Polyurethanes with Narrow‐ and Polydisperse Hard Segment Distributions

De, Debasish; Gaymans, R.J.

doi:10.1002/mame.200800147

Cited by 6 publications

(13 citation statements)

References 17 publications

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“…The absence of a lowering of the CS with increase in SS length must have been due to the TDI groups in the SS. A similar effect was observed with MDI groups in the PTMO in the same concentration range 18. However, the CS values were with TDI lower than with MDI (21%), but also the moduli were lower.…”

Section: Resultssupporting

confidence: 78%

“…Also the heats of fusion increased a bit. This small effect is comparable to the MDI extended PTMO 2000 based polyurethane and is due to the longer SS 18. The melting temperatures of the HS decreased with increase in the SS length.…”

Section: Resultsmentioning

confidence: 56%

“…Curved ribbons compared to linear ribbons are expected not to be as effective in reinforcing the matrix. In MDI‐6T6‐MDI HS the crystalline ribbons were more extended 18. The TDI units next to the 6T6 units thus seem to induce curved/spiral crystallite morphologies.…”

Section: Resultsmentioning

confidence: 96%

“…Viscoelastic deformation of PUUA was characterized by stress relaxation measurement. Two stress relaxation regions were observed (a) first 100 s and (b) at longer times 18, 23. In the first 100 s the sample showed a large drop in stress.…”

Section: Resultsmentioning

confidence: 98%

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Thermoplastic Polyurethanes with TDI‐Based Monodisperse Hard Segments

Gaymans

2009

Macro Materials & Eng

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Polyurethanes with PTMO soft segments and toluene diisocyanate diamide as urethane segment were studied. The toluene diisocyanate diamide urethane segment was monodisperse in length. The soft segment length was changed by extending PTMO with TDI units to a soft segment length varying from 2 250 to 6 500 g · mol−1. Studied were the structure, the morphology, the thermal and thermal mechanical behavior, the elastic behavior, and the tensile properties. The monodisperse diisocyanate diamide urethane segments had a high crystallinity and the crystallites showed a curved nano‐ribbon morphology. Extending the PTMO units with TDI groups increased Tg and Tm of PTMO slightly, and the elastic properties at room temperature were not affected.magnified image

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Section: Resultssupporting

confidence: 78%

Section: Resultsmentioning

confidence: 56%

Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 98%

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Thermoplastic Polyurethanes with TDI‐Based Monodisperse Hard Segments

Gaymans

2009

Macro Materials & Eng

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“…[10][11][12][13][14] TPUs with a narrow dispersity in molecular weight generally show a higher and preferred elastic modulus, a less temperature-dependent modulus between the T g of the soft segment and the T m of the hard segments. [15][16][17][18][19] Electronic supplementary material The online version of this article (doi:10.1007/s10965-015-0812-5) contains supplementary material, which is available to authorized users.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and evaluation of alkoxylated-ether diols of hydroquinone with different chain-lengths as extenders in segmented polyurethanes

et al. 2015

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Two symmetrical alkoxylated-ether diols of hydroquinones (HQ), 1,4-bis(2-hydroxyethoxy)benzene (HQEE) and 1,4-bis(2-hydroxypropoxy)benzene (HQPP), were synthesized from HQ and cyclic carbonates. Another asymmetric alkoxylated-ether diols of HQ, 1-(4-(2-hydroxyethoxy)-phenoxy)propan-2-ol (HQEP), was prepared from bisphenol-A through 4-isopropenyl phenol (4-IPP). By taking advantage of the reactivity differences between primary and secondary alcohol in HQEP toward isocyanate group, two more longchained and low-dispersed extenders, bis(2-(4-(2-hydroxypropoxy)phenoxy)ethyl) hexane-1,6-diyldicarbamate (HQU2) and bis(2-(4-(2-hydroxypropoxy)phenoxy)ethyl) 6,6′-carbonylbis(azanediyl)bis(hexane-6,1-diyl) dicarbamate (HQU3) were prepared by selective reaction between HQEP with 1,6-hexamethylene diisocyanate (HDI). Segmented polyurethanes (PUs) based on HDI, polyethylene-butylene-adipate diol (PEBA-diol), and all five synthesized hard-segment diols as the hard segment ingredients were prepared for comparison. PUs prepared from HQU2 or HQU3 exhibited much balanced properties than those based on HQEE and HQPP. Especially, PU based on HQU3 exhibits highly segregated morphology as well as good physical performances showing good elongation (362 %), high modulus at rubbery plateau regions (115 MPa at E' 25°C ), high relative tensile strength (7.6 MPa) and thermal stability (306°C). The result confirms that long-chain extenders with narrow dispersity in molecular weight when used as the hard-segment component can offer substantial advantages in physical properties for PU over those made similarly from discrete and shorter chains counterparts.

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Well‐defined Biobased Segmented Polyureas Synthesis via a TBD‐catalyzed Isocyanate‐free Route

Tang

Mulder

Noordover

et al. 2011

Macromol. Rapid Commun.

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Via an isocyanate-free route, a series of segmented polyureas (PUs) were synthesized from (potentially) renewable resources. To the best of our knowledge, the present work shows for the first time that the organic superbase guanidine 1,5,7-triazabicyclododecene (TBD) which was originally developed as a catalyst for the ring-opening polymerization of lactones, lactides or cyclic carbonates, is also a promising catalyst for the transurethanization between dicarbamates and diamino-terminated poly(propylene glycol) (PPGda) providing PUs via an isocyanate-free strategy. The renewable segmented PUs contain monodisperse hard segments (HSs). This well-defined structure was verified by the DMTA plots of the PUs, showing a sharp glass transition, a sharp flow transition and a flat rubbery plateau. The flow and maximum use temperature (Tfl ) of the PUs increases with the increasing number of urea groups in the corresponding dicarbamates. In addition, at constant HS length, the length of the soft-segment (SS) can be changed to adjust the properties of the PU materials, enabling their application as adhesives, soft elastomers, or rigid plastics.

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Polyurethanes with Narrow‐ and Polydisperse Hard Segment Distributions

Cited by 6 publications

References 17 publications

Thermoplastic Polyurethanes with TDI‐Based Monodisperse Hard Segments

Thermoplastic Polyurethanes with TDI‐Based Monodisperse Hard Segments

Synthesis and evaluation of alkoxylated-ether diols of hydroquinone with different chain-lengths as extenders in segmented polyurethanes

Well‐defined Biobased Segmented Polyureas Synthesis via a TBD‐catalyzed Isocyanate‐free Route

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