Simplified approach to modelling the catalytic degradation of low-density polyethylene (LDPE) by applying catalyst-free LDPE-TG profiles and the Friedman method

  • Gorazd BerčičEmail author
  • Petar Djinović
  • Albin Pintar


The course of the thermogravimetric degradation of LDPE in the presence of different aluminosilicate catalysts was modelled by applying a differential isoconversional Friedman approach. An analysis of catalyst-free PE-TG profiles confirmed that the degradation profiles predicted by various reaction models overlap over the entire conversion range once the data are analysed using a differential isoconversional Friedman approach. The results demonstrate that the catalytic degradation of LDPE can be predicted by a correlation twin, i.e. the two specific functional relations between the activation energy, pre-exponential factor and conversion. The crucial step for ensuring good agreement between the predicted and the measured profiles is to extrapolate the discrete values of the activation energies and pre-exponential factors to the zero conversion. It turns out that linear extrapolation and interpolation from the discrete values outperforms regression functions based on various order polynomials, and that apparent deviations from the global trend at lower conversions are not a consequence of the misinterpretation of the experimental results but are an experimental fact. The assumption about the compensation effect between the pre-exponential factor and activation energy holds within the conversion range from 10 to 90%. However, it is generally unsuitable for modelling purposes due to the uncertain extrapolation of the kinetic parameters to the zero conversion.


Catalytic degradation Catalyst-free TG profiles Isoconversional analysis Polyethylene Friedman 



PD and AP acknowledge financial support through research program P2-150 and research Grant Z2-5463 provided by Slovenian Research Agency. GB acknowledges Slovenian Research Agency for funding through research program P2-152.

Supplementary material

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  1. 1.
    Saha B, Ghoshal AK. Model-free kinetics analysis of ZSM-5 catalyzed pyrolysis of waste LDPE. Thermochim Acta. 2007;453:120–7.CrossRefGoogle Scholar
  2. 2.
    Araujo AS, Fernandes VJ Jr, Fernandes GJT. Thermogravimetric kinetics of polyethelyne degradation over silicoaluminophosphate. Thermochim Acta. 2002;392–393:55–61.CrossRefGoogle Scholar
  3. 3.
    Coelho A, Costa L, Marques MM, Fonseca IM. Lemos MANDA, Lemos F. The effect of ZSM-5 zeolite acidity on the catalytic degradation of high-density polyethylene using simultaneous DSC/TG analysis. Appl Catal A. 2012;413–414:183–91.CrossRefGoogle Scholar
  4. 4.
    Marcilla A, Beltrán MI, Gómez-Siurana A, Navarro R, Valdés F. A global kinetic model as a tool to reproduce the deactivation behaviour of the HZSM-5 zeolite in the catalytic cracking of low-density polyethylene. Appl Catal A. 2007;328:124–31.CrossRefGoogle Scholar
  5. 5.
    Marcilla A, Gómez-Siurana A, Valdés F. Catalytic cracking of low-density polyethylene over H-Beta and HZSM-5 zeolites: influence of the external surface. Kinetic Model Polym Degrad Stab. 2007;92:197–204.CrossRefGoogle Scholar
  6. 6.
    Marcilla A, Gómez-Siurana A, Valdés F. Catalytic pyrolysis of LDPE over H-beta and HZSM-5 zeolites in dynamic conditions Study of the evolution of the process. J Anal Appl Pyrolysis. 2007;79:433–42.CrossRefGoogle Scholar
  7. 7.
    Sarathy S, Wallis MD, Bhatia SK. Effect of catalyst loading on kinetics of catalytic degradation of high density polyethylene: experiment and modelling. Chem Eng Sci. 2010;65:796–806.CrossRefGoogle Scholar
  8. 8.
    Garforth AA, Lin YH, Sharratt PN, Dwyer J. Production of hydrocarbons by catalytic degradation of high density polyethylene in a laboratory fluidised-bed reactor. Appl Catal A. 1998;169:331–42.CrossRefGoogle Scholar
  9. 9.
    Renzini MS, Lerici LC, Sedran U, Pierella LB. Stability of ZSM-11 and BETA zeolites during the catalytic cracking of low-density polyethylene. J Anal Appl Pyrol. 2011;92:450–5.CrossRefGoogle Scholar
  10. 10.
    Sakata Y, Uddin MA, Muto A, Kanada Y, Koizumi K, Murata K. Catalytic degradation of polyethylene into fuel oil over mesoporous silica (KFS-16) catalyst. J Anal Appl Pyrolysis. 1997;43:15–25.CrossRefGoogle Scholar
  11. 11.
    Council Decision of 19 December 2002 establishing criteria and procedures for the acceptance of waste at landfills pursuant to Article 16 of and Annex II to Directive 1999/31/EC. Off J Eur Commun. 2003.
  12. 12.
    Covarrubiasa C, Graciab F, Palzab H. Catalytic degradation of polyethylene using nanosized ZSM-2 zeolite. Appl Catal A. 2010;384:186–91.CrossRefGoogle Scholar
  13. 13.
    Ibañez M, Artetxe M, Lopez G, Elordi G, Bilbao J, Olazar M, Castaño P. Identification of the coke deposited on an HZSM-5 zeolite catalyst during the sequenced pyrolysis–cracking of HDPE. Appl Catal B. 2014;148–149:436–45.CrossRefGoogle Scholar
  14. 14.
    Djinović P, Tomše T, Grdadolnik J, Božič Š, Erjavec B, Zabilskiy M, Pintar A. Natural aluminosilicates for catalytic depolymerization of polyethylene to produce liquid fuel-grade hydrocarbons and low olefins. Catal Today. 2015;258:648–59.CrossRefGoogle Scholar
  15. 15.
    Caldeira VPS, Santos AGD, Oliveira DS, Lima RB, Souza LD, Pergher SBC. Polyethylene catalytic cracking by thermogravimetric analysis. J Therm Anal Calorim. 2017. Scholar
  16. 16.
    Saha B, Reddy PK, Chowlu ACK, Ghoshal AK. Model-free kinetics analysis of nanocrystalline HZSM-5 catalyzed pyrolysis of polypropylene (PP). Thermochim Acta. 2008;468:94–100.CrossRefGoogle Scholar
  17. 17.
    Silva EFB, Ribeiro MP, Galvão LPFC, Fernandes VJ, Araujo AS. Kinetic study of low density polyethylene degradation on the silicoaluminophospate SAPO-11. J Therm Anal Calorim. 2011;103:465–9.CrossRefGoogle Scholar
  18. 18.
    Berčič G, Djinović P, Pintar A. Procedure for generation of catalyst-free PE-TG profiles and its consequence on calculated activation energies. J Therm Anal Calorim. 2017;128:443–56.CrossRefGoogle Scholar
  19. 19.
    Shabtai J, Xiao X, Zmierczak W. Depolymerization-liquefaction of plastics and rubbers. 1. polyethylene, polypropylene, and polybutadiene. Energy Fuels. 1997;11:76–87.CrossRefGoogle Scholar
  20. 20.
    Ding W, Liang J, Anderson LL. Thermal and catalytic degradation of high density polyethylene and commingled post-consumer plastic waste. Fuel Process Technol. 1997;5:47–62.CrossRefGoogle Scholar
  21. 21.
    Ding WB, Tuntawiroon W, Liang J, Anderson LL. Depolymerization of waste plastics with coal over metal-loaded silica-alumina catalysts. Fuel Process Technol. 1996;49:49–63.CrossRefGoogle Scholar
  22. 22.
    Samuelsson LN, Moriana R, Babler MU, Ek M, Engvall K. Model-free rate expression for thermal decomposition processes: the case of microcrystalline cellulose pyrolysis. Fuel. 2015;143:438–47.CrossRefGoogle Scholar
  23. 23.
    Berčič G. The universality of Friedman’s isoconversional analysis results in a model-less prediction of thermodegradation profiles. Thermochim Acta. 2017;650:1–7.CrossRefGoogle Scholar
  24. 24.
    Hensen EJM, Poduval DG, Magusin PCMM, Coumans AE, van Veen JAR. Formation of acid sites in amorphous silica-alumina. J Catal. 2010;269:201–18.CrossRefGoogle Scholar
  25. 25.
    Eagle CD Jr. BNALib - A BASIC numerical analysis library for Personal Computers, ©1997-2002 (by C.D. Eagle Jr., Littleton (CO), USA, Scholar
  26. 26.
    Saha B, Ghoshal AK. Model-free kinetics analysis of waste PE sample. Thermochim Acta. 2006;451:27–33.CrossRefGoogle Scholar
  27. 27.
    Peterson JD, Vyazovkin S, Wight CA. kinetics of the thermal and thermo-oxidative degradation of polystyrene, polyethylene and poly(propylene). Macromol Chem Phys. 2001;202:775–84.CrossRefGoogle Scholar
  28. 28.
    Lyon RE. An integral method of nonisothermal kinetic analysis. Thermochim Acta. 1997;297:117–24.CrossRefGoogle Scholar
  29. 29.
    Boudart M, Djéga-Mariadassou G. Kinetics of Heterogeneous Catalytic Reactions, Princeton University Press 1984.Google Scholar
  30. 30.
    Bond GC, Keane MA, Kral H, Lercher JA. Compensation phenomena in heterogeneous catalysis: general principles and a possible explanation. Catal Rev Sci Eng. 2000;42(3):323–83.CrossRefGoogle Scholar
  31. 31.
    Ceamanos J, Mastral JF, Millera A, Aldea ME. Kinetics of pyrolysis of high density polyethylene. Comparison of isothermal and dynamic experiments. J Anal Appl Pyrol. 2002;65:93–110.CrossRefGoogle Scholar

Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2018

Authors and Affiliations

  • Gorazd Berčič
    • 1
    Email author
  • Petar Djinović
    • 2
  • Albin Pintar
    • 2
  1. 1.Department of Catalysis and Chemical Reaction EngineeringNational Institute of ChemistryLjubljanaSlovenia
  2. 2.Department for Environmental Sciences and EngineeringNational Institute of ChemistryLjubljanaSlovenia

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