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https://hdl.handle.net/10216/103475
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DC Field | Value | Language |
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dc.creator | João M. M. Ferra | |
dc.creator | Ana Henriques | |
dc.creator | Adélio M. Mendes | |
dc.creator | Mário Rui N. Costa | |
dc.creator | Luísa H. Carvalho | |
dc.creator | Fernão D. Magalhães | |
dc.date.accessioned | 2022-09-07T07:33:17Z | - |
dc.date.available | 2022-09-07T07:33:17Z | - |
dc.date.issued | 2012 | |
dc.identifier.issn | 0021-8995 | |
dc.identifier.other | sigarra:62255 | |
dc.identifier.uri | https://hdl.handle.net/10216/103475 | - |
dc.description.abstract | This work discusses two processes for producing urea-formaldehyde (UF) resins. One is the alkaline-acid process, which has three steps: usually an alkaline methylolation followed by an acid condensation and finally the addition of a final amount of urea. The other process, the strongly acid process, consists of four steps, in which the first step involves a strongly acid condensation followed by an alkaline methylolation, a second condensation under a moderately acid pH and finally, methylolation and neutralization under a slight alkaline pH. Two resins were produced using the two above described processes. The molecular weight distribution (MWD) of the resins was monitored off-line by GPC/SEC and the final resins were characterized by GPC/SEC and HPLC. These studies showed that the two resins differ greatly in chemical structure, composition, viscosity, and reactivity. The monitoring of MWD indicated that the first condensation under a strongly acid environment leads to the production of a polymer with a distinctly different chemical structure, therefore increasing the flexibility of polymer synthesis and opening the way to the improvement of end-use properties. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 1764-1772, 2012 | |
dc.language.iso | eng | |
dc.relation | info:eu-repo/grantAgreement/FCT - Fundação para a Ciência e a Tecnologia/Programa de Financiamento Plurianual de Unidades de I&D/PEst-C/EQB/LA0020/2011/Projeto Estratégico-LA 20 - 2011-2012/LA 20 | |
dc.rights | restrictedAccess | |
dc.subject | Ciências Tecnológicas, Química | |
dc.subject | Technological sciences, Chemical sciences | |
dc.title | Comparison of UF synthesis by alkaline-acid and strongly acid processes | |
dc.type | Artigo em Revista Científica Internacional | |
dc.contributor.uporto | Faculdade de Engenharia | |
dc.identifier.doi | 10.1002/app.34642 | |
dc.identifier.authenticus | P-002-D3N | |
dc.subject.fos | Ciências exactas e naturais::Química | |
dc.subject.fos | Natural sciences::Chemical sciences | |
Appears in Collections: | FEUP - Artigo em Revista Científica Internacional |
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File | Description | Size | Format | |
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62255.pdf Restricted Access | Artigo original publicado | 721.77 kB | Adobe PDF | Request a copy from the Author(s) |
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