Conclusions on the MDR in Scanning Mode

The MDR can be driven in scanning mode in the same way as a calorimeter, with only one experiment with the same sample, whereas at least three experiments are necessary when using the MDR under isothermal condition. The main parameter of interest for this new way of using the MDR is the heating rate. As a conclusion, a value ranging from 2 to 10°C/min—or much better, from 2 to 5°C/min—should be selected. Of course, a lower value of the heating rate is responsible for a longer time of experiment. 

The profiles of temperature and state of cure are interesting pieces of information. In scanning mode for the MDR, a slight gradient of temperature is developed at the beginning of the experiment, but after a short time it becomes constant. 

The method of scanning mode for the MDR has been applied successfully to the other rubber compounds shown in Table 3.2 and 3.3. The kinetic parameters of the cure were obtained by nsing Eqnation 3.21, and the method of least squares was proved to be the best [23]. 

The effect of the heating rate as well as the quality of the rubber-die contact was also seriously considered [24] by using a rubber compound made of 100 parts EPDM with 2 parts sulfur and 50 parts C black. The kinetics of cure was expressed by Equation 3.19 and the parameters obtained nsing Eqnation 3.21. 

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. 

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