Process variable optimization in the manufacture of resorcinol–formaldehyde gel materials

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Abstract

Influence of process parameters of resorcinol-formaldehyde xerogel manufacture on final gel structure was studied, including solids content, preparation/drying temperature, solvent exchange, and drying method. Xerogels produced using a range of solids content between 10 to 40w/v% shows improved textural character up to 30w/v% with a subsequent decrease. Preparation/drying temperature shows a minimal threshold temperature of 55 °C is required to obtain a viable gel structure, with minimal impact on gel properties for further thermal increase. Improving the solvent exchange method by splitting the same amount of acetone used in this phase over the period of solvent exchange, rather than in a single application, shows an increase in total pore volume and average pore diameter, suggesting less shrinkage occurring during drying when using the improved method. Finally, comparing samples dried under vacuum and at ambient pressure, there seems to be less shrinkage when using vacuum drying compared to ambient drying, but these changes are insubstantial. Therefore, of the process parameters investigated, improved solvent exchange seems the most significant, and it is recommended that, economically, gels are produced using a solids content of 20w/v% at a temperature in excess of 55 °C, with regular solvent replenishment in the exchange step followed by ambient drying.
LanguageEnglish
Article number36
Number of pages14
JournalGels
Volume4
Issue number2
DOIs
Publication statusPublished - 17 Apr 2018

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Formaldehyde
Drying
Gels
Xerogels
Vacuum
Temperature
Acetone
resorcinol

Keywords

  • xerogel
  • BET
  • BJH
  • temperature
  • solids content
  • drying
  • solvent exchange

Cite this

@article{60daa156ddc6403eb9f8a0553b8e7a3c,
title = "Process variable optimization in the manufacture of resorcinol–formaldehyde gel materials",
abstract = "Influence of process parameters of resorcinol-formaldehyde xerogel manufacture on final gel structure was studied, including solids content, preparation/drying temperature, solvent exchange, and drying method. Xerogels produced using a range of solids content between 10 to 40w/v{\%} shows improved textural character up to 30w/v{\%} with a subsequent decrease. Preparation/drying temperature shows a minimal threshold temperature of 55 °C is required to obtain a viable gel structure, with minimal impact on gel properties for further thermal increase. Improving the solvent exchange method by splitting the same amount of acetone used in this phase over the period of solvent exchange, rather than in a single application, shows an increase in total pore volume and average pore diameter, suggesting less shrinkage occurring during drying when using the improved method. Finally, comparing samples dried under vacuum and at ambient pressure, there seems to be less shrinkage when using vacuum drying compared to ambient drying, but these changes are insubstantial. Therefore, of the process parameters investigated, improved solvent exchange seems the most significant, and it is recommended that, economically, gels are produced using a solids content of 20w/v{\%} at a temperature in excess of 55 °C, with regular solvent replenishment in the exchange step followed by ambient drying.",
keywords = "xerogel, BET, BJH, temperature , solids content, drying, solvent exchange",
author = "Martin Prostredn{\'y} and Abduljalil, {Mohammed G. M.} and Mulheran, {Paul A.} and Fletcher, {Ashleigh J.}",
year = "2018",
month = "4",
day = "17",
doi = "10.3390/gels4020036",
language = "English",
volume = "4",
journal = "Gels",
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T1 - Process variable optimization in the manufacture of resorcinol–formaldehyde gel materials

AU - Prostredný, Martin

AU - Abduljalil, Mohammed G. M.

AU - Mulheran, Paul A.

AU - Fletcher, Ashleigh J.

PY - 2018/4/17

Y1 - 2018/4/17

N2 - Influence of process parameters of resorcinol-formaldehyde xerogel manufacture on final gel structure was studied, including solids content, preparation/drying temperature, solvent exchange, and drying method. Xerogels produced using a range of solids content between 10 to 40w/v% shows improved textural character up to 30w/v% with a subsequent decrease. Preparation/drying temperature shows a minimal threshold temperature of 55 °C is required to obtain a viable gel structure, with minimal impact on gel properties for further thermal increase. Improving the solvent exchange method by splitting the same amount of acetone used in this phase over the period of solvent exchange, rather than in a single application, shows an increase in total pore volume and average pore diameter, suggesting less shrinkage occurring during drying when using the improved method. Finally, comparing samples dried under vacuum and at ambient pressure, there seems to be less shrinkage when using vacuum drying compared to ambient drying, but these changes are insubstantial. Therefore, of the process parameters investigated, improved solvent exchange seems the most significant, and it is recommended that, economically, gels are produced using a solids content of 20w/v% at a temperature in excess of 55 °C, with regular solvent replenishment in the exchange step followed by ambient drying.

AB - Influence of process parameters of resorcinol-formaldehyde xerogel manufacture on final gel structure was studied, including solids content, preparation/drying temperature, solvent exchange, and drying method. Xerogels produced using a range of solids content between 10 to 40w/v% shows improved textural character up to 30w/v% with a subsequent decrease. Preparation/drying temperature shows a minimal threshold temperature of 55 °C is required to obtain a viable gel structure, with minimal impact on gel properties for further thermal increase. Improving the solvent exchange method by splitting the same amount of acetone used in this phase over the period of solvent exchange, rather than in a single application, shows an increase in total pore volume and average pore diameter, suggesting less shrinkage occurring during drying when using the improved method. Finally, comparing samples dried under vacuum and at ambient pressure, there seems to be less shrinkage when using vacuum drying compared to ambient drying, but these changes are insubstantial. Therefore, of the process parameters investigated, improved solvent exchange seems the most significant, and it is recommended that, economically, gels are produced using a solids content of 20w/v% at a temperature in excess of 55 °C, with regular solvent replenishment in the exchange step followed by ambient drying.

KW - xerogel

KW - BET

KW - BJH

KW - temperature

KW - solids content

KW - drying

KW - solvent exchange

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