Kinetic analysis of solid-state processes

2001 ◽  
Vol 16 (6) ◽  
pp. 1862-1871 ◽  
Author(s):  
Jiří Málek ◽  
Takefumi Mitsuhashi ◽  
José Manuel Criado
Keyword(s):  
Solid State ◽  
Kinetic Analysis ◽  
Crystallization Process ◽  
Good Description ◽  
Simple Method ◽  
Solid State Kinetics ◽  
Kinetics Of ◽  
Nonisothermal Conditions ◽  
Two Parameter

A simple method for kinetic analysis of solid-state processes has been developed. A criteria capable of classifying different processes is explored here with a view toward visualizing the complexity of solid-state kinetics. They provide a useful tool for the determination of the most suitable kinetic model. The method has been applied to the analysis of crystallization processes in amorphous ZrO2 and RuO2. It is found that the crystallization kinetics of as-prepared sample exhibits a complex behavior under nonisothermal conditions. This is probably due to an overlapping of the nucleation- and crystal-growth processes at the beginning of crystallization. As a consequence, the Johnson–Mehl–Avrami nucleation-growth model cannot be applied. A two-parameter autocatalytic model provides a good description of the crystallization process under isothermal and nonisothermal conditions.

scholarly journals Modeling the crystallization kinetics of polymers displaying high levels of secondary crystallization

2021 ◽  
Author(s):  
Catherine A. Kelly ◽  
Mike J. Jenkins
Keyword(s):  
Experimental Data ◽  
Visual Inspection ◽  
Crystallization Process ◽  
Primary Crystallization ◽  
Parallel Model ◽  
Secondary Crystallization ◽  
Multivariable Regression ◽  
Kinetics Of ◽  
Best Fit

AbstractThe isothermal crystallization of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) was evaluated using a range of models, namely, Avrami, simplified Hillier, Tobin, Malkin, Urbanovici–Segal, Velisaris–Seferis, and Hay. Two methods of model evaluation were used: determination of the parameters through traditional double log plots and curve fitting via nonlinear, multivariable regression. Visual inspection of the cumulative crystallization curves, calculation of the R2 value and standard error of the regression, and evaluation of the returned parameters were used to assess which model best describes the experimental data. The Hay model was found to generate the best fit, closely followed by the Velisaris–Seferis parallel model, suggesting that primary and secondary crystallization occur concurrently. The Avrami, Malkin, and Tobin models were found to perform well when the data is restricted to the region where primary crystallization dominates; however, they could not be used to successfully model the entire crystallization process. This work highlights the importance of selecting the most appropriate model for analyzing kinetics, especially when high levels of lamellar thickening and infilling occur during crystallization.

scholarly journals Determination of Michaelis parameters from differentials of progress curves

1983 ◽  
Vol 215 (3) ◽  
pp. 589-595 ◽  
Author(s):  
L C Petersen
Keyword(s):  
Steady State ◽  
Cytochrome C ◽  
Kinetic Analysis ◽  
Cytochrome C Oxidase ◽  
Enzyme Assay ◽  
Serine Proteinases ◽  
Steady State Concentration ◽  
Kinetics Of ◽  
State Concentration

First differentials of progress curves are easily obtainable in many enzyme assay systems. Such curves may be more readily applicable to kinetic analysis than are the usual progress curves. The theory for this approach is developed, and simple graphical procedures for the determination of Michaelis parameters are indicated. By using an electronic differentiator device the application of the method is demonstrated on the kinetics of three different serine proteinases with various synthetic substrates. Whenever the steady-state concentration of an intermediate of the reaction is proportional to the rate, the transition of this intermediate in substrate-depletion experiments may be analysed in similar terms. This is demonstrated with cytochrome c oxidase kinetics. A number of other possible applications are discussed.

Overall Kinetics of Natural Rubber Vulcanization at High Temperatures I—review of Investigation Techniques, Methods and Previous Results of Kinetic Analysis

1971 ◽  
Vol 44 (5) ◽  
pp. 1316-1325 ◽  
Author(s):  
R. B. Redding ◽  
D. A. Smith
Keyword(s):  
Natural Rubber ◽  
Kinetic Analysis ◽  
Kinetic Parameters ◽  
High Temperatures ◽  
Kinetic Data ◽  
Network Chain ◽  
Correct Determination ◽  
Kinetics Of ◽  
Overall Kinetics

Abstract Analysis of previously published cure data illustrates the importance of correct determination of the ultimate level of network chain density in the absence of reversion, and the correction of each kinetic data point for “reversion contributions”. A graphical procedure is described for the determination of kinetic parameters which takes these precautions into account.

scholarly journals Polymerization of Solid-State Aminophenol to Polyaniline Derivative Using a Dielectric Barrier Discharge Plasma

Plasma ◽  
2020 ◽  
Vol 3 (4) ◽  
pp. 187-195
Author(s):  
Ketao Chen ◽  
Meijuan Cao ◽  
Eileen Feng ◽  
Karl Sohlberg ◽  
Hai-Feng Ji
Keyword(s):  
Solid State ◽  
Dielectric Barrier Discharge ◽  
Barrier Discharge ◽  
Dbd Plasma ◽  
Simple Method ◽  
Dielectric Barrier ◽  
Vis Spectroscopy ◽  
Barrier Discharge Plasma ◽  
Kinetics Of ◽  
Keto Derivative

We present a method to prepare polyaminophenol from solid-state aminophenol monomers using atmospheric dielectric barrier discharge (DBD) plasma. The polymerizations of o-aminophenol and m-aminophenol are studied. The polymers were analyzed via Fourier-Transform inferred spectroscopy (FTIR) and ultraviolet-visible (UV-vis) spectroscopy. The kinetics of the polymerization reactions were investigated by using UV-vis and the polymerization was found to be first-order for both o-aminophenol and m-aminophenol. The resulting polymer film exhibits a conductivity of 1.0 × 10−5 S/m for poly-o-aminophenol (PoAP) and 2.3 × 10−5 S/m for poly-m-aminophenol (PmAP), which are two orders more conductive than undoped (~10−7 S/m) polyaniline (PANI), The PoAP has a quinoid structure and the PmAP has an open ring keto-derivative structure. The process provides a simple method of preparing conductive polyaminophenol films.

Sign in / Sign up

Export Citation Format

Share Document