Online monitoring of synthesis and curing of phenol-formaldehyde resol resins by Raman spectroscopy

Janne. Monni, Pentti Niemelä, Leila Alvila, Tuula T. Pakkanen (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

23 Citations (Scopus)

Abstract

The synthesis and curing of phenol–formaldehyde resol resins were monitored online by Raman spectroscopy. The synthesis of the resins (F/P 2.0, alkalinity 4.5 wt%) was studied at rising temperature (40–90 °C) for 90 min and at constant temperatures (80 °C, 90 °C, 100 °C, and 110 °C) for 120 min. The progress of the curing was investigated isothermally (80 °C, 90 °C, 100 °C, and 110 °C) for 120 min for three resins with different degrees of condensation. The synthesis and curing of the resins were started in the reactor and the advancement of the methylolation and condensation reactions was followed through the window of the reactor in the wave number region of 2000–400 cm−1 with use of a fiber optic probe for the data collection. The Raman spectra of six model compounds (formaldehyde, phenol, 2-hydroxybenzyl alcohol, 4-hydroxybenzyl alcohol, 2-benzylphenol, and 4-benzylphenol) were analyzed to facilitate the interpretation of the spectra of the resins. The consumptions of free phenol and free formaldehyde, as well as the progress of the methylolation and condensation reactions were easily monitored by following the changes in intensity of the characteristic Raman bands. The results for the cured resins obtained by Raman spectroscopy were in good agreement with the structures and residual reactivities studied by CP/MAS 13C NMR spectroscopy and differential scanning calorimetry (DSC), respectively. The results of the study show Raman spectroscopy to be a promising tool for the online monitoring and control of phenol–formaldehyde resol resin synthesis and curing; in addition, Raman spectroscopy offers an effective and fast method for structural study of the solid state resins.
Original languageEnglish
Pages (from-to)3865 - 3874
Number of pages10
JournalPolymer
Volume49
Issue number18
DOIs
Publication statusPublished - 2008
MoE publication typeA1 Journal article-refereed

Fingerprint

Formaldehyde
Phenols
Curing
Raman spectroscopy
Resins
Monitoring
Condensation reactions
Phenol
Alcohols
phenol-formaldehyde resin
Alkalinity
Fiber optics
Nuclear magnetic resonance spectroscopy
Raman scattering
Differential scanning calorimetry
Condensation
Temperature

Keywords

  • Phenol-formaldehyde resin synthesis
  • Raman spectroscopy
  • Online

Cite this

Monni, Janne. ; Niemelä, Pentti ; Alvila, Leila ; Pakkanen, Tuula T. / Online monitoring of synthesis and curing of phenol-formaldehyde resol resins by Raman spectroscopy. In: Polymer. 2008 ; Vol. 49, No. 18. pp. 3865 - 3874.
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abstract = "The synthesis and curing of phenol–formaldehyde resol resins were monitored online by Raman spectroscopy. The synthesis of the resins (F/P 2.0, alkalinity 4.5 wt{\%}) was studied at rising temperature (40–90 °C) for 90 min and at constant temperatures (80 °C, 90 °C, 100 °C, and 110 °C) for 120 min. The progress of the curing was investigated isothermally (80 °C, 90 °C, 100 °C, and 110 °C) for 120 min for three resins with different degrees of condensation. The synthesis and curing of the resins were started in the reactor and the advancement of the methylolation and condensation reactions was followed through the window of the reactor in the wave number region of 2000–400 cm−1 with use of a fiber optic probe for the data collection. The Raman spectra of six model compounds (formaldehyde, phenol, 2-hydroxybenzyl alcohol, 4-hydroxybenzyl alcohol, 2-benzylphenol, and 4-benzylphenol) were analyzed to facilitate the interpretation of the spectra of the resins. The consumptions of free phenol and free formaldehyde, as well as the progress of the methylolation and condensation reactions were easily monitored by following the changes in intensity of the characteristic Raman bands. The results for the cured resins obtained by Raman spectroscopy were in good agreement with the structures and residual reactivities studied by CP/MAS 13C NMR spectroscopy and differential scanning calorimetry (DSC), respectively. The results of the study show Raman spectroscopy to be a promising tool for the online monitoring and control of phenol–formaldehyde resol resin synthesis and curing; in addition, Raman spectroscopy offers an effective and fast method for structural study of the solid state resins.",
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Online monitoring of synthesis and curing of phenol-formaldehyde resol resins by Raman spectroscopy. / Monni, Janne.; Niemelä, Pentti; Alvila, Leila; Pakkanen, Tuula T. (Corresponding Author).

In: Polymer, Vol. 49, No. 18, 2008, p. 3865 - 3874.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Online monitoring of synthesis and curing of phenol-formaldehyde resol resins by Raman spectroscopy

AU - Monni, Janne.

AU - Niemelä, Pentti

AU - Alvila, Leila

AU - Pakkanen, Tuula T.

PY - 2008

Y1 - 2008

N2 - The synthesis and curing of phenol–formaldehyde resol resins were monitored online by Raman spectroscopy. The synthesis of the resins (F/P 2.0, alkalinity 4.5 wt%) was studied at rising temperature (40–90 °C) for 90 min and at constant temperatures (80 °C, 90 °C, 100 °C, and 110 °C) for 120 min. The progress of the curing was investigated isothermally (80 °C, 90 °C, 100 °C, and 110 °C) for 120 min for three resins with different degrees of condensation. The synthesis and curing of the resins were started in the reactor and the advancement of the methylolation and condensation reactions was followed through the window of the reactor in the wave number region of 2000–400 cm−1 with use of a fiber optic probe for the data collection. The Raman spectra of six model compounds (formaldehyde, phenol, 2-hydroxybenzyl alcohol, 4-hydroxybenzyl alcohol, 2-benzylphenol, and 4-benzylphenol) were analyzed to facilitate the interpretation of the spectra of the resins. The consumptions of free phenol and free formaldehyde, as well as the progress of the methylolation and condensation reactions were easily monitored by following the changes in intensity of the characteristic Raman bands. The results for the cured resins obtained by Raman spectroscopy were in good agreement with the structures and residual reactivities studied by CP/MAS 13C NMR spectroscopy and differential scanning calorimetry (DSC), respectively. The results of the study show Raman spectroscopy to be a promising tool for the online monitoring and control of phenol–formaldehyde resol resin synthesis and curing; in addition, Raman spectroscopy offers an effective and fast method for structural study of the solid state resins.

AB - The synthesis and curing of phenol–formaldehyde resol resins were monitored online by Raman spectroscopy. The synthesis of the resins (F/P 2.0, alkalinity 4.5 wt%) was studied at rising temperature (40–90 °C) for 90 min and at constant temperatures (80 °C, 90 °C, 100 °C, and 110 °C) for 120 min. The progress of the curing was investigated isothermally (80 °C, 90 °C, 100 °C, and 110 °C) for 120 min for three resins with different degrees of condensation. The synthesis and curing of the resins were started in the reactor and the advancement of the methylolation and condensation reactions was followed through the window of the reactor in the wave number region of 2000–400 cm−1 with use of a fiber optic probe for the data collection. The Raman spectra of six model compounds (formaldehyde, phenol, 2-hydroxybenzyl alcohol, 4-hydroxybenzyl alcohol, 2-benzylphenol, and 4-benzylphenol) were analyzed to facilitate the interpretation of the spectra of the resins. The consumptions of free phenol and free formaldehyde, as well as the progress of the methylolation and condensation reactions were easily monitored by following the changes in intensity of the characteristic Raman bands. The results for the cured resins obtained by Raman spectroscopy were in good agreement with the structures and residual reactivities studied by CP/MAS 13C NMR spectroscopy and differential scanning calorimetry (DSC), respectively. The results of the study show Raman spectroscopy to be a promising tool for the online monitoring and control of phenol–formaldehyde resol resin synthesis and curing; in addition, Raman spectroscopy offers an effective and fast method for structural study of the solid state resins.

KW - Phenol-formaldehyde resin synthesis

KW - Raman spectroscopy

KW - Online

U2 - 10.1016/j.polymer.2008.06.050

DO - 10.1016/j.polymer.2008.06.050

M3 - Article

VL - 49

SP - 3865

EP - 3874

JO - Polymer

JF - Polymer

SN - 0032-3861

IS - 18

ER -