Comparison of entry flow techniques for measuring elongation flow properties

The elongation viscosity of linear low density polyethylene and low density polyethylene were estimated using converging flow and stagnation flow devi ces. Results were obtained from the converging flow rheometer using the ana lyses proposed by Binding [1] and Cogswell [2]. These results were compared with an estimate of uniaxial elongation viscosity obtained with the stagna tion flow rheometer similar to that proposed by Mackay et al. [3]. The resu lts show that the elongation viscosities determined by both flow geometries are comparable. Also, the measured elongation viscosity is affected to a s mall degree by geometric properties for converging flow. (C) 1999 Elsevier Science B.V. All rights reserved.