Abstract
In this study, the development of lignin-based resins for wood adhesion applications was demonstrated. We investigated two lignin fractions: commercial Protobind 1000 lignin and methanol-soluble Protobind 1000 lignin fraction after mild solvolysis. Although lignin has previously been incorporated into various cross-linked systems, this is the first report on lignin-based thermosets obtained via thiol-yne "click" chemistry. In this approach, lignin was functionalized with terminal alkyne groups followed by cross-linking with a multifunctional thiol, resulting in polymeric network formation. The influence of the curing conditions on the resin characteristics and performance was studied, by varying the amount of reactive monomeric diluents. Additionally, a post-curing strategy utilizing the Claisen rearrangement was investigated. These resins were tested as a wood adhesive and were proven to possess a desirable performance, comparable to the state-of-art phenol-formaldehyde resins. Lignin-based thiol-yne resins turn out to be an alternative to phenol-formaldehyde resins, currently used as adhesives and coatings. Although it is possible to use lignin in phenol-formaldehyde resins, lignin addition is compromising the resin's performance. The main benefits over the phenol-formaldehyde approach are that higher lignin loadings are possible to achieve, and no volatiles are emitted during the resin processing and use.
Original language | English |
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Pages (from-to) | 2544-2552 |
Number of pages | 9 |
Journal | ACS Applied Polymer Materials |
Volume | 4 |
Issue number | 4 |
DOIs | |
Publication status | Published - 8 Apr 2022 |
Keywords
- lignin
- propargylated lignin
- thiol-yne
- "click" chemistry
- thermosets
- wood adhesives
- TECHNICAL LIGNINS
- DEPOLYMERIZATION
- FRACTIONATION
- CHEMISTRY