Rheological mechanical spectrometer

Rheological Properties Measurements. The viscoelastic behavior of the UHMWPE gel-like systems was studied using the Rheometric Mechanical Spectrometer (RMS 705). A cone and plate fixture (radius 1.25 cm cone angle 9.85 x 10" radian) was used for the dynamic frequency sweep, and the steady state shear rate sweep measurements. In order to minimize the error caused by gap thickness change during the temperature sweep, the parallel plates fixture (radius 1.25 cm gap 1.5 mm) was used for the dynamic temperature sweep measurements. 

The rheological experiments were performed on a Rheometrics Mechanical Spectrometer RMS 705F. Cone and plate geometry was used in order to generate a homogeneous shear history throughout the sample, a prerequisite in order to analyse transient behaviour. All experiments have been performed at 293K. 

Rheology. The rheological properties of the blends and their components were determined on a Rheometrics Mechanical Spectrometer (RMS 800). Three kinds of dynamic oscillatory measurements (i.e. temperature, time, and frequency sweeps) were carried out. All experiments were done by using a parallel plate attachment with a radius of 12.5 mm and a gap setting from 1.2 to 1.8 mm. There was no significant dependence of the experimental results on the gap setting. 

Two liquid crystalline copolyesters of 60 mole % PHB/PET and 80 mole % PHB/PET were used in this study. These samples were supplied by Tennessee Eastman and the properties are given elsewhere. Rheological properties were measured under various conditions of shear and thermal history using a 0.1 radian cone and plate attachment of a Rheometrics Mechanical Spectrometer (RMS). Various types of flow histories were used in this study and these are listed below ... 

Rubber particle-size distribution is usually measured with a Coulter coimter or directly from electron photomicrographs (110,343) the latter also gives details of particle morphology. Rheological studies are made with a modified tensile tester with capillary rheometer (ASTM D1238-79) or with the powerful Rheometrics mechanical spectrometer (344). For product specifications, a simple melt-fiow test is used (ASTM D1238 condition G) with a measurement of the heat-distortion... 

Using a Rheometrics mechanical spectrometer and powdered polymer samples, the authors compared the rheological behaviour of two polymers with similar chemical compositions but different structures. The rheological profiles of polymers 21 and 22 were determined between 140 and 400°C by increasing the temperature at 10°C min from 140 to 190°C and from 300 to 400°C. In the predominant region of isoimide-imide conversion (190-300°C), the temperatme was raised by 2 or 5°C increments, the dynamic viscosity rj being measured at each temperature step. At 190°C, the viscosity of poly(isoimide) 21 was approximately 5 X 10 Pas and decreased to a minimum value of 10 Pas at 243°C as the polymer softened and melted. Thermal conversion to polyimide 22 concurrently... 

Siloxanes A2 and A were obtained from Petrarch Chemicals and B2, M 1400, was obtained from Prof. J. P. Kennedy, Univ. of Akron, Akron, OH. The catalyst was used as a 0.1% stock solution in toluene. Rheological measurements during end-linking were made with a Rheometrics System IV Mechanical Spectrometer. N IR data were obtained with the Nicolet 293A 300 MHz spectrometer. FTIR spectra were obtained on a Nicolet 60SX using 64 scans. 

The experimental studies of the influence of fillers on the rheological properties of polymer melts by White et al. [29] best illustrate the effect of filler type. The steady shear elastic data were generated in terms of the first normal stress difference using the cone and plate arrangement of the Rheometrics Mechanical Spectrometer at a fixed temperature of 180°C. 

The rheological data needed for constructing a rheogram are obtained on sophisticated scientific instruments, namely, rheos mneters, oqnllary rheometers, mechanical spectrometers, and so forth. These instruments are very expensive and require trained operators. Thus, the collection of the necessary flow data is not always possible due to constraints of finance and the limited tedinical capabilities of most polymer processors. 

The rheological behavior and melt viscoelastic properties of the samples were studied using a rheometric mechanical spectrometer (Paar Physica USD200) with a parallel plate (diameter =2.5 cm gap =1 mm). All measurements were performed at a temperature of 200 °C, frequency range of 0.01-1000 sec, and strain amplitude of 1%. 

Rheological Properties. Rheological studies of the nanocomposites were performed using a Rheometrics Mechanical Spectrometer model 800 on 25mm diameter samples punched from the injection molded plaques. Dynamic oscillatory shear flow measurements of the nanocomposites were made in the linear regime of strain in a frequency range of 0.1 to 100 rad/s under a continuous nitrogen atmosphere. 

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