{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T02:45:49Z","timestamp":1760237149179,"version":"build-2065373602"},"reference-count":23,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2020,3,2]],"date-time":"2020-03-02T00:00:00Z","timestamp":1583107200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Gels"],"abstract":"<jats:p>This study investigates the synthesis of formaldehyde-based xerogels using alternative aromatic precursors, with comparison to traditional resorcinol-formaldehyde analogues, in order to alter the chemical composition of the resulting gels. By replacing resorcinol with aromatic amine molecules, i.e., ammeline, melamine and melem, each expected to undergo similar reactions with formaldehyde as the substituted species, we found that for all substituted gels, at low additive contents, the gel structure was compromised and non-porous materials were formed, as opposed to the most abundant monomers, and therefore, these additives seem to act as impurities at low levels. Working towards higher additive contents, melem monomers exhibited low solubility (~5%), even at elevated temperatures, thereby limiting the range to which melem could act as a substitute, while melamine could be incorporated up to ~40% under acidic conditions, with enhanced microporosity over this range. Pure gels were successfully synthesised from ammeline, but their performance was inferior to resorcinol-formaldehyde gels, while melamine-formaldehyde analogues required acidic reaction conditions but shrank considerably on sub-critical drying, adversely affecting the gel properties and demonstrating their lack of potential as sorbents. This demonstrates the potential for the inclusion of aminated aromatics within resorcinol-based gel systems, however, only as partial substitutes and not complete replacements.<\/jats:p>","DOI":"10.3390\/gels6010008","type":"journal-article","created":{"date-parts":[[2020,3,2]],"date-time":"2020-03-02T07:50:53Z","timestamp":1583135453000},"page":"8","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Effect of Aromatic Amines on the Properties of Formaldehyde-Based Xerogels"],"prefix":"10.3390","volume":"6","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3916-0736","authenticated-orcid":false,"given":"David","family":"Martin","sequence":"first","affiliation":[{"name":"Department of Chemical and Process Engineering, University of Strathclyde, Glasgow, G1 1XJ, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5326-2408","authenticated-orcid":false,"given":"Martin","family":"Prostredn\u00fd","sequence":"additional","affiliation":[{"name":"Department of Chemical and Process Engineering, University of Strathclyde, Glasgow, G1 1XJ, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3915-8887","authenticated-orcid":false,"given":"Ashleigh J.","family":"Fletcher","sequence":"additional","affiliation":[{"name":"Department of Chemical and Process Engineering, University of Strathclyde, Glasgow, G1 1XJ, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,3,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"3221","DOI":"10.1007\/BF01139044","article-title":"Organic aerogels from the polycondensation of resorcinol with formaldehyde","volume":"24","author":"Pekala","year":"1989","journal-title":"J. Mater. Sci."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1016\/j.mtchem.2017.11.002","article-title":"Parametric study of factors affecting melamine-resorcinol-formaldehyde xerogels properties","volume":"7","author":"Principe","year":"2018","journal-title":"Mater. Today Chem."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"195","DOI":"10.1016\/j.mtchem.2018.09.006","article-title":"Decoupling microporosity and nitrogen content to optimize CO2 adsorption in melamine\u2013resorcinol\u2013formaldehyde xerogels","volume":"10","author":"Principe","year":"2018","journal-title":"Mater. Today Chem."},{"key":"ref_4","unstructured":"Pekala, R.W. (1992). Melamine-Formaldehyde Aerogels. (U.S. 5081163), Other: PPN: US 7-684051; Other: PPN: US 7-684051; Patent and Trademark Office, Washington, DC, USA, 20232 PTO English."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1002\/adma.200390020","article-title":"Preparation and Properties of Resorcinol\u2013Formaldehyde Organic and Carbon Gels","volume":"15","author":"Ritter","year":"2003","journal-title":"Adv. Mater."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"2887","DOI":"10.1002\/adma.201100283","article-title":"Advances in Tailoring Resorcinol-Formaldehyde Organic and Carbon Gels","volume":"23","year":"2011","journal-title":"Adv. Mater."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"403","DOI":"10.1080\/01496395.2015.1112398","article-title":"Removal of crystal violet from wastewater using resorcinol-formaldehyde carbon xerogels","volume":"51","year":"2016","journal-title":"Sep. Sci. Technol."},{"key":"ref_8","unstructured":"Yan, M., Wu, D., Wang, T., and Jia, D. (2019). Nitrogen, phosphorus co-doped carbon obtained from amino acid based resin xerogel as efficient electrode for supercapacitor. ACS Appl. Energy Mater."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"598","DOI":"10.1016\/j.msec.2019.03.033","article-title":"The use of functionalized carbon xerogels in cells growth","volume":"100","author":"Bosi","year":"2019","journal-title":"Mater. Sci. Eng."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"156","DOI":"10.1016\/S1872-5805(15)60181-0","article-title":"Effect of micropore and mesopore structure on CO2 adsorption by activated carbons from biomass","volume":"30","author":"Song","year":"2015","journal-title":"New Carbon Mater."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Prostredn\u00fd, M., Abduljalil, M., Mulheran, P., and Fletcher, A. (2018). Process Variable Optimization in the Manufacture of Resorcinol\u2013Formaldehyde Gel Materials. Gels, 4.","DOI":"10.3390\/gels4020036"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1016\/0022-3093(95)00082-8","article-title":"High-resolution transmission electron microscopy of the nanostructure of melamine-formaldehyde aerogels","volume":"186","author":"Ruben","year":"1995","journal-title":"J. Non-Crystal. Solids"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1051","DOI":"10.1515\/pac-2014-1117","article-title":"Physisorption of gases, with special reference to the evaluation of surface area and pore size distribution (IUPAC Technical Report)","volume":"87","author":"Thommes","year":"2015","journal-title":"Pure Appl. Chem."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2230","DOI":"10.1002\/(SICI)1521-3935(19991001)200:10<2230::AID-MACP2230>3.0.CO;2-U","article-title":"Storage stability of melamine-formaldehyde resin solutions, 1. The mechanism of instability","volume":"200","author":"Jahromi","year":"1999","journal-title":"Macromol. Chem. Phys."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"851","DOI":"10.1002\/recl.19590781102","article-title":"The reaction of phenol with formaldehyde: II. The ratio of ortho- and para-hydroxymethylphenol in the base-catalyzed hydroxymethylation of phenol","volume":"78","author":"Peer","year":"1959","journal-title":"Recl Trav. Chim. Pays-Bas"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"12052","DOI":"10.1002\/chem.201200723","article-title":"Use of Melem as a Nucleophilic Reagent to Form the Triphthalimide C6N7 (phthal)3\u2014New Targets and Prospects","volume":"18","author":"Schwarzer","year":"2012","journal-title":"Chem. A Eur. J."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Spasskaya, R.I., Finkel\u2019Shtein, A.I., Zil\u2019Berman, E.N., and Gal\u2019Perin, V.A. (1976). ChemInform Abstract: Reaction of melem with formaldehyde. Chem. Inform., 7.","DOI":"10.1002\/chin.197637269"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"476","DOI":"10.1002\/zaac.200900433","article-title":"Melemium Methylsulfonates HC6N7(NH2)3H2C6N7(NH2)3(SO3Me)3\u00b7H2O and H2C6N7(NH2)3(SO3Me)2\u00b7H2O","volume":"636","author":"Sattler","year":"2010","journal-title":"Z. Anorg. Allg. Chem."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"10288","DOI":"10.1021\/ja0357689","article-title":"Melem (2,5,8-Triamino-tri-s-triazine), an Important Intermediate during Condensation of Melamine Rings to Graphitic Carbon Nitride:\u2009 Synthesis, Structure Determination by X-ray Powder Diffractometry, Solid-State NMR, and Theoretical Studies","volume":"125","author":"Irran","year":"2003","journal-title":"J. Am. Chem. Soc."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"309","DOI":"10.1021\/ja01269a023","article-title":"Adsorption of gases in multimolecular layers","volume":"60","author":"Brunauer","year":"1938","journal-title":"J. Am. Chem. Soc."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1016\/S0167-2991(07)80008-5","article-title":"Is the BET equation applicable to microporous adsorbents?","volume":"160","author":"Rouquerol","year":"2007","journal-title":"Stud. Surf. Sci. Catal."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"319","DOI":"10.1016\/0021-9517(65)90307-6","article-title":"Studies on pore systems in catalysts: V. The t method","volume":"4","author":"Lippens","year":"1965","journal-title":"J. Catal."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"373","DOI":"10.1021\/ja01145a126","article-title":"The Determination of Pore Volume and Area Distributions in Porous Substances. I. Computations from Nitrogen Isotherms","volume":"73","author":"Barrett","year":"1951","journal-title":"J. Am. Chem. Soc."}],"container-title":["Gels"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2310-2861\/6\/1\/8\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T09:03:17Z","timestamp":1760173397000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2310-2861\/6\/1\/8"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,3,2]]},"references-count":23,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2020,3]]}},"alternative-id":["gels6010008"],"URL":"https:\/\/doi.org\/10.3390\/gels6010008","relation":{},"ISSN":["2310-2861"],"issn-type":[{"type":"electronic","value":"2310-2861"}],"subject":[],"published":{"date-parts":[[2020,3,2]]}}}