Rubber process analyzer

J. S. Dick, and H. A. Pawlowski, Applications for the Rubber Process Analyzer. Rubber Division of the American Chemical Society, Nashville, Tennessee, November 3-6 (1992). 

Mooney Viscometer studies at 100°C and 120°C show lower viscosity of the Al-hlled gums. Lower viscosity compounds require less energy input for extrusion. Comparative results on the dynamic mechanical properties, measured using a rubber process analyzer (RPA), show that at the... 

FIGURE 17.6 Plot of tan S versus temperature for Al- and A2-cured compounds measured using a rubber process analyzer (RPA). 

The curing properties were determined with the aid of a rubber process analyzer (RPA 2000, Alpha Technologies) at a temperature of 160°C. The compounds were cured in a laboratory press at 160°C and 100 bar at a time corresponding to the fgo of the specific compound. 

Ethylene-Propylene-Diene Monomer (EPDM) Compounding Rubber Process Analyzer-Fourier Transform (RPA-FT) Results at 100°C Total Torque Harmonic Content (TTHC) versus Strain Fit Parameters of Equation 30.4... 

Dynamic-mechanical testing of cross-linked samples are often carried out with high precision on specimen strips in torsion mode, e.g., with a Rheo-metrics Dynamic Analyzer II (RDA) with a sample size of 28x10x2 mm. Here, temperature-and strain sweeps are performed in a displacement range from 0.01% to about 5% strain and a frequency range between 0.1 and 100 Hz. Dynamic mechanical testing of uncross-linked samples can be made, e.g., with a Rubber Process Analyzer RPA 2000 (Alpha Technologies) from 0.28% to 350% strain at various frequencies and elevated temperatures. 

Various techniques have been developed in turn the Mooney viscometer, the Wallace-Shawbury curometer, the oscillating disc rheometer (ODR), and the moving disc rheometer (MDR), in addition to the calorimetry techniques. The isothermal calorimetry and its counterpart in scanning mode, the isothermal moving disc rheometer (MDR), and the improvement of this last technique with the rubber process analyzer run in scanning mode, are considered. 

Finally, the history has been similar both with the MDR or the calorimeter. After being utilized under isothermal conditions a few decades ago, the calorimetry technique is now widely used in the scanning mode, and the MDR, quite recently, could be used in scanning mode with the rubber process analyzer. 

Based on theoretical studies, it has been proved that the MDR could be driven in scanning mode with a constant heating rate, leading to intaesting benefits. This faa was foimd to be true since the rubber process analyzer (RPA) is now launched on the market. Moreover, other more sophisticated modes of heating sean to be still of greater interest than the constant heating rate. 

Finally, it should be repeated that the best apparatus available, in our opinion, for determining simultaneously the conditions of temperature and time at which the rubber can be stored without an increase in stiffness is the rubber process analyzer (RPA) from Alpha Technologies, as it can be run with a programmed temperatnre. 

The rubber process analyzer (RPA 2000), recently available on the market, can be run either under isothermal temperature or with a programmed temperature, the time and temperature of the scorch of the cure of reaction are easily and precisely obtained. 

As already said, there was some difficulty in evaluating the conditions of the scorch time (i.e., the onset of vnlcanization at a given temperature with the isothermal ODR and the isothermal MDR) as the scorch time obtained was not associated with a known temperature. This has been an argument for developing the rubber process analyzer (RPA, Alpha Technologies), which can be run not only under isothermal conditions but also with aprogrannned temperature, giving then simultaneously the temperature and time for the scorch. 

The moving die rheometer, MDR, still widely used, is only run under isothermal conditions. Thns, three experiments are necessary to determine the three parameters that are able to describe the effect of temperature on the rate of cure. A better use of the MDR technique is surely obtained by programming the temperature, in the same way as calorimetry was run. Hence, the rubber process analyzer (RPA), which can be run either nnder isothermal conditions or with a programmed temperature, has been recently launched on the market. Nevertheless, as shown in Chapter 3, by using various ways of heating, the usual linear temperature programming is perhaps not the best. 

Dick. John S. and Pawlowski. Henry. Applications for the rubber process analyzer. Rubber dt Plastics. Wh.v (April 26, May 10. 1993). 

Figure 21.1 shows the log plots of rubber process analyzer (RPA) complex dynamic viscosity (r) ) vs shear rate (from changes in frequency, in radians/ second). The results characterize the rubber as a pseudoplastic material in... 

Chen YK, Xu CH (2011) Specific nonlinear viscoelasticity behaviors of natural rubber and zinc dimethacrylate composites due to multi-crosslinking bond interaction by using rubber process analyzer 2000. Polym Compos 32 1593-1600... 

The ASTM D1646 Mooney viscosity test and ASTM D6204 Part A Rubber Process Analyzer are commonly used to classify IR. There is no official classification system. However, Mooney viscosity and percent 1,4-ds-polyisoprene purity are two important parameters for classification purposes. 

Sample preparation. All ingredients were mixed in an open two-roll laboratory mill at room temperature. The rotors operated at a speed ratio of 1 1.4. Rubber compounds were vulcanized in an electrically heated hydraulic press. The compounds were cured into 0.25 mm thick films at 150 °C for 15 min according to the optimum cure time ( 90) derived from the curing curves previously determined by means of a Rubber Process Analyzer (RPA2000 Alpha Technologies). Rectangularshaped specimens were mechanically cut out from the film samples. 

Strain sweep tests (rubber process analyzer, updated for fourier transform rheometry) on molten virgin and carbon black filled poly(ethylene-co-butyl acrylate) composites and likely morphology in both the solid and molten states. 

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