Intensity of UV Light as Additional Parameter in Kinetic Analysis

Photoinduced curing reaction depends not on temperature only, but on the intensity of UV light.

Now in Kinetics Neo it is possible to create the common kinetic model depending on two parameters: temperature and intensity of UV light.

Partial Pressure of Gaseous Reactant as Additional Parameter in Kinetic Analysis

Many solid materials react with the gaseous component, for example during oxidation. The reaction rate in this case depends not only on the temperature but also on the concentration of the reactive gaseous component, which I proportional to the partial pressure of this component in the gaseous surrounding.

Now in Kinetics Neo it is possible to create the common kinetic model, depending on both external parameters: temperature and partial pressure of the gaseous reactant.

Total Pressure as Additional Parameter in Kinetic Analysis for Reactions in Inert Gas

Decomposition reactions with gaseous products can be pressure-dependent also in inert atmosphere. This happens for the reversible reactions where the presence of gaseous products in the reaction zone slows down the decomposition. Thus, for reversible reactions under the enhanced pressure of inert gas the decomposition happens at higher temperature.

Projects for Arbitrary Data Types, which Are Non-Standard in Kinetics Neo

Sometimes the type of measured data differ from the standard data types existing in Kinetics Neo and we got a lot of questions about kinetic analysis of this data https://kinetics.netzsch.com/en/f-a-q/is-it-possible-to-analyze-the-absorbance-or-concentration

For this reason, we have added two additional project types for arbitrary data.

The first one is the Arbitrary Differential Project for differential data, containing the reaction peak like DSC. It could be for example, the data from mass-spectrometry or differential thermal analysis.

The second project type is the Arbitrary Integral Project for integral data like TG. It could be the measured concentrations, conversion, storage modulus, absorbance or other similar data.

Curing Reactions with Diffusion Control for DEA or Rheology

Reactions of curing and cross-linking near glass transition temperature are diffusion controlled.

Sometimes it is impossible to measure them by DSC method, because after vitrification the curing reaction is very slow, and DSC signal is very weak. Therefore, other measurements methods are used for study this process, like Dielectric Analysis (DEA) or Rheometry.

Now the reaction with diffusion control, measured by DEA or Rheometry, can be also analyzed in Kinetics Neo:

Reversible Reactions

In reversible reactions A⇌B, two chemical reactions occur simultaneously.

In thermal analysis like DSC or TG, the system is open, and no equilibrium happens. The total reaction rate of measured data is the difference between the forward reaction and backward reaction:

Rection rate _total=Reaction rate _forward – Reaction rate _backward

Decomposition of Calcium carbonate under presence of carbon dioxide in reversible reaction and decomposition depends on the partial pressure of CO₂.

New reaction type DFn for diffusion with reaction of n-th order

Reactions in solids often depend on the particles geometry and therefore look like phase boundary reactions, which is partial case of n-th order reaction.

Many theoretical kinetic models do not consider such fact, and therefore can describe well only the initial part of experimental curve. In order to bring such models close to reality, in the literature the advance models are created, where initial part correspond to the pure theoretical model, and final part contains n-th order dependence.

Now we developed the new reaction typeDFn for the first-dimensional diffusion with n-th order. DFn reaction type considers diffusion process in the material during decomposition. It adds the diffusion mechanism to the classical reaction of n-th order (Fn).

Next figures present the rate of two-step decomposition for polymer with the fit according:

•  classical reaction Fn (bad fit) 
• fit for new reaction type DFn .

Kinetics for Incomplete Measured Data, Where Final Part of Reaction Is not Present

For some reactions the final part of reaction cannot be measured, and the final point of the measurement does not correspond to the conversion value 100%. For example, for curing reaction with diffusion control reaction goes very slow after vitrification and almost cannot be registered by DSC.

However, in some cases, the total effect (total peak area or total mass loss) can be sometimes estimated by other measurements or methods and this value can be used for calculation of conversion value.

Now we are able to calculate the conversion for incomplete data, where final part of reaction is not measured: