Data acquisition rheometer

Melt viscosities were measured using an Instron capillary melt rheometer (Model 3210) using a 0.050-in. diameter capillary (L D = 40 1). Corrected viscosities were calculated in the conventional manner. In all cases, samples were preheated for 7 min prior to data acquisition. 

Sample, stored in an appropriate clean container (sealed if solvent loss is an issue) Controlled-rate or controlled-stress rotational rheometer with Computer control and appropriate software for instrument control, data acquisition, and model fitting... 

Rotational rheometer (unithi.i e.g., Bohlin Instruments, Chandler Engineering) controlled stress (for applied step shear stress) or controlled strain (for applied step shear strain) with appropriate software for rheometer control, data acquisition, and data analysis... 

In order to facilitate rapid melt viscosity measurement and data analysis a modified Gflttfert capillary rheometer has been interfaced to a Hewlett-Packard data acquisition system. All test parameters (temperature, barrel pressure, etc) are monitored automatically and the data is stored on magnetic tape. After testing is complete, raw data is entered into an analysis program used to compute tables and draw plots of shear stress, shear rate, and apparent viscosity. Examples of the application of this system to commercial polymers are discussed. 

All variables in these equations are fixed except for piston velocity and melt pressure which are measured experimentally. An HP 3052A data acquisition system is used to acquire raw data from a Gflttfert capillary rheometer and to calculate and plot viscosity data. 

Significant savings in data acquisition and analysis time have resulted from the automation of our rheometer. Piston velocities are now determined rapidly and more accurately than previously had been possible. Preliminary data is quickly and easily plotted thus aiding the decisions on further experimentation. 

The reactions were monitored at ambient conditions, 23 C. Programs created in Rheoloader software were downloaded to two instruments, through a laboratory personal computer s (PC s) serial or RS-232 port. These rheometers were then disconnected from the PC and run in Standalone mode. The subsequent data output was sent to dot-matrix line-printers via parallel-port connections from each instrument. A third instrument was run in External mode using Rheocalc software for instrument control and data acquisition. The data were saved as a file on the PC, Three separate aliquots from each given batch were simultaneously tested, using the three instruments. 

LVDV-111+ rheometers were used with LV-4 spindles and SP-7Y Quick Connect Couplings. The reaction mixtures were contained in SC4-13RD disposable sample chambers. Brookfield Thermoses " heaters with Programmable Temperature Controllers were used and the epoxy cures studied at (1) 50°C and (2) 60 C. The control and data acquisition algorithm was run through a Rheocalc software program. 

The bending beam rheometer (Figure 4.21) is composed of a loading frame with test specimen supports, a controlled low/very low temperature liquid bath that maintains the test specimen at the test temperature and provides a buoyant force to counterbalance the force resulting from the mass of the test specimen and a computer-controlled data acquisition system for the execution of the test and the processing of the results. 

The first main feature of the System 4 RMS is its ability to characterize a wider range of the above systems than any other current rheometer. Several drives and stress transducers are required the wide range of modes, rates and materials to be handled would mean that no single drive/transducer combination would be sufficiently flexible and accurate. Instead, the System 4 RMS uses a turret with four different drive or transducer units one unit is used for steady shear tests, one for oscillatory shear, one for tension-compression and bending and one unit is used for low-viscosity-high-shear-rate tests on fluids. The second main feature of the new machine is its completely automatic microprocessor control coupled with data acquisition and reduction. Without doubt, this new rheometer will result in rheo-metrical tests being carried out more reliably, accurately and quickly than previously. 

The capillary rheometer is a valuable tool for predicting the processability of thermoplastic resins. This is done by measuring melt viscosities at shear rates and temperatures commonly encountered in extrusion and injection molding. This procedure is difficult and time consuming due to the complex nature of rheological measurements and analyses. An automated system for acquisition and analyses of capillary rheometer data has been developed to speed up and simplify this important analytical technique. 

The rheological measurements were made using a controlled-stress Rheometrics dynamic stress rheometer (SR 500) with a data module and computer acquisition system. The measuring head was a parallel-plate system with diameter 2.5 and 4 cm and a gap of 1 mm. The steady-state viscosity curves, the creep curves and the components of the complex modulus and the complex viscosity were determined in the temperature region between 170 and 230 °C in a dry nitrogen atmosphere. Samples were produced in the form of injection-moulded disks. Orchestrator 6.5.5 software was used to analyse the data. The characteristics of materials investigated are summarized in Table 1. 

For the DHR-3, an apparent maximum in the go-curve was observed at 23 rad/s. This maximum is believed to be caused by instrument inertia effects. When using the DHR-3 in the correlation acquisition mode, the transient data that is Fourier-transformed by the software is the raw torque data. For a CMT-rheometer the raw torque Mr is the sum of the sample torque Ms and an additional contribution caused by instrument inertia M/ as shown in Eq. 6 [11]. 

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