Sentmanat extensional rheometer

Figure 10.22 Sketch showing the principle of operation of the Sentmanat extensional rheometer (SER), which is designed to be used as a fixture in a standard rotational melt rheometer. One of two cylinders is driven directly by the rheometer motor, while a gear train drives the slave drum.The thin, rectangular sample is clamped at its ends to the cylinders.The torque on the drive shaft is proportional to the tensile stress in the sample. Sketch courtesy of Jen Tiang.

FIGURE 7.23 Photographs of a Sentmanat extensional rheometer (SER) illustrating the mode of operation (center) and mounting configurations for two commercial rotational rheometers (left Rheometrics Scientific Ares right Anton Paar MCR). (Data from Sentmanat,... 

Three HIPS resins possessing distinct rheological properties were utilized in this study STYRON 1200, 1170, and 484. These resins have melt flow rates (MFR) of 5.0, 2.1, and 2.8 g/10 min (200T05kg) and will be referred to in the paper as HIPS 1, HIPS 2, and HIPS 3, respectively. The dynamic mechanical spectroscopy measurements (viscosity vs. frequency and temperature, loss and storage modulus vs. frequency and temperature) were performed on a TA Instruments ARES rheometer. The measurements were obtained at three different temperatures 170, 190, 210, and 2301C. The uniaxial extensional viscosity measurements were performed at three Hencky rates 0.1, and 10s on a SER (Sentmanat Extensional Rheometer, Xpansion Instruments) at 1701C. 

Extensional viscosity was measured at 170°C on a Sentmanat Extensional Rheometer (SER) fixture (Xpansion Instruments).[1] The SER is based on a dual drum system. It is designed as a fixture of a standard rotational rheometer which consists of a master and slave wind-up dmms coupled via intermeshing gears. A constant Hencky strain rate is obtained simply by setting a constant winding speed. The SER fits inside the environmental chamber of an Advanced Rheometric Expansion System (ARES) rheometer. Tests were carried out on strips cut out of a 0.5 mm thick compression molded sheet. Constant Hencky strain rates (1 and 10 s ) were applied and the time-dependent stress was determined from the measured torque and the sample time-dependent cross-section. The extensional viscosity, tie, was obtained by dividing the stress by the Hencky strain rate. 

Extensional viscosity from Sentmanat Extensional Rheometer (SER)... 

Sentmanat extensional rheometer (Figure 7) [34] has been employed for transient extensional rheology measurements of the linear (mLLDPE low) and branched (mLLDPE high) polymer samples at 140°C as visible in Figure 8. It is clearly visible that an increase in the level of the long chain branching lead to increase in the extensional strain hardening. 

Fig. 12.25 The Universal testing platform fitted on a rotational Rheometrics RDA II rheometer host station. The two counterrotating cylinders where the film is mounted cause the application of the extensional strain. [Reprinted by permission from E. G. Muliawan, S. G. Hatzikiriakos, and M. Sentmanat, Melt Fracture of Linear Polyethylene, Int. Polym. Process., 20, 60 (2005).]...

---