Rheology of thermoplastic polyurethanes

TPUs are often referred to as multiblock copolymers. In order to have a better understanding of the rheological behavior of TPUs, one must first understand the relationships between the chemical structure and the morphology thus, a complete 

Long-chain diol Diisocyanate Chain extender Urethane linkage 

Copyright 1971, with permission from John Wiley Sons.) 

Effect of Thermal History on the Rheological Behavior of TPUs 

In this section, we first present the effects of thermal history on the dynamic moduli of TPU during isothermal annealing and then interpret the observations using information on the formation of hydrogen bonds during isothermal annealing. 

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EFFECT OF THERMAL HISTORY ON THE RHEOLOGICAL BEHAVIOR OF THERMOPLASTIC POLYURETHANES... 

In the present study we utilized Plasticorder torque values (polymer viscosity) on a relative basis, principally to follow the course of thermoplastic polyurethane elastomer polymerization, and the effect of several relevant variables on this polymerization. These torque data, expressed in meter-grams, served our purposes well, and we have not attempted to translate them to absolute rheological units. Such translation, which is a rather complex problem, has been addressed by others using a different rotor type and other polymers in the Plasticorder.14 That study concluded that the shear rate, y, of the Brabender Plasticorder with a somewhat different rotor configuration (roller blade) is in the range of 23 - 228 sec 1 over the rotor speed range of 30 - 200 rpm. 

Wang X, Luo X, Wang X. Study on blends of thermoplastic polyurethane and aliphatic polyester morphology, rheology, and properties as moisture vapor permeable films. Polym Test 2005 24(1) 18-24. 

Beloqui BJ, Garcia JCF, Martinez JMM, et al. Rheological properties of thermoplastic polyurethane adhesive solutions containing fumed silicas of different surface areas. Int J Adhes Adhes August 1999 19 321-8. 

Elfect of thermal history on the rheological behavior of thermoplastic polyurethanes. Macromoiecules, 33,... 

Sanchez-Adsuar M S, Papon E and Villeiiave J J (2000) Rheological characterization of thermoplastic polyurethane elastomers, Polym Inter 49 591-598. 

Yoon PJ (2000). Effect of Thermal History on the Rheological Properties of Thermoplastic Polyurethanes, Doctoral Dissertation at the University of Akron, Akron, Ohio. 

Wang, X., X. Luo, and X. Wang, Study on Blends of Thermoplastic Polyurethane and Aliphatic Polyester Morphology, Rheology, and Properties as Moisture Vapor Permeable Films, Polymer Testing, 24(1), 18-24, 2005. 

Short fiber reinforcement of TPEs has recently opened up a new era in the field of polymer technology. Vajrasthira et al. [22] studied the fiber-matrix interactions in short aramid fiber-reinforced thermoplastic polyurethane (TPU) composites. Campbell and Goettler [23] reported the reinforcement of TPE matrix by Santoweb fibers, whereas Akhtar et al. [24] reported the reinforcement of a TPE matrix by short silk fiber. The reinforcement of thermoplastic co-polyester and TPU by short aramid fiber was reported by Watson and Prances [25]. Roy and coworkers [26-28] studied the rheological, hysteresis, mechanical, and dynamic mechanical behavior of short carbon fiber-filled styrene-isoprene-styrene (SIS) block copolymers and TPEs derived from NR and high-density polyethylene (HOPE) blends. 

Vlad S, Oprea S. Evaluation of rheological behaviour of some thermoplastic polyurethane solutions. Eur Polym J 2001 37(12) 2461. ... 

Mi, H.-Y., Jing, X., Jacques, B.R., Tumg, L.-S., Peng, X.-F., 2013. Characterization and properties of electrospun thermoplastic polyurethane blend fibers effect of solntion rheological properties on fiber formation. Journal of Materials Research 28, 2339-2350. http //dx.doi. 

Evolution of Nonlinear Rheology and Network Formation during Thermoplastic Polyurethane Polymerization and Its Relationship to Reaction Kinetics, Phase Separation, and Mixing... 

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