The New Jersey Institute of Technology's
Electronic Theses & Dissertations Project

Title:	Rheological characterization of unmodified and chemically modified poly (ethylene terephthalate) resins
Author:	Quintans, Jorge
View Online:	njit-etd1998-091 (xii, 71 pages ~ 2.5 MB pdf)
Department:	Department of Chemical Engineering, Chemistry and Environmental Science
Degree:	Master of Science
Program:	Chemical Engineering
Document Type:	Thesis
Advisory Committee:	Xanthos, Marino (Committee chair) Yilmazer, Ulku (Committee member) Armenante, Piero M. (Committee member)
Date:	1998-05
Keywords:	Polymers--Rhelogy. Plastics--Testing. Polymer melting. Viscous flow.
Availability:	Unrestricted
Abstract:	Intrinsic viscosity (IV) has often been misused for estimating both melt viscosity and elasticity of poly(ethylene terephthalate) (PET). A rheological study was conducted to determine the variations between a virgin unmodified PET and a recycled and chemically modified PET, both having a reported nominal IV of 0.95. The modified material had a larger melt viscosity (capillary and dynamic) than the virgin material (by an average of 61%). The extrudate swell, a better indicator of melt elasticity, of the modified was more than 110% greater than that of the unmodified material. Activation energies for melt viscosity and extrudate swell were found to be approximately 20 KJ/mol and 3 kJ/mol respectively, for the unmodified material at high shear rates. The melt viscosity for both materials was found to be best fitted by the Cross Model using a least-squares fit.