Enhancing polyurethane properties via soft segment crystallization

Sonnenschein, Mark F.; Lysenko, Zenon; Brune, Douglas A.; Wendt, Benjamin L.; Schrock, Alan K.

doi:10.1016/j.polymer.2005.08.006

Cited by 91 publications

(67 citation statements)

References 27 publications

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“…Similar behavior has also been reported by Yen and Cheng upon increasing the crystalline poly(butylene adipate glycol) soft segment content in segmented polyurethanes [26]. Most recently, Sonnenschein et al probed the enhancement of material properties using semicrystalline polyester diols as soft segments in low hard segment content polyurethanes, concluding that crystalline soft segments reinforce the hard phase according to a continuous reinforcement model [27].…”

Section: Introductionsupporting

confidence: 69%

Effect of the degree of soft and hard segment ordering on the morphology and mechanical behavior of semicrystalline segmented polyurethanes

Korley

Pate

Thomas

et al. 2006

Polymer

321

214

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Section: Introductionsupporting

confidence: 69%

Effect of the degree of soft and hard segment ordering on the morphology and mechanical behavior of semicrystalline segmented polyurethanes

Korley

Pate

Thomas

et al. 2006

Polymer

321

214

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“…In TPUs the amorphous layers are formed by soft domains, and the hard domains are not completely crystalline, but only quasi-crystalline. [ 41 ] This conclusion is drawn because the melt enthalpies of TPUs are generally low. [41][42][43] Figure 3 presents DSC data of the raw pellets and of the injection molded materials.…”

Section: Waxs Patternsmentioning

confidence: 99%

“…[ 41 ] This conclusion is drawn because the melt enthalpies of TPUs are generally low. [41][42][43] Figure 3 presents DSC data of the raw pellets and of the injection molded materials. The part between 50 and 280 ° C is displayed.…”

Section: Waxs Patternsmentioning

confidence: 99%

Structure and Mechanical Properties of an Injection‐Molded Thermoplastic Polyurethane as a Function of Melt Temperature

Stribeck

Zeinolebadi

Sari

et al. 2011

Macro Chemistry & Physics

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Thermoplastic polyurethanes (TPUs) molded at 205, 215, and 235 ° C are monitored by SAXS and WAXS during straining. A non-affi ne nanostructure deformation and related evolution mechanisms are found. DSC and microscopy are applied. DSC shows two melting endotherms. The results indicate that melts kept below the second peak stay phase-separated. The orientation parameter f ( ε ) and d f /d ε from WAXS are related to chain orientation mechanisms (strain ε ). SAXS shows hard domains that are only correlated to a next neighbor ("sandwich"). Thick sandwiches lengthen more than thin ones. Thin-layer sandwiches feature a strain limit. Some are converted into thick-layer sandwiches. Two materials have tough hard domains. Material processed at 235 ° C is soft and contains weak hard domains that fail for ε > 0.75. of the material. Block copolymers synthesized by living polymerization are characterized by uniform block lengths. Processing of such compounds may result in lattice-like nanostructures or even in photonic crystals, in which the soft and the hard blocks reside completely in different domains. This is different with thermoplastic polyurethanes (TPU). Along with their chains a mixed sequence of soft segments and hard segments is found. Thus, even optimum process control only leads to domains of very diverse shape and size, the arrangement of which can rarely lead to lattice-like correlation. Moreover, soft domains may contain several hard segments. Consequently, the chemistry [ 1 ] and the processing conditions [2][3][4][5] defi ne the nanostructure that, in turn, determines the material's mechanical properties. The hard domains form physical cross-links and make the material behave rubber elastic. Because the hard domains are permanent only to a fi rst approximation, the stressstrain behavior of TPUs is subject to "strong hysteresis, time dependence and cyclic softening". [ 6 ] Thus maturing or aging may become a problem, if longer time elapses between investigations with different methods, because in this case the results may not be combined.

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“…[1][2][3][4] They are multiblock copolymers with alternating soft segments (SSs) and hard segments (HSs). 7 The characteristics of PU copolymers can be controlled and adjusted by different natures of SS and HS. 7 The characteristics of PU copolymers can be controlled and adjusted by different natures of SS and HS.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of in vitro cytotoxicity and properties of polydimethylsiloxane‐based polyurethane/crystalline nanocellulose bionanocomposites

Khadivi

Salami‐Kalajahi

Roghani‐Mamaqani

2019

J Biomedical Materials Res

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Polydimethylsiloxane‐based polyurethane (PU)/crystalline nanocellulose (CNC) bionanocomposites were produced via in situ prepolymer approach. Also, hexamethylene diisocyanate as aliphatic diisocyanate monomer and 1,4‐butanediol as aliphatic chain extender were used. CNC was incorporated into PU matrix to prepare different PU/CNC bionanocomposites. Effect of CNC content on the properties of the bionanocomposites such as thermal, thermophysical, microstructure, and in vitro cytotoxicity was investigated. According to the results, incorporating CNCs into PU matrix significantly affected the hydrogen bonding between different microstructures of matrix. Adding different amounts of CNCs affected the thermal and thermophysical properties of bionanocomposites. Also, higher amounts of CNCs resulted in lower crystallization of hard segment. Neat PU matrix showed a moderate cytotoxicity behavior against human fibroblast cells. However, incorporating CNCs significantly improved the cytotoxicity behavior of bionanocomposites where by addition of 2 wt % of CNCs, cell viability increased to 90–100%. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1771–1778, 2019.

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Enhancing polyurethane properties via soft segment crystallization

Cited by 91 publications

References 27 publications

Effect of the degree of soft and hard segment ordering on the morphology and mechanical behavior of semicrystalline segmented polyurethanes

Effect of the degree of soft and hard segment ordering on the morphology and mechanical behavior of semicrystalline segmented polyurethanes

Structure and Mechanical Properties of an Injection‐Molded Thermoplastic Polyurethane as a Function of Melt Temperature

Evaluation of in vitro cytotoxicity and properties of polydimethylsiloxane‐based polyurethane/crystalline nanocellulose bionanocomposites

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