay was confirmed from AFM, WAXD and PALS results. Several pertinent structural variables from the gas transport point of view were deduced from these characterization techniques to understand the effect of the barrier properties in tandem with the clay dispersion morphology.

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Theoretical modeling of the relationship between Young's modulus and formulation variables for segmented polyurethanes

Cited by 44 publications

References 62 publications

Revisiting thermoplastic polyurethane, from composition to morphology and properties

Revisiting thermoplastic polyurethane, from composition to morphology and properties

Polyurethane elastomers based on 1,3 and 1,4‐bis(isocyanatomethyl)cyclohexane

Characterizing the nanoclay induced constrained amorphous region in model segmented polyurethane–urea/clay nanocomposites and its implications on gas barrier properties

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