Reliable method for determining the complete kinetic and thermodynamic information for thermal degradation of polymers in a multi-step process
- 69 Downloads
Proposed approach enables a reliable determination of kinetic and thermodynamic behaviors for thermal degradation of polymers. As a model polymer, poly(ethylene oxide) with average molecular weight Mv ~ 100.000 (PEO100) was used. Two-component continuous distribution kinetics best describes PEO100 thermal degradation, involving two main reactions with different values of reaction orders. Procedure enables the check of existence of true or real enthalpy–entropy compensation (EEC). It was established that in the case of random scission reaction step, the artificial EEC emerges. For second reaction step which involves β-scission reaction step (“slow” step), true (real) EEC emerges. It was found that this reaction step is responsible for occurrence of successive micro-phase transitions. These transitions are associated with significant reduction of PEO100 crystallinity through a hinder effect on polymer chains. It was concluded that these transitions are cyclic and reversible, related to the change of mechanical properties of the polymer.
KeywordsMulti-step thermal degradation Carnot cycle model Enthalpy–entropy compensation Micro-fragmentation (kernel) distribution Micro-phase transitions
The author would like to thank for the financial support of Ministry of Education, Science, and Technological Development of the Republic of Serbia under the Project 172015.
Compliance with ethical standards
Conflict of interest
The author declares that there is no conflict of interest.
- 9.ASTM E1582-17 Standard test method for temperature calibration of thermogravimetric analyzers. ASTM International, West Conshohocken, PA, p 2017Google Scholar
- 15.Akahira T, Sunose T (1971) Method of determining activation deterioration constant of electrical insulating materials. Res Rep Chiba Inst Technol (Sci Technol) 16:22–31Google Scholar
- 34.Lide DR (1995) Handbook of chemistry and physics76th edn. CRC Press, New YorkGoogle Scholar
- 37.Jarullah AT (2011) Kinetic modelling simulation and optimal operation of trickle bed reactor for hydrotreating of crude oil. Thesis for the Degree of Doctor of Philosophy (Ph.D), School of Engineering, Design and Technology University of Bradford, United Kingdom, UK, Bradford Library, pp. 1–260Google Scholar
- 41.Draper NR, Smith H (1998) Applied regression analysis3rd edn. Wiley, New York, pp xvii–x706Google Scholar