Influence of water content, time, and temperature on the rheological behavior of polyethylene terephtalate

• Published in: Journal of applied polymer science Vol. 116; no. 6; pp. 3525 - 3533
• Main Authors: Souza, A.M.C, Leprêtre, D.S, Demarquette, N.R, Lacrampe, M.F, Krawczak, P
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 15-06-2010; Wiley
• Subjects: Amplitudes; Applied sciences; Chemical Sciences; Exact sciences and technology; Moisture content; molecular weight distribution/molar; Organic polymers; Physicochemistry of polymers; Polyethylene terephthalates; Polyethylenes; Polymers; Properties and characterization; Rheological properties; rheology; Rheology and viscoelasticity; Rheometers; Shear tests; Time delay; viscoelastic properties; viscosity; Ethylene terephthalate polymer; Viscoelasticity; molecular weight distribution/molar; rheology; Molten state; Ester polymer; Temperature effect; Experimental study; Molecular weight property relation; viscoelastic properties; Shear viscosity; viscosity; Water content; Rheological properties
• ISSN: 0021-8995; 1097-4628; 1097-4628
• DOI: 10.1002/app.31885

In this work, the main factors affecting the rheological behavior of polyethylene terephtalate (PET) in the linear viscoelastic regime (water content, time delay before test, duration of experiment, and temperature) were accessed. Small amplitude oscillatory shear tests were performed after different time delays ranging from 300 to 5000 s for samples with water contents ranging from 0.02 to 0.45 wt %. Time sweep tests were carried out for different durations to explain the changes undergone by PET before and during small amplitude oscillatory shear measurements. Immediately after the time sweep tests, the PET samples were removed from the rheometer, analyzed by differential scanning calorimetry and their molar mass was obtained by viscometry analysis. It was shown that for all the samples, the delay before test and residence time within the rheometer (i.e. duration of experiment) result in structural changes of the PET samples, such as increase or decrease of molar mass, broadening of molar mass distribution, and branching phenomena.