Study of the synthesis parameters of a urea-formaldehyde resin synthesized according to alkaline-acid process
Autor(a) principal: | |
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Data de Publicação: | 2020 |
Outros Autores: | , , , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10773/37515 |
Resumo: | This paper presents a study of two crucial synthesis parameters of the alkaline-acid process of UF resin synthesis: condensation formaldehyde/urea (F/U) molar ratio and U feed rate during the methylolation step. The differences in the polymeric structures and the performance of the ensuing resins on particleboards (PBs) properties were analyzed and compared with a standard resin. The molecular weight distribution of the resins was monitored by gel permeation chromatography/size exclusion chromatography (GPC/SEC) and the unreacted oligomers by high-performance liquid chromatography (HPLC). The PBs produced were analyzed following European standards for mechanical tests and formaldehyde emission. The data obtained were also submitted to a statistical analysis. The results obtained showed that the use of low molar ratios yield higher internal bond strength (IB) values and lower formaldehyde emissions (F). In turn, the effect of urea feed rate during the methylolation step on IB values depends on the F/UII molar ratio used: (i) a reduction for the higher final molar ratio used, and no effect for the lowest final molar ratio used. Moreover, the statistical analysis carried out showed that F/UII molar ratio has significance on almost all of the resins’ characteristics. The resin used as standard yielded the best results when the final F/U molar ratio was 1.10 and the resulting PBs presented values of internal bond (IB) of 0.51 N mm−2 and formaldehyde content (F) of 5.1 mg/100 g o.d.b., complying with the market requirements. Additionally, the effect of resin ageing was also studied and the PBs prepared using the best resin upon fifteen days of its production presented similar IB values and even lower F content in relation to those obtained using fresh resin. |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Study of the synthesis parameters of a urea-formaldehyde resin synthesized according to alkaline-acid processAdhesives for woodResin-based compositesWood and wood compositesFormaldehyde/urea (F/U) molar ratioUrea (U) feed rateThis paper presents a study of two crucial synthesis parameters of the alkaline-acid process of UF resin synthesis: condensation formaldehyde/urea (F/U) molar ratio and U feed rate during the methylolation step. The differences in the polymeric structures and the performance of the ensuing resins on particleboards (PBs) properties were analyzed and compared with a standard resin. The molecular weight distribution of the resins was monitored by gel permeation chromatography/size exclusion chromatography (GPC/SEC) and the unreacted oligomers by high-performance liquid chromatography (HPLC). The PBs produced were analyzed following European standards for mechanical tests and formaldehyde emission. The data obtained were also submitted to a statistical analysis. The results obtained showed that the use of low molar ratios yield higher internal bond strength (IB) values and lower formaldehyde emissions (F). In turn, the effect of urea feed rate during the methylolation step on IB values depends on the F/UII molar ratio used: (i) a reduction for the higher final molar ratio used, and no effect for the lowest final molar ratio used. Moreover, the statistical analysis carried out showed that F/UII molar ratio has significance on almost all of the resins’ characteristics. The resin used as standard yielded the best results when the final F/U molar ratio was 1.10 and the resulting PBs presented values of internal bond (IB) of 0.51 N mm−2 and formaldehyde content (F) of 5.1 mg/100 g o.d.b., complying with the market requirements. Additionally, the effect of resin ageing was also studied and the PBs prepared using the best resin upon fifteen days of its production presented similar IB values and even lower F content in relation to those obtained using fresh resin.Elsevier2023-05-05T08:08:01Z2020-10-01T00:00:00Z2020-10info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfhttp://hdl.handle.net/10773/37515eng0143-749610.1016/j.ijadhadh.2020.102646Gonçalves, CarolinaPereira, JoãoPaiva, NádiaFerra, JoãoMartins, JorgeMagalhães, FernãoBarros-Timmons, AnaCarvalho, Luísainfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-02-22T12:12:31Zoai:ria.ua.pt:10773/37515Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T03:08:08.454131Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Study of the synthesis parameters of a urea-formaldehyde resin synthesized according to alkaline-acid process |
title |
Study of the synthesis parameters of a urea-formaldehyde resin synthesized according to alkaline-acid process |
spellingShingle |
Study of the synthesis parameters of a urea-formaldehyde resin synthesized according to alkaline-acid process Gonçalves, Carolina Adhesives for wood Resin-based composites Wood and wood composites Formaldehyde/urea (F/U) molar ratio Urea (U) feed rate |
title_short |
Study of the synthesis parameters of a urea-formaldehyde resin synthesized according to alkaline-acid process |
title_full |
Study of the synthesis parameters of a urea-formaldehyde resin synthesized according to alkaline-acid process |
title_fullStr |
Study of the synthesis parameters of a urea-formaldehyde resin synthesized according to alkaline-acid process |
title_full_unstemmed |
Study of the synthesis parameters of a urea-formaldehyde resin synthesized according to alkaline-acid process |
title_sort |
Study of the synthesis parameters of a urea-formaldehyde resin synthesized according to alkaline-acid process |
author |
Gonçalves, Carolina |
author_facet |
Gonçalves, Carolina Pereira, João Paiva, Nádia Ferra, João Martins, Jorge Magalhães, Fernão Barros-Timmons, Ana Carvalho, Luísa |
author_role |
author |
author2 |
Pereira, João Paiva, Nádia Ferra, João Martins, Jorge Magalhães, Fernão Barros-Timmons, Ana Carvalho, Luísa |
author2_role |
author author author author author author author |
dc.contributor.author.fl_str_mv |
Gonçalves, Carolina Pereira, João Paiva, Nádia Ferra, João Martins, Jorge Magalhães, Fernão Barros-Timmons, Ana Carvalho, Luísa |
dc.subject.por.fl_str_mv |
Adhesives for wood Resin-based composites Wood and wood composites Formaldehyde/urea (F/U) molar ratio Urea (U) feed rate |
topic |
Adhesives for wood Resin-based composites Wood and wood composites Formaldehyde/urea (F/U) molar ratio Urea (U) feed rate |
description |
This paper presents a study of two crucial synthesis parameters of the alkaline-acid process of UF resin synthesis: condensation formaldehyde/urea (F/U) molar ratio and U feed rate during the methylolation step. The differences in the polymeric structures and the performance of the ensuing resins on particleboards (PBs) properties were analyzed and compared with a standard resin. The molecular weight distribution of the resins was monitored by gel permeation chromatography/size exclusion chromatography (GPC/SEC) and the unreacted oligomers by high-performance liquid chromatography (HPLC). The PBs produced were analyzed following European standards for mechanical tests and formaldehyde emission. The data obtained were also submitted to a statistical analysis. The results obtained showed that the use of low molar ratios yield higher internal bond strength (IB) values and lower formaldehyde emissions (F). In turn, the effect of urea feed rate during the methylolation step on IB values depends on the F/UII molar ratio used: (i) a reduction for the higher final molar ratio used, and no effect for the lowest final molar ratio used. Moreover, the statistical analysis carried out showed that F/UII molar ratio has significance on almost all of the resins’ characteristics. The resin used as standard yielded the best results when the final F/U molar ratio was 1.10 and the resulting PBs presented values of internal bond (IB) of 0.51 N mm−2 and formaldehyde content (F) of 5.1 mg/100 g o.d.b., complying with the market requirements. Additionally, the effect of resin ageing was also studied and the PBs prepared using the best resin upon fifteen days of its production presented similar IB values and even lower F content in relation to those obtained using fresh resin. |
publishDate |
2020 |
dc.date.none.fl_str_mv |
2020-10-01T00:00:00Z 2020-10 2023-05-05T08:08:01Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10773/37515 |
url |
http://hdl.handle.net/10773/37515 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
0143-7496 10.1016/j.ijadhadh.2020.102646 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Elsevier |
publisher.none.fl_str_mv |
Elsevier |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
instname_str |
Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
instacron_str |
RCAAP |
institution |
RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
collection |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
repository.name.fl_str_mv |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
repository.mail.fl_str_mv |
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1799137735079886848 |