Property-Structure Relationships in Polyurethanes

Hepburn, C.

doi:10.1007/978-94-011-2924-4_3

Cited by 9 publications

(13 citation statements)

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“…Reference source not found. ), for which the Tg's are below room temperature (Tg = −70 °C to −30 °C), and are low-melting-point solids or liquids [31,32]. Mixed copolymer diols containing polyethers and/or polyesters have also been used to form the SS [23].…”

Section: Macrodiolsmentioning

confidence: 99%

“…This is because urethane NH-ester carbonyl hydrogen bonds are stronger than urethane NH-ether oxygen bonds, as the ester carbonyl group has higher polarity [23,31]. With the weaker interchain forces, polyether PUs have inferior physical properties [51,52], although they possess a superior hydrolytic stability [31,[52][53][54]. The Tg values of PEsUs are also higher than those of PEtUs [52].…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…The molecular mass (M) of macrodiols has a significant impact on the degree of phase separation and properties (including Tg) of PU elastomers [23,31].…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…During PU synthesis, diisocyanates are responsible for chain extension and the formation of urethane linkages or a variety of crosslinks by further reaction [24]. The HSs are usually formed by the reaction of a diisocyanate with a glycol or a diamine, although occasionally other ChExs are employed [31]. The properties of HSs determine the interchain interactions in the elastomers to a large extent and so determine the network structure in these materials [31].…”

Section: Isocyanatesmentioning

confidence: 99%

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Degradation and stabilization of polyurethane elastomers

Xie

Zhang

Bryant

et al. 2019

Progress in Polymer Science

415

301

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Section: Macrodiolsmentioning

confidence: 99%

Section: Accepted Manuscriptmentioning

confidence: 99%

“…The molecular mass (M) of macrodiols has a significant impact on the degree of phase separation and properties (including Tg) of PU elastomers [23,31].…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Section: Isocyanatesmentioning

confidence: 99%

See 2 more Smart Citations

Degradation and stabilization of polyurethane elastomers

Xie

Zhang

Bryant

et al. 2019

Progress in Polymer Science

415

301

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“…Depending on the block composition, segmented PU can exhibit properties ranging from those of soft elastomers to hard plastics while retaining the processing characteristics of thermoplastics. The soft blocks are typically long, flexible molecules with a glass transition temperature (T g ) below room temperature whereas the hard blocks, composed of diisocyanate condensed with small molecule diol, have a T g above room temperature [56,57]. Segmented PUs typically exhibit excellent nanophase separation due to the incompatibility of soft and hard domains.…”

Section: Introductionmentioning

confidence: 99%

Tuning nanophase separation behavior in segmented polyhydroxyurethane via judicious choice of soft segment

Beniah

Uno

Lan

et al. 2017

Polymer

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based soft segments, with divinyl benzene dicyclocarbonate and Dytek-A as hard segment and chain extender, respectively. These NIPU polymers were characterized by small-angle X-ray scattering (SAXS), atomic force microscopy (AFM), dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and tensile testing. SAXS reveals that the NIPUs with 30-40 wt% hard segment are nanophase separated with interdomain spacings of 9-16 nm. DMA reveals that PTMO-based PHUs have broad interphases with a range of local compositions and glass transition temperatures (T g s), with tan δ ≥ 0.3 over temperature ranges exceeding 70 °C in breadth. In contrast, PBN-based PHUs have sharper interphases, evidenced by narrow tan δ peaks near soft-segment and hard-segment T g s as well as by DSC and AFM data. FTIR shows that the ratio of hydrogen-bonded carbonyl to free carbonyl

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Adhesion properties and phase separation behavior of glycidyl‐terminated polyurethanes

Hsia

Chen‐Chi

Chen³

1994

Angew. Makromol. Chem.

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2,3-Epoxy-l -propano1 has been introduced into isocyanate-terminated polyurethane to form glycidyl-terminated polyurethane resins. A series of glycidyl-terminated polyurethanes based on hydroxyterminated poly(oxypropy1ene) (poly(oxypropylene)glycol, PPG), toluene diisocyanate (TDI), and 1 ,4-butanediol (BD) was synthesized with various PPG soft segment lengths (MW 700, 1000 and 2000) and soft segment concentrations (30, 50 and 70 wt.-Vo). The effect of glycidyl-terminated polyurethane on the adhesion properties and the phase separation were investigated. The adhesion properties at liquid nitrogen temperature coincide with the phenomenon observed in the phase separation behavior of polyurethane. Differential scanning calorimetry (DSC) and infrared technique (IR) were used to assess the phase separation content. The enthalpy jump at the glass transition temperature (AC,) and the unique spectroscopic features in the N-H and C=O stretching regions were applied to characterize the phase separation behavior. It was found that the modified resins do not only show superior adhesion at liquid nitrogen temperature but also exhibit some unique properties, e. g., room temperature curing and good storage stability. ZUSAMMENFASSUNG:Die Klebeeigenschaften und das Phasentrennungsverhalten von Polyurethanen aus ,,weichen" Poly(oxypropy1en)-Einheiten (PPG) und ,,harten" Segmenten aus Toluoldiisocyanat (TDI) und 1,4-Butandiol (BD) wurden untersucht. Die Lange der PPG-Weichsegmente (PPG mit MW 700, 1 OOO bzw. 2000) sowie deren Konzentration (30, 50 and 70 Gew.-Vo) wurden variiert. Die Isocyanat-Endgruppen dieser PU-Harze wurden mit 2,3-Epoxy-l-propanol zu Glycidyl-Endgruppen umgesetzt. Die Klebeeigenschaften bei der Temperatur flussigen Stickstoffs folgen dem Phasentrennungsverhalten der Polyurethane. Die Phasentrennung wurde mit DSC-(Enthalpiesprung bei der Glasternperatur) und IR-Messungen (Veranderungen im Bereich der N-H-und C=O-Streckschwingungen) untersucht. Die rnodifizierten PU-Harze weisen neben verbesserter Haftung bei tiefen Temperaturen auch gute Lagerungseigenschaften sowie die Fahigkeit der Hartung bei Raumtemperatur auf.

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Property-Structure Relationships in Polyurethanes

Cited by 9 publications

References 0 publications

Degradation and stabilization of polyurethane elastomers

Degradation and stabilization of polyurethane elastomers

Tuning nanophase separation behavior in segmented polyhydroxyurethane via judicious choice of soft segment

Adhesion properties and phase separation behavior of glycidyl‐terminated polyurethanes

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