Polymer Bulletin

, Volume 76, Issue 6, pp 2931–2944 | Cite as

Microwave-assisted esterification step of poly(ethylene terephthalate) (PET) synthesis through ethylene glycol and terephthalic acid

  • Ana Christy Espinosa-López
  • Carlos Alberto Ávila-OrtaEmail author
  • Francisco Javier Medellín-Rodríguez
  • Pablo González-Morones
  • Carlos Alberto Gallardo-Vega
  • Patricia Adriana De León-Martínez
  • Maribel Navarro-Rosales
  • Janett Anaid Valdez-Garza
Original Paper


The esterification step during poly(ethylene terephthalate) (PET) polymerization was studied using ethylene glycol (EG) and terephthalic acid (TPA), together with microwave radiation in a closed system. First, the effects of temperature and molar ratio EG/TPA on the number-average molecular weight (\( \bar{M}_{n} \)) were determined. The reaction products were then identified using Fourier transform infrared spectroscopy and proton nuclear magnetic resonance (1H NMR). The molecular weight was determined through gel permeation chromatography, and the thermal behavior was obtained with differential scanning calorimetry. The PET number-average molecular weight, \( \bar{M}_{n} \), ranged between 308 and 1504 g mol−1, which were close values regarding those produced after 240–300 min under conventional heating. The reaction products were obtained after 45 min of reaction without water or EG removal. It was also determined that temperature and the molar EG/TPA ratio were correlated with \( \bar{M}_{n} \), as an indication of the variation of the solubility of TPA in the reaction mixture.


Microwave-assisted polymerization Esterification Polyesters Poly(ethylene terephthalate) (PET) 



The authors thank Consejo Nacional de Ciencia y Tecnología (CONACYT from Mexico) for the funding through Grants CB-2014-01 241960 and CB-2009 132699. The authors are also grateful to Silvia Torres Rincón (from CIQA, México), Olga Dávalos Montoya (from Autonomous University of San Luis Potosí, México) and Judith Nazaret Cabello Romero (CIQA) for their technical support and Dr. Roberto Yañez Macías (CIQA, México) for his valuable support during manuscript preparation. The support of CONACYT through Grant 294030 (LANIAUTO) is greatly appreciated.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Supplementary material

289_2018_2521_MOESM1_ESM.docx (881 kb)
Supplementary material 1 (DOCX 881 kb)


  1. 1.
    Rieckman T, Völker S (2003) Modern polyesters: chemistry and technology of polyesters and copolyesters. In: Scheirs J, Long TE (eds) Modern polyesters: chemistry and technology of polyesters and copolyesters. Wiley, New York, pp 31–104Google Scholar
  2. 2.
    Yamada T (1992) A mathematical model for a continuous esterification process with recycle between terephthalic acid and ethylene glycol. J Appl Polym Sci 45:1919–1936. CrossRefGoogle Scholar
  3. 3.
    Tremblay DA (1999) Using simulation technology to improve profitability in the polymer industry. American Institute of Chemical EngineersGoogle Scholar
  4. 4.
    Ravindranath K, Mashelkar RA (1981) Modeling of poly(ethylene terephthalate) reactors. 1. A semibatch ester interchange reactor. J Appl Polym Sci 26:3179–3204CrossRefGoogle Scholar
  5. 5.
    Patel H, Feix G, Schomäcker R (2007) Modeling of semibatch esterification process for poly(ethylene terephthalate) synthesis. Macromol React Eng 1:502–512. CrossRefGoogle Scholar
  6. 6.
    Baranova TL, Kremer EB (1978) Solution of terephthalic acid in the reaction system terephthalic acid-ethylene glycol-esterification products. Fibre Chem 9:333–336. CrossRefGoogle Scholar
  7. 7.
    Kang C-K, Lee BC, Ihm DW (1996) Modeling of semibatch direct esterification reactor for poly(ethylene terephthalate) synthesis. J Appl Polym Sci 60:2007–2015CrossRefGoogle Scholar
  8. 8.
    Yamada T, Imamura Y, Makimura O (1985) A mathematical model for computer simulation of a direct continuos esterification process between terephthalic acid and ethylene glycol: Part 1. Model development. Polym Eng Sci 25:788–795CrossRefGoogle Scholar
  9. 9.
    Yamada T (1994) Influence of reaction temperature on direct esterifications in a continuous recycling process between terephthalic acid and ethylene glycol. J Appl Polym Sci 51:1323–1337CrossRefGoogle Scholar
  10. 10.
    Chen J-W, Chen L-W (1998) The kinetics of diethylene glycol formation in the preparation of polyethylene terephthalate. J Polym Sci Part A Polym Chem 36:3073–3080CrossRefGoogle Scholar
  11. 11.
    Siddiqui MN, Achilias DS, Redhwi HH et al (2010) Hydrolytic depolymerization of PET in a microwave reactor. Macromol Mater Eng 295:575–584. CrossRefGoogle Scholar
  12. 12.
    Leonelli C, Mason TJ (2010) Microwave and ultrasonic processing: now a realistic option for industry. Chem Eng Process Process Intensif 49:885–900. CrossRefGoogle Scholar
  13. 13.
    Komorowska-Durka M, Dimitrakis G, Bogdał D et al (2015) A concise review on microwave-assisted polycondensation reactions and curing of polycondensation polymers with focus on the effect of process conditions. Chem Eng J 264:633–644. CrossRefGoogle Scholar
  14. 14.
    Kempe K, Becer CR, Schubert US (2011) Microwave-assisted polymerizations: recent status and future perspectives. Macromolecules 44:5825–5842. CrossRefGoogle Scholar
  15. 15.
    Wiesbrock F, Hoogenboom R, Schubert US (2004) Microwave-assisted polymer synthesis: state-of-the-art and future perspectives. Macromol Rapid Commun 25:1739–1764. CrossRefGoogle Scholar
  16. 16.
    Wiesbrock F, Hoogenboom R, Abeln CH, Schubert US (2004) Single-mode microwave ovens as new reaction devices: accelerating the living polymerization of 2-ethyl-2-oxazoline. Macromol Rapid Commun 25:1895–1899. CrossRefGoogle Scholar
  17. 17.
    Herrero M, Martínez-Gallegos S, Labajos FM, Rives V (2011) Layered double hydroxide/polyethylene terephthalate nanocomposites. Influence of the intercalated LDH anion and the type of polymerization heating method. J Solid State Chem 184:2862–2869. CrossRefGoogle Scholar
  18. 18.
    Mallon FK, Ray WH (1998) Enhancement of solid-state polymerization with microwave energy. J Appl Polym Sci 69:1203–1212CrossRefGoogle Scholar
  19. 19.
    Nagahata R, Sugiyama J, Velmathi S et al (2004) Synthesis of poly(ethylene terephthalate-co-isophthalate) by copolymerization of ethylene isophthalate cyclic dimer and bis(2-hydroxyethyl) terephthalate. Polym J 36:483–488. CrossRefGoogle Scholar
  20. 20.
    Ravindranath K, Mashelkar RA (1982) Modeling of poly(ethylene terephthalate) reactors: 5. A continuous prepolymerization process. Polym Eng Sci 22:619–627CrossRefGoogle Scholar
  21. 21.
    Yamada T (1989) Effect of diantimony trioxide on direct esterification between terephthalic acid and ethylene glycol. J Appl Polym Sci 37:1821–1835. CrossRefGoogle Scholar
  22. 22.
    Mazloom M, Rafizadeh M, Haddadi-Asl V, Pakniat M (2007) Synthesis and mathematical modelling of polyethylene terephthalate via direct esterification in a laboratory scale unit. Iran Polym J 16:587–596Google Scholar
  23. 23.
    Apicella B, Di Serio M, Fiocca L et al (1998) Kinetic and catalytic aspects of the formation of poly(ethylene terephthalate) (PET) investigated with model molecules. J Appl Polym Sci 69:2423–2433CrossRefGoogle Scholar
  24. 24.
    Kim J-Y, Kim H-Y, Yeo Y-K (2001) Identification of kinetics of direct esterification reactions for PET synthesis based on a genetic algorithm. Korean J Chem Eng 18:432–441. CrossRefGoogle Scholar
  25. 25.
    Xi G, Lu M, Sun C (2005) Study on depolymerization of waste polyethylene terephthalate into monomer of bis(2-hydroxyethyl terephthalate). Polym Degrad Stab 87:117–120. CrossRefGoogle Scholar
  26. 26.
    Achilias DS, Redhwi HH, Siddiqui MN et al (2010) Glycolytic depolymerization of PET waste in a microwave reactor. J Appl Polym Sci 118:3066–3073CrossRefGoogle Scholar
  27. 27.
    Pingale ND, Shukla SR (2008) Microwave assisted ecofriendly recycling of poly(ethylene terephthalate) bottle waste. Eur Polym J 44:4151–4156. CrossRefGoogle Scholar
  28. 28.
    Yamada T, Imamura Y, Makumira O (1988) A mathematical model for computer simulation of a direct continuous esterification process between terephthalic acid and ethylene glycol. Polym Eng Sci 28:385–392. CrossRefGoogle Scholar
  29. 29.
    Yang KS, An KH, Choi CN et al (1996) Solubility and esterification kinetics of terephthalic acid in ethylene glycol. The effects of functional groups. J Appl Polym Sci 60:1033–1039CrossRefGoogle Scholar
  30. 30.
    Martínez-Gallegos S, Herrero M, Rives V (2008) In Situ microwave-assisted polymerization of polyethylene terephtalate in layered double hydroxides. J Appl Polym Sci 109:1388–1394. CrossRefGoogle Scholar
  31. 31.
    Šašic S, Amari T, Siesler HW, Ozaki Y (2001) Polycondensation reaction of bis(hydroxyethylterephthalate)—self modeling curve resolution analysis of on-line ATR/FT-IR spectra. Appl Spectrosc 55:1181–1191. CrossRefGoogle Scholar
  32. 32.
    García-Gaitánn B, Pérez-González MDP, Martínez-Richa A et al (2004) Segmented block copolymers of poly(ethylene glycol) and poly(ethylene terephthalate). J Polym Sci Part A Polym Chem 42:4448–4457. CrossRefGoogle Scholar
  33. 33.
    Martínez De Ilarduya A, Muñoz-Guerra S (2014) Chemical structure and microstructure of poly (alkylene terephthalate)s, their copolyesters, and their blends as studied by NMR. Macromol Chem Phys 215:2138–2160CrossRefGoogle Scholar
  34. 34.
    Petiaud R, Waton H, Pham Q-T (1992) A 1H and 13C NMR study of the products form direct polyesterification of ethylene glycol and terephthalic acid. Polymer (Guildf) 33:3155–3161CrossRefGoogle Scholar
  35. 35.
    Avila-Orta CA, Medellín-Rodríguez FJ, Wang Z-G et al (2003) On the nature of multiple melting in poly(ethylene terephthalate) (PET) and its copolymers with cyclohexylene dimethylene terephthalate (PET/CT). Polymer 44:1527–1535CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Ana Christy Espinosa-López
    • 1
  • Carlos Alberto Ávila-Orta
    • 1
    Email author
  • Francisco Javier Medellín-Rodríguez
    • 2
  • Pablo González-Morones
    • 1
  • Carlos Alberto Gallardo-Vega
    • 1
  • Patricia Adriana De León-Martínez
    • 3
  • Maribel Navarro-Rosales
    • 1
  • Janett Anaid Valdez-Garza
    • 1
  1. 1.Advanced Materials DepartmentCentro de Investigación en Química AplicadaSaltilloMexico
  2. 2.Centro de Investigación y Estudios de Posgrado, Facultad de Ciencias QuímicasUniversidad Autónoma de San Luis PotosíSan Luis PotosíMexico
  3. 3.Universidad Autónoma de CoahuilaSaltilloMexico

Personalised recommendations