Explaining the abnormally high flow activation energy of thermoplastic polyurethanes

Qi-wei, LU; Hernández-Hernández, María Elena; Macosko, Christopher W.

doi:10.1016/s0032-3861(03)00223-4

Cited by 49 publications

(45 citation statements)

References 14 publications

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“…They revealed that the temperature dependence of the zero shear viscosity was affected not only by the molecular mobility but also by the change in molecular weight due to urethane exchange reaction. Lu et al [15] used three different apparatuses, which were a dynamic shear, a capillary rheometry and an instrumented batch mixer to investigate the effect of degradation during TPU processing on the melt viscosity and reported the apparent activation energy of flow (E a ) and true activation energy of flow (E h ) were 328 and 144 kJ/mol, respectively. Their equation to calculate the contribution of flow and the degradation reaction of TPU to overall activation energy was as follows: E a ¼ E h þ 1.7 Â DH deg .…”

Section: Introductionmentioning

confidence: 99%

Effects of aggregation structure on rheological properties of thermoplastic polyurethanes

Yamasaki

Nishiguchi

Kojio

et al. 2007

Polymer

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Section: Introductionmentioning

confidence: 99%

Effects of aggregation structure on rheological properties of thermoplastic polyurethanes

Yamasaki

Nishiguchi

Kojio

et al. 2007

Polymer

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“…The isocyanate (-N=C=O) and hydroxyl (-OH) groups react forming the urethane group [25,26]. Two general methods are very common for the production of PU/POSS hybrid systems: melt blending and chemical synthesis.…”

Section: Polyurethane/poss Nanocompositessynthesis and Processingmentioning

confidence: 99%

The influence of POSS nanoparticles on selected thermal properties of polyurethane-based hybrids

Pielichowski

Raftopoulos

Pielichowski

2017

J Therm Anal Calorim

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Organic-inorganic hybrid materials, prepared via chemical synthesis route or physical blending of functionalized nanofillers within polymer matrix, have gained an increased attention in the recent years. Polyhedral oligomeric silsesquioxane (POSS) nanoparticles, due to their nanometer size and functionalization possibilities, are applied as effective modifiersboth chemical and physical, for polymer matrices, including polyurethanes (PU). In this work, we describe the synthesis and processing of polyurethane/POSS hybrid nanocomposites and discuss the influence of POSS moieties on the thermal properties of PU matrices. Glass transition, the crystallinity of the soft phase, as well as the order-disorder transitions are affected by the incorporation of POSS in the polyurethane structure. Direct polymer-POSS interaction, or -indirect-due to the suppression or enhancement of microphase separation by the POSS moieties are discussed in terms of topology of the polymeric structure with the key role of POSS functionalization.

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“…In the past two decades it has mostly replaced acrylic paints (Lu 2003). For this paint, the binder is polyurethane (C3H7NO2) and the pigment is Chromium (III) oxide (Cr2O3).…”

Section: Chemical Reactionmentioning

confidence: 99%

Multicomponent Gas-Particle Flow and Heat/Mass Transfer Induced by a Localized Laser Irradiation on a Urethane-Coated Stainless Steel Substrate

Afrin¹,

Chen²,

Zhang³

et al. 2016

Frontiers in Heat and Mass Transfer

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A three-dimensional numerical simulation is conducted for a complex process in a laser-material system, which involves heat and mass transfer in a compressible gaseous phase and chemical reaction during laser irradiation on a urethane paint coated on a stainless steel substrate. A finite volume method (FVM) with a co-located grid mesh that discretizes the entire computational domain is employed to simulate the heating process. The results show that when the top surface of the paint reaches a threshold temperature of 560 K, the polyurethane starts to decompose through chemical reaction. As a result, combustion products CO2, H2O and NO2 are produced and chromium (III) oxide, which serves as pigment in the paint, is ejected as solid parcels from the paint into the gaseous domain. Variations of temperature, density and velocity at the center of the laser irradiation spot, and the concentrations of reaction reactant/products in the gaseous phase are presented and discussed, by comparing six scenarios with different laser powers ranging from 2.5 kW to 15 kW with an increment of 2.5 kW.

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Explaining the abnormally high flow activation energy of thermoplastic polyurethanes

Cited by 49 publications

References 14 publications

Effects of aggregation structure on rheological properties of thermoplastic polyurethanes

Effects of aggregation structure on rheological properties of thermoplastic polyurethanes

The influence of POSS nanoparticles on selected thermal properties of polyurethane-based hybrids

Multicomponent Gas-Particle Flow and Heat/Mass Transfer Induced by a Localized Laser Irradiation on a Urethane-Coated Stainless Steel Substrate

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