High-value utilization of hydroxymethylated lignin in polyurethane adhesives

Copyright © 2020 Elsevier B.V. All rights reserved..

Lignin is a good candidate for the polymerization and chemical modification to prepare sustainable chemicals and materials, but a relatively low hydroxyl content becomes an obstacle for the preparation of lignin-based polyurethane (PU) adhesives. In order to improve its reactivity, the acetic acid lignin (AAL) was hydroxymethylated before copolymerized with isocyanate during the preparation of PU adhesives. The hydroxymethylation was carried out in an alkaline formaldehyde solution and it was found that 85 °C is the optimal temperature. On that condition, the free formaldehyde content of the corresponding product HL-6 was as low as 0.32%, while the hydroxymethyl was increased by 189.11% compared with original AAL and reached 2.92 mmol/g. In the polymerization of PU adhesives, the hydroxymethylated lignin with a higher aliphatic hydroxyl content formed a more compact three-dimensional urethane cross-linking network with isocyanate. The mechanical properties and thermal stability of the lignin-based PU adhesive were improved by 15-30 wt% in HL-6, and particularly the tensile strength was increased by 21-41 MPa, which indicated that the hydroxymethylation is an efficient way to enrich the hydroxyl in lignin, and the modified lignin is adequate to partially replace petroleum-based polyols for the preparation of PU adhesives with excellent properties.

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:152

Enthalten in:

International journal of biological macromolecules - 152(2020) vom: 01. Juni, Seite 775-785

Sprache:

Englisch

Beteiligte Personen:

Chen, Yinchen [VerfasserIn]
Zhang, Hui [VerfasserIn]
Zhu, Zhaodong [VerfasserIn]
Fu, Shiyu [VerfasserIn]

Links:

Volltext

Themen:

1HG84L3525
9005-53-2
Acetic Acid
Acetic acid lignin
Adhesives
Formaldehyde
Hydroxymethylation
Isocyanates
Journal Article
Lignin
Petroleum
Polymers
Polyol
Polyurethane adhesive
Polyurethanes
Q40Q9N063P

Anmerkungen:

Date Completed 03.02.2021

Date Revised 03.02.2021

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1016/j.ijbiomac.2020.02.321

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM307117480