Effects of Alcell Lignin Methylolation and Lignin Adding Stage on Lignin-Based Phenolic Adhesives

To investigate the effects of lignin methylolation and lignin adding stage on the resulted lignin-based phenolic adhesives, Alcell lignin activated with NaOH (AL) or methylolation (ML) was integrated into the phenolic adhesives system by replacing phenol at various adhesive synthesis stages or direc...

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Autores principales: Xianbin Ai, Shanghuan Feng, Tao Shui, Himant Kakkar, Chunbao Charles Xu
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Lenguaje:EN
Publicado: MDPI AG 2021
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Acceso en línea:https://doaj.org/article/995da34084e442c0a9cfc2b823135447
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spelling oai:doaj.org-article:995da34084e442c0a9cfc2b8231354472021-11-25T18:27:03ZEffects of Alcell Lignin Methylolation and Lignin Adding Stage on Lignin-Based Phenolic Adhesives10.3390/molecules262267621420-3049https://doaj.org/article/995da34084e442c0a9cfc2b8231354472021-11-01T00:00:00Zhttps://www.mdpi.com/1420-3049/26/22/6762https://doaj.org/toc/1420-3049To investigate the effects of lignin methylolation and lignin adding stage on the resulted lignin-based phenolic adhesives, Alcell lignin activated with NaOH (AL) or methylolation (ML) was integrated into the phenolic adhesives system by replacing phenol at various adhesive synthesis stages or directly co-polymerizing with phenolic adhesives. Lignin integration into phenolic adhesives greatly increased the viscosity of the resultant adhesives, regardless of lignin methylolation or adding stage. ML introduction at the second stage of adhesive synthesis led to much bigger viscosity than ML or AL introduction into phenolic adhesives at any other stages. Lignin methylolation and lignin adding stage did not affect the thermal stability of lignin based phenolic adhesives, even though lignin-based adhesives were less thermally stable than NPF. Typical three-stage degradation characteristics were also observed on all the lignin-based phenolic adhesives. Three-ply plywoods can be successfully laminated with lignin based adhesives, and it was interesting that after 3 h of cooking in boiling water, the plywoods specimens bonded with lignin-based phenolic adhesives displayed higher bonding strength than the corresponding dry strength obtained after direct conditioning at 20 °C and 65% RH. Compared with NPF, lignin introduction significantly reduced the bonding strength of lignin based phenolic adhesives when applied for plywood lamination. However, no significant variation of bonding strength was detected among the lignin based phenolic adhesives, regardless of lignin methylolation or adding stages.Xianbin AiShanghuan FengTao ShuiHimant KakkarChunbao Charles XuMDPI AGarticleAlcell ligninlignin methylolationphenolic adhesiveslignin based phenolic adhesivesOrganic chemistryQD241-441ENMolecules, Vol 26, Iss 6762, p 6762 (2021)
institution DOAJ
collection DOAJ
language EN
topic Alcell lignin
lignin methylolation
phenolic adhesives
lignin based phenolic adhesives
Organic chemistry
QD241-441
spellingShingle Alcell lignin
lignin methylolation
phenolic adhesives
lignin based phenolic adhesives
Organic chemistry
QD241-441
Xianbin Ai
Shanghuan Feng
Tao Shui
Himant Kakkar
Chunbao Charles Xu
Effects of Alcell Lignin Methylolation and Lignin Adding Stage on Lignin-Based Phenolic Adhesives
description To investigate the effects of lignin methylolation and lignin adding stage on the resulted lignin-based phenolic adhesives, Alcell lignin activated with NaOH (AL) or methylolation (ML) was integrated into the phenolic adhesives system by replacing phenol at various adhesive synthesis stages or directly co-polymerizing with phenolic adhesives. Lignin integration into phenolic adhesives greatly increased the viscosity of the resultant adhesives, regardless of lignin methylolation or adding stage. ML introduction at the second stage of adhesive synthesis led to much bigger viscosity than ML or AL introduction into phenolic adhesives at any other stages. Lignin methylolation and lignin adding stage did not affect the thermal stability of lignin based phenolic adhesives, even though lignin-based adhesives were less thermally stable than NPF. Typical three-stage degradation characteristics were also observed on all the lignin-based phenolic adhesives. Three-ply plywoods can be successfully laminated with lignin based adhesives, and it was interesting that after 3 h of cooking in boiling water, the plywoods specimens bonded with lignin-based phenolic adhesives displayed higher bonding strength than the corresponding dry strength obtained after direct conditioning at 20 °C and 65% RH. Compared with NPF, lignin introduction significantly reduced the bonding strength of lignin based phenolic adhesives when applied for plywood lamination. However, no significant variation of bonding strength was detected among the lignin based phenolic adhesives, regardless of lignin methylolation or adding stages.
format article
author Xianbin Ai
Shanghuan Feng
Tao Shui
Himant Kakkar
Chunbao Charles Xu
author_facet Xianbin Ai
Shanghuan Feng
Tao Shui
Himant Kakkar
Chunbao Charles Xu
author_sort Xianbin Ai
title Effects of Alcell Lignin Methylolation and Lignin Adding Stage on Lignin-Based Phenolic Adhesives
title_short Effects of Alcell Lignin Methylolation and Lignin Adding Stage on Lignin-Based Phenolic Adhesives
title_full Effects of Alcell Lignin Methylolation and Lignin Adding Stage on Lignin-Based Phenolic Adhesives
title_fullStr Effects of Alcell Lignin Methylolation and Lignin Adding Stage on Lignin-Based Phenolic Adhesives
title_full_unstemmed Effects of Alcell Lignin Methylolation and Lignin Adding Stage on Lignin-Based Phenolic Adhesives
title_sort effects of alcell lignin methylolation and lignin adding stage on lignin-based phenolic adhesives
publisher MDPI AG
publishDate 2021
url https://doaj.org/article/995da34084e442c0a9cfc2b823135447
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AT taoshui effectsofalcellligninmethylolationandligninaddingstageonligninbasedphenolicadhesives
AT himantkakkar effectsofalcellligninmethylolationandligninaddingstageonligninbasedphenolicadhesives
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