Millable Polyurethane Elastomers

Hepburn, C.

doi:10.1007/978-94-011-2924-4_7

Cited by 355 publications

(547 citation statements)

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“…25, 26 The hard segments act as physical crosslinks, and therefore the mechanical properties as well as the transport of small molecules through these materials depend on the ratio of hard-to-soft phase, i.e., the ratio of chain extender to polyol and the molecular weight of the latter. [27][28][29][30] While the exact chemical compositions of the three commercial TPUs used here are not known, the mechanical data ( Figure S6, tensile storage moduli E′ at 296 K are around 700, 25, and 5 MPa for Texin 270, Texin 285, and Tecoflex, respectively, cf. also the mechanical data provided by the manufacturers) 31 prepared by casting DMF solutions of the components and subsequent drying, in a manner that was identical to the processing of EO-EPI films.…”

Section: Resultsmentioning

confidence: 99%

Influence of Temperature on Low-Power Upconversion in Rubbery Polymer Blends

et al. 2009

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Abstract:The upconverting properties of a dye cocktail composed of palladium(II) octaethylporphyrin (PdOEP, triplet sensitizer) and 9,10-diphenylanthracene (DPA, triplet acceptor/annihilator) were investigated as a function of temperature in several low glass transition temperature (T g ) polymer hosts including an ethyleneoxide-epichlorohydrin copolymer (EO-EPI) and the polyurethanes Texin 270, Texin 285, and Tecoflex EG-80A. Selective excitation of PdOEP at 544 nm in the presence of DPA in these materials resulted in anti-Stokes blue emission from DPA, a consequence of sensitized triplet-triplet annihilation (TTA) photochemistry, confirmed by the quadratic dependence of the upconverted fluorescence intensity with respect to incident light power. The upconversion process was completely suppressed by cooling a PdOEP/DPA blend film to below the T g of the respective polymer. However, the blue emission was clearly visible by the naked eye upon heating these films to room temperature (290 K). Subsequently, the upconverted emission intensity increased with increasing temperature and was found to be completely reversible upon several heating and cooling cycles provided the temperature remained below 400 K. Heating samples above this temperature resulted in unrecoverable failure of the material to produce upconverted photons. The phosphorescence intensity decay of PdOEP in the polymer host, Tecoflex EG-80A, adequately fits to a sum of two exponential functions as well as the Kohlrausch-Williams-Watts (KWW) stretched exponential model. Increasing the temperature of the film increases the complexity and heterogeneity of the system as evidenced by the lower values obtained from the KWW model as the temperature increases.

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Section: Resultsmentioning

confidence: 99%

Influence of Temperature on Low-Power Upconversion in Rubbery Polymer Blends

et al. 2009

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“…A damping peak centered at K78 8C occurs due to the SS glass transition. An increase in tan d values is noted above 200 8C due to the softening of the hard phase and possible onset of degradation of the material since it is known [18] that both urethane and urea linkages are not highly stable for long periods in the range of 200 8C. The DMA behavior of the PTMO based highly branched analog, T2-H is also presented in Fig.…”

Section: Dynamic Mechanical Analysismentioning

confidence: 91%

A comparative study of the structure–property behavior of highly branched segmented poly(urethane urea) copolymers and their linear analogs

Sheth

Ünal

Yılgör

et al. 2005

Polymer

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“…It is one of the most versatile materials for applications that demand high flexibility and elasticity [8,9]. However, this polymer shows low mechanical strength and poor thermal stability hampering its use in high-temperature applications.…”

Section: Introductionmentioning

confidence: 99%

The effect of ultra-thin graphite on the morphology and physical properties of thermoplastic polyurethane elastomer composites

Menes

Cano

Benedito

et al. 2012

Composites Science and Technology

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Composites of thermoplastic polyurethane (TPU) and ultra-thin graphite (UTG) with concentrations ranging from 0.5 to 3 wt% were prepared using a solution compounding strategy. Substantial reinforcing effects with increased loadings are achieved. Compared to neat TPU, values for storage modulus and shear viscosity are enhanced by 300 % and 150 %, respectively, for UTG concentrations of 3 wt%. Additionally, an enhancement of thermal properties is accomplished. The crystallization temperature and thermal stability increased by 30 ºC and 10 ºC, respectively, compared to neat TPU. Controlling the oxidation degree, thus offers further possibilities to obtain composites with tailored properties. The presented approach is straightforward, leads to homogeneous TPU-UTG composites with improved materials properties and is especially suitable for commercial UTG materials and further up-scaled production.

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Millable Polyurethane Elastomers

Cited by 355 publications

References 0 publications

Influence of Temperature on Low-Power Upconversion in Rubbery Polymer Blends

Influence of Temperature on Low-Power Upconversion in Rubbery Polymer Blends

A comparative study of the structure–property behavior of highly branched segmented poly(urethane urea) copolymers and their linear analogs

The effect of ultra-thin graphite on the morphology and physical properties of thermoplastic polyurethane elastomer composites

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