The Kinetics of the Thermal Decomposition of Thermoplastic Polyurethane Elastomers under Thermoplastic Processing Conditions

Endres, Wolfgang; Lechner, M. D.; Steinberger, Rolf

doi:10.1002/mame.200390050

Cited by 20 publications

(17 citation statements)

References 12 publications

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“…The obvious candidate for these changes in rheological behavior is a variation of molecular weight upon the first heating/cooling cycle. In fact, it has been observed that at high temperatures, the molecular weight of TPUs decreases due to the dissociative reaction of the urethane bonds, whereas it is also well-documented that at lower temperatures, the molecular weight tends to build back up due to formation of new urethane bonds [2,6,[17][18][19]. Table 2 presents just such an evolution in molecular weight upon heating and cooling of the TPUs used in this study.…”

Section: Shear Rheology and Gpcmentioning

confidence: 75%

The influence of thermo-mechanical history on structure development of elastomeric and amorphous glass thermoplastic polyurethanes

Silva

Meltzer²,

Liu

et al. 2013

Polym Eng Sci

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In this work, the effect of processing and subsequent thermal treatment on the rheological behavior and microstructure aggregation of two different types of thermoplastic polyurethanes (TPUs) are investigated. Elastomeric TPUs, which are segmented block copolymers composed of alternating soft and hard segments, and amorphous glassy TPU, predominantly composed of hard segments, were subjected to heating/cooling cycles after extrusion. All materials show rheological hystereses after the first thermal cycle; in amorphous glassy TPUs, there is an increase in dynamic moduli but the loss tangent remains unchanged, whereas in the elastomeric TPUs, there are both decreases in dynamic moduli and hystereses in the loss tangent. The changes in molecular weight during the thermal cycle were tracked by gel permeation chromatography and shown not to be responsible for the rheological hystereses. For both elastomeric and amorphous glassy TPUs, fourier transform infrared spectroscopy results indicate that an increase in dynamic moduli, especially G′, is associated with a higher degree of hydrogen bonding. These results combined with X‐ray data indicate that upon extrusion the elastomeric TPUs form a network in which hydrogen bonding plays an important role. This structure can be disrupted upon subsequent heating and cooling. POLYM. ENG. SCI., 54:1383–1393, 2014. © 2013 Society of Plastics Engineers

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Section: Shear Rheology and Gpcmentioning

confidence: 75%

The influence of thermo-mechanical history on structure development of elastomeric and amorphous glass thermoplastic polyurethanes

Silva

Meltzer²,

Liu

et al. 2013

Polym Eng Sci

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“…Many researchers have studied the mechanisms and kinetics of the thermal decomposition of PU for the sake of improving its thermostability . Normally, decomposition of HSs is the first step in the process of the thermal decomposition of PU because the decomposition temperatures of urethane, allophanate, and urea bonds within HS are much lower than that of SSs.…”

Section: Resultsmentioning

confidence: 99%

Crystallinity evolution of soft segments during the synthesis of polyester‐based waterborne polyurethane

Cao

Xia

Liu

et al. 2013

J of Applied Polymer Sci

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Polyester‐based waterborne polyurethane (WPU) dispersions having poly(ethylene glycol) adipate diol, isophorone diisocyanate, and hexamethylene diisocyanate as the main raw materials were synthesized by an acetone process. In each step of the synthesis process, the intermediate products were collected, and the crystallization morphologies and relative crystallinity (X) of the soft segments (SSs) in their films were investigated by means of polarizing optical microscopy, differential scanning calorimetry, and X‐ray diffraction. The fracture surfaces and thermostability of the intermediate films were also investigated by scanning electron microscopy (SEM) and TGA, respectively. The results show that the crystalline dimensions of the SSs decreased substantially during the synthesis process of WPU. X of the SSs decreased after the prepolymerization reaction and increased after the hydrophilic chain‐extending reaction, then decreased after emulsification, and finally increased after the secondary chain‐extending reaction. Moreover, The SEM photos indicate that with decreasing crystalline dimensions, the fracture mechanisms of the intermediate films varied gradually from brittle failure to ductile fracture. The thermostability of the intermediates obtained in each step of the synthesis process was in accordance with the variation tendency of the X of the SSs. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40270.

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“…Note that Yang et al [106] studied the dependence of the depolymerization efficiency on the nature of isocyanate and alcohols groups. Endres et al [107] reported on a theoretical approach to the kinetics of the thermal decomposition of molten TPU under conditions of thermoplastic processing.…”

Section: Urethanesmentioning

confidence: 99%

Reactive Processing of Thermoplastic Polymers: A Review of the Fundamental Aspects

Cassagnau

Bounor‐Legaré

Fenouillot

2007

International Polymer Processing

100

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This work is dedicated to Dr. Alain Michel for his retirement and in memory of Prof. Morand Lambla. Dr. Michel and Prof. Lambla were the pioneers of the development of reactive processing in FranceThe review is devoted to the fundamental aspects of the reactive processing of thermoplastic polymers. First of all, some reactive processing examples, including polymer grafting (vinyl silane, maleic anhydride) and/or functionalization, bulk polymerization (urethane, lactams, acrylate, e-capolactone), polyester modification and new copolymers synthesis, are presented. From a fundamental point of view, the review covers the state of the art in the domains of rheology (specifically modelling of rheo-kinetics), diffusion and mixing in highly viscous reactive or non reactive media. Finally, 1, 2 and 3-D simulation of the reactive extrusion process in twin-screw extruder is reported at the end of the review.

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The Kinetics of the Thermal Decomposition of Thermoplastic Polyurethane Elastomers under Thermoplastic Processing Conditions

Cited by 20 publications

References 12 publications

The influence of thermo-mechanical history on structure development of elastomeric and amorphous glass thermoplastic polyurethanes

The influence of thermo-mechanical history on structure development of elastomeric and amorphous glass thermoplastic polyurethanes

Crystallinity evolution of soft segments during the synthesis of polyester‐based waterborne polyurethane

Reactive Processing of Thermoplastic Polymers: A Review of the Fundamental Aspects

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