Abstract. The microstructure and macroscopic properties of thermoplastic polyurethanes (TPUs) are significantly affected by their microphase separation. It is …
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Semantic Scholar extracted view of "Visualization and quantification of microphase separation in thermoplastic polyurethanes under different hard segment contents and its effect on the mechanical properties" by Miaoming Huang et al. DOI: 10.1016/j.polymertesting.2024.108329
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In addition, increased SS/HS incompatibility led to greater microphase separation and consequently, an increase in the magnitude of the storage modulus plateau. The larger HS mass also increased the temperature at which HS melting occurred, effectively broadening the storage modulus plateau.
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In this work, we have studied effects of the polydispersity on the microphase separation in thin films of lamellar forming di-block copolymers using self-consistent field theory (SCFT) and neutron ...
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The magnitude of the dynamic storage modulus is affected by the physical microphase separation and irreversible crosslinking network, with the latter spontaneously forming …
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The latter is expected to be especially important in the dynamics of elastomeric block copolymers whose blocks usually have widely separated Tg''s. 1. Introduction. Polyurethanes are (AB)n type multiblock copolymers composed of "hard" and "soft" segments that microphase-separate due to thermodynamic incompatibility.
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This result suggests that the observed decrease in storage modulus versus temperature is related to phase mixing and to the dissociation of secondary bonds between the end-groups of the polymers [8]. Isothermal frequency sweeps were also performed and time-temperature superposition used to produce master curves presented …
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The results of different microphase separation states and different microscopic Young''s modulus obtained by AFM are expected to be reflected in the macroscopic mechanical properties of TPUs. Therefore, the typical stress-strain curves and mechanical properties of TPUs were shown in Fig. 8 .
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It was demonstrated that uniformly distributed spherical microphase separation had a profound effect on the improvement of tensile modulus. Based on the morphology characterizations by AFM, the verification of …
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Download Citation | The effect of inorganic particles on microphase separation of polyether polyurethanes | Polyurethanes(PUs) developed from polytetramethylene glycol (PTMG), toluene 2, 4 ...
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Abstract. This paper describes the influence of mixed poly (tetramethylene oxide) (PTMO) soft segments on microphase separation and morphology, hydrogen bonding, and polymer transitions for a series of alternating polyurea copolymers prepared from a single modified diphenylmethane diisocyanate. The fraction of two PTMO soft …
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authors demonstrated a 10-fold decrease in the storage modulus in the temperature range corresponding to microphase mixing. The focus of their study was the microphase mixing of the PU and not rheological characterization; in any case, due to the high hard- T
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Remarkably, the sequence of A and B blocks significantly affects the microphase separation process, resulting in distinct morphologies. The effect can be …
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The storage modulus was independent of temperature and the loss modulus slightly increased at temperature above 75 C, revealing its stability at elevated temperature. Also, …
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The present work investigates the combined effect of the addition of graphene nanoplatelets (GNPs) to the thermoplastic polyurethane copolymer (TPU) and thermal treatment evaluation of the resultant TPU/GNP nanocomposite. Thus, this factor can be evaluated through a variety of dynamic mechanical and thermal measurements. The …
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Microphase Separation and Rheological Properties of Polyurethane Melts. 3. Effect of Block Incompatibility on the Viscoelastic Properties. Macromolecules 2000, 33 (2), 395-403. DOI: 10.1021/ma9908189. Stefan Oprea.
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Polyurethanes1,2 (PUs) are an important class of thermoplastic elastomer with wide applications as coat-ings, binder resins, fibers, and high-performance elas-tomeric products. Typical PU elastomers are multiblock copolymers comprised of alternating "soft" polyether or polyester segments and "hard" polyurethane segments.
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Microphase separation in the form of dense protein domains was observed for mixtures with microgels even at very low -car concentrations (0.5 g/L). Gelation of -car was induced by cooling in the ...
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Here elastic microphase separation is used to fabricate bicontinuous materials with a homogeneous microstructure, with feature sizes tuned by the matrix …
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Furthermore, considering that hydrogen bonding of PU may soften above 100 C, the storage modulus, loss modulus, and Tan(delta) of PF-PU11-10 from room temperature to 200 C were determined (Fig. 4 f).
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The microphase separation behavior of polyurethane (PU) strongly affects its mechanical, thermal, electrical, and other functional properties. Adding fillers to change the degree of...
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change of anion shows great effect on the tensile modulus of phase-separated ionogels (10 7 ... stiffness-changing polymer networks by glass transition mediated microphase separation. Nat Commun ...
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polymer:effect of the steric hindrance of the ureido-pyrimidone on their viscoelasticity† ... More importantly, with the degree of the micro-phase separation increased, the storage modulus or the elasticity modulus increased exponentially and the T m and the loss ...
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Velankar S, Cooper SL (2000) Microphase separation and rheological properties of polyurethane melts. 2. Effect of block incompatibility on the microstructure. Macromolecules 33:382–394 Article CAS Google Scholar
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Crystallization from a homogeneous melt for block copolymers containing crystalline blocks and amorphous blocks can also induce microphase separation by the expulsion of amorphous blocks [13], [14]. More information about structure, properties and theory of well-defined di- or tri-block copolymers can be found elsewhere [2], [15] .
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This study investigates the effects of scCO 2 assisted extrusion on thermal, mechanical, electrical, and morphological properties of microphase separated …
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The structure–morphology–property relationship of thermoplastic polyurethanes and polyureas was reviewed. The effect of hard segment structure and chemistry, and the hydrogen bonding on the morphology and properties of polyurethanes elastomers was presented. Special attention was made on polyureas with strong …
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Microphase separation of a quadruple hydrogen bonding supramolecular polymer: Effect of the steric hindrance of the ureido-pyrimidone on their viscoelasticity March 2019 RSC Advances 9(16):8905-8911
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In the tensile testing, Young''s modulus of the PUEs decreased and increased with an increase in the methylene number, which can be explained by the degree of microphase separation.
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To characterize the degree of microphase separation, the effect of hard-segment crystallization needs to be deducted, which can be obtained from Eq. (8) . (8) Q = ∫ 0 ∞ q 2 I ( q ) V I e ( q ) d q ∼ χ c ∅ H ∅ S ( ρ H − ρ S ) 2 where ∅ H and ∅ S are the fraction of hard and soft amorphous phase, respectively; ρ H and ρ S refer the electron cloud …
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The effect of crystallization on the glassy microphase development is studied on the highest titanium-containing glass (SBNT14.6) and the results are compared with titanium-free glass (SBNT0). Data …
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Effect of diacylhydrazine as chain extender on microphase separation and performance of energetic polyurethane e-Polymers ( IF 2.025) Pub Date : 2020-09-02, DOI: 10.1515/epoly-2020-0052 Yang Gao, Jie Lv, Licheng Liu, Yingfeng Yu
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