Characterization of Poly(Ethylene Terephthalate) by Torque Rheometry

Abstract

Polymer processing parameters may considerably affect final product characteristic as, if properly chosen, these parameters may lead to products with optimal properties. The aim of this work is to evaluate the rheological characteristics of poly(ethylene terephthalate) (PET) by torque rheometry, as well as to estimate its incipient degradation rate during processing in an internal laboratory mixer. In order to estimate the temperature coefficient of the viscosity (β), and the pseudoplasticity index (n) of PET, two sets of experiments need to be performed. In the first one, the polymer is processed at three different temperatures at a single rotor speed for 10 min, getting temperature coefficient of the viscosity equal to β = 0.053 °C-1. In the second set of experiments, the resin (PET) is processed at a single temperature at six different rotor speeds for the same time interval and the pseudoplasticity index was determined, n = 0.78. From the results obtained, it is possible to indicate the internal mixer as an equipment not only for mixing polymers or composites, but as a tool for determining important rheological variables for predicting degradative processes.

Transforming vulcanized styrene–butadiene waste into valuable raw material: an opportunity for high-impact polypropylene production

“…As reported [27][28][29], torque is proportional to the polymer viscosity, i.e., higher torque corresponds to higher viscosity. In Fig.…”

On the Production of Poly(Lactic Acid) (PLA) Compounds with Metallic Stearates Based on Zinc, Magnesium and Cobalt. Investigation of Torque Rheometry and Thermal Properties

“…Tests were carried out in the internal mixer at a constant rotors rate (Massachusetts, USA), whereas the torque (Z) is directly proportional to the viscosity (η) of the molten polymer during the last processing stage. 53,54 The torque also depends on the temperature and, therefore, its variation during the final processing stage can be attributed to the combined effect of the melt temperature change and the matrix weight molecular change. 55 The temperature effect on the viscosity and torque can be eliminated using the adjusted torque (Z*), 56 according to equation (1)Where: Z* is the adjusted torque to the reference temperature T*.…”

Tailoring polyamide 6 to exhibit super‐tough behavior and high thermomechanical stability: The role of AES and EPDM‐MA hybridization

“…According to the literature, 48,49 when the same processing conditions are used, torque is directly proportional to the viscosity of a polymer system. Figure 2a shows that PA6 has lower torque and, consequently, lower viscosity than the other neat polymers.…”