A Segmented Polyurethane Elastomer with Liquid Crystalline Hard Segments. 2. Rheological Study

1995 ◽  
Vol 28 (2) ◽  
pp. 512-516 ◽  
Author(s):  
Wolfgang Wedler ◽  
Weiming Tang ◽  
H. Henning Winter ◽  
William J. MacKnight ◽  
Richard J. Farris
Keyword(s):  
Liquid Crystalline ◽  
Polyurethane Elastomer ◽  
Segmented Polyurethane ◽  
Rheological Study ◽  
Hard Segments

Segmented Polyurethane Elastomers with Liquid Crystalline Hard Segments. 1. Synthesis and Phase Behavior

1994 ◽  
Vol 27 (10) ◽  
pp. 2814-2819 ◽  
Author(s):  
Weiming Tang ◽  
Richard J. Farris ◽  
William J. MacKnight ◽  
Claus D. Eisenbach
Keyword(s):  
Phase Behavior ◽  
Liquid Crystalline ◽  
Segmented Polyurethane ◽  
Polyurethane Elastomers ◽  
Hard Segments

scholarly journals Abrasive resistance of polyetherurethane ureas

2021 ◽  
Vol 2094 (4) ◽  
pp. 042077
Author(s):  
V Yu Senichev ◽  
E V Pogorel’tsev
Keyword(s):  
Experimental Data ◽  
Abrasion Resistance ◽  
Polymer Chains ◽  
Volumetric Wear ◽  
Segmented Polyurethane ◽  
Abrasive Resistance ◽  
Hard Segments ◽  
The Relationship

Abstract The relationship between the structure of the polymer chains and the abrasion resistance of segmented polyurethane ureas based on polyoxytetramethylene oligoether was studied. Experimental data were obtained for systems with the hard segments content above 39%. It was found that the function of the volumetric wear of polyurethane-urea samples on the content of hard segments had an extremum; at high contents of these segments (more than 35%), a further increase in this content lead to a deterioration in the abrasion resistance. The reasons for this effect can be associated with a sharp deterioration in the strength and strain properties of the studied elastomers when additional amounts of diisocyanate are introduced into the system, which can lead to the formation of excessive interchain bonds.

Time-Dependent Morphology Development in a Segmented Polyurethane with Monodisperse Hard Segments Based on 1,4-Phenylene Diisocyanate

2005 ◽  
Vol 38 (24) ◽  
pp. 10074-10079 ◽  
Author(s):  
Jignesh P. Sheth ◽  
Derek B. Klinedinst ◽  
Todd W. Pechar ◽  
Garth L. Wilkes ◽  
Emel Yilgor ◽  
...  
Keyword(s):  
Time Dependent ◽  
Segmented Polyurethane ◽  
Hard Segments ◽  
Morphology Development ◽  
Monodisperse Hard Segments

scholarly journals Structure and Methanical Properties of Segmented Polyurethane Elastomer

1970 ◽  
Vol 73 (7) ◽  
pp. 1541-1551 ◽  
Author(s):  
Ituro KIMURA ◽  
Hajime SUZUKI ◽  
Katsuo SAITO ◽  
Kotaro WATANABE ◽  
Hideaki ISHIHARA ◽  
...  
Keyword(s):  
Polyurethane Elastomer ◽  
Segmented Polyurethane

Polydimethylsiloxane-Based Polyurethanes: Phase-Separated Morphology and In Vitro Oxidative Biostability

2009 ◽  
Vol 62 (8) ◽  
pp. 794 ◽  
Author(s):  
Taeyi Choi ◽  
Jadwiga Weksler ◽  
Ajay Padsalgikar ◽  
Rebeca Hernéndez ◽  
James Runt
Keyword(s):  
Segmented Polyurethane ◽  
Two Phase ◽  
Dimethyl Siloxane ◽  
X Ray Scattering ◽  
Soft Segments ◽  
Hard Segments ◽  
Segmented Polyurethanes ◽  
Methylenediphenyl Diisocyanate ◽  
End Group

Three series of segmented polyurethane block copolymers were synthesized using 4,4′-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BDO) or 1,3-bis(4-hydroxybutyl)tetramethyl disiloxane (BHTD) as the hard segments, and soft segments composed of poly(dimethyl siloxane) (PDMS)-based and poly(hexamethylene oxide) (PHMO) macrodiols. Copolymers synthesized with the PDMS macrodiol and PDMS and PHMO macrodiol mixtures consist of three microphases: a PDMS phase, hard domains, and a mixed phase of PHMO (when present), PDMS ether end-group segments and some dissolved hard segments. Degrees of phase separation were characterized using small-angle X-ray scattering by applying a pseudo two-phase model, and the morphology resulting from unlike segment demixing was found to be closely related to the in vitro oxidative biostability of these segmented polyurethanes.

Tensile Strength of Polyurethane and other Elastomeric Block Copolymers

1976 ◽  
Vol 49 (1) ◽  
pp. 64-84 ◽  
Author(s):  
Thor L. Smith
Keyword(s):  
Dominant Factor ◽  
Domain Formation ◽  
Limited Information ◽  
Segmented Polyurethane ◽  
Polyurethane Elastomers ◽  
Type Size ◽  
Strain Induced Crystallization ◽  
Hard Segments ◽  
General Relations ◽  
Induced Crystallization

Abstract The discussion in this paper has been focused on the strength of Polyurethane elastomers, data on other materials being presented for comparison and to illustrate factors that affect strength. Although the literature on Polyurethane elastomers is voluminous, only in recent years has it been widely recognized that plastic domains exist in most polyurethane formulations of technological importance. Evidence for domain formation and aspects of domain morphology are discussed in recent reviews. The morphology of domains in segmented polyurethane elastomers is more complex than of those in triblock elastomers and has not been studied extensively, although progress is being made, indicated by the discussions in recent publications and references cited therein. In view of the complexities of fracture and the limited information on the morphology and time-dependent mechanical properties of polyurethane elastomers, only general relations between strength and chemical structure have thus far been established. On the other hand, useful correlations can be established by considering the type, size, and concentration of the hard segments and whether strain-induced crystallization is a dominant factor.

scholarly journals Mechano-responsive hydrogen-bonding array of thermoplastic polyurethane elastomer captures both strength and self-healing

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Youngho Eom ◽  
Seon-Mi Kim ◽  
Minkyung Lee ◽  
Hyeonyeol Jeon ◽  
Jaeduk Park ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Thermoplastic Polyurethane ◽  
Healing Process ◽  
Polyurethane Elastomer ◽  
Self Healing ◽  
Static Mode ◽  
Soft Segments ◽  
Hard Segments ◽  
Thermoplastic Polyurethane Elastomer ◽  
Dynamic Exchange

AbstractSelf-repairable materials strive to emulate curable and resilient biological tissue; however, their performance is currently insufficient for commercialization purposes because mending and toughening are mutually exclusive. Herein, we report a carbonate-type thermoplastic polyurethane elastomer that self-heals at 35 °C and exhibits a tensile strength of 43 MPa; this elastomer is as strong as the soles used in footwear. Distinctively, it has abundant carbonyl groups in soft-segments and is fully amorphous with negligible phase separation due to poor hard-segment stacking. It operates in dual mechano-responsive mode through a reversible disorder-to-order transition of its hydrogen-bonding array; it heals when static and toughens when dynamic. In static mode, non-crystalline hard segments promote the dynamic exchange of disordered carbonyl hydrogen-bonds for self-healing. The amorphous phase forms stiff crystals when stretched through a transition that orders inter-chain hydrogen bonding. The phase and strain fully return to the pre-stressed state after release to repeat the healing process.

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