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4666408 
Journal Article 
High strain extensional rheometry of polymer melts: Revisiting and improving the Meissner design 
Andrade, RJ; Harris, P; Maia, JM 
2014 
Yes 
Journal of Rheology
ISSN: 0148-6055 
58 
4 
869-890 
WOS:000339141600003 
A new extensional rheometer limited in achievable strain only by sample rupture is presented. The rheometer is based on the Meissner design of two pairs of counter-rotating rollers pulling a sample of fixed length but is small enough to fit inside the oven of a standard rotational rheometer and thus is dubbed the Meissner Extensional Rheometry Accessory (MERA). The true strain rate is calculated by visually accessing the sample during deformation using a high-speed digital camera. Extensional experiments were performed on three materials representing a wide range expected rheological behavior, a styrene-butadiene rubber blend, a linear polystyrene, and a branched low-density polyethylene. The MERA was able to accurately replicate the results of the well-known Sentmanat extensional rheometer (SER) design in terms of onset of strain-hardening and absolute transient extensional viscosity values. However, due to its design, it was possible to achieve homogeneous extensional flow up to real Hencky strains in excess of 8, which corresponds to a linear stretch in excess of 3000. By comparison, the SER is limited to one drum revolution, which corresponds to a Hencky strain of 3.5-4.0 or a maximum linear stretch of approximately 50. Previously the highest Hencky deformations reported in the literature are for the filament stretching extensional rheometer and Rheometric Scientific RME apparatus and in both cases approach 7, which corresponds to a linear stretch of approximately 1000. (C) 2014 The Society of Rheology.