Model-free kinetics software

Model-free kinetics software employs numerical integration methods to measure activation energy versus conversion from cure exotherms at three or more heating rates, or from isothermal data at three or more temperatures. In both cases a minimum of four runs is recommended. Predictions like conversion-time plots and calculated DSC curves are made using Eq. (3.31). An advanced version of MFK software allows analysis of data from arbitrary heating programs, such as combined ramp and isothermal. A drawback of the commercial software is that a discrete mathematical relationship is not produced that can be exported and incorporated into cure models. 

Rates of reaction of both these types of curing experiments are very useful to polymer scientists. There are several different kinetics software packages available to characterize materials. There are scanning kinetics, isothermal kinetics and model-free kinetics calculations. Each has its own unique application or is best suited for certain applications. Figure 6 depicts the thermal curve of an epoxy cure with a second curve superimposed representing the percent area as the reaction advances. 

Vyazovkin (1997, 2001) developed an enhanced isoconversional method that allows evaluation of an effective activation energy ( ) as a function of the extent of reaction (a). This methodology, often referred to as model-free kinetics (MFK), is described in Section 3.5. The MFK software allows calculations such as conversion-time plots at selected temperatures that can be compared with actual measured data. It also allows the calculation of DSC curves that can be compared with actual measured DSC curves to help validate the analyses. The same curves analyzed by ASTM kinetics may be evaluated by MFK kinetics, and the same guidance is given. MFK kinetics is very comprehensive in that it is applicable to the simplest as well as to the most complex cure reactions, provided that a baseline can be drawn between a clear beginning and a clear end of the reaction. But it should be pointed out that the software is provided only by Mettler Toledo and Perkin-Elmer. For other users it is possible to measure versus conversion by the ASTM method and generate a spreadsheet with the appropriate MFK equation [e.g., Eq. (3.31) in Chapter 3], to calculate conversion-time plots. 

Kinetic analysis according to the model-free approach by Kissinger-Akahira-Sunose [25, 26] was performed with the computer program Excel. For kinetic analysis according to the advanced Vyazovkin method [27], the STAR software... 

A newly available simulation code for gas-phase kinetics is Kintecus (2014), which is a commercial code, but with a free licence available for academic research or education. Kintecus primarily communicates with the user through an Excel table, although Excel is not required to run Kintecus, since it can be nm from a command line. Kintecus is a chemical modelling software package for the simulation of combustion, nuclear, biological, enzyme, atmospheric and many other... 

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