# New recyclable elastomers: On the benefit on using maleimide functional oligolignin as reversible biosourced crosslinking agents

Rémy Devienne, Karim Delage, Marion Eternot, Romain Tavernier, Sandra Tapin-Lingua, Véronique Bounor-Legare, L. Djakovitch

<figure><img src="image_1.png" /></figure>

## ► To cite this version:

Rémy Devienne, Karim Delage, Marion Eternot, Romain Tavernier, Sandra Tapin-Lingua, et al. New recyclable elastomers: On the benefit on using maleimide functional oligolignin as reversible biosourced crosslinking agents. International Symposium on Green Chemistry - ISGC 2025, May 2025, La Rochelle, France. hal-05127475

HAL Id: hal-05127475

https://hal.science/hal-05127475v1

Submitted on 24 Jun 2025

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_2.png" /></figure>
# New recyclable elastomers: On the benefit on using maleimide functional oligolignin as reversible biosourced crosslinking agents.

Rémy DEVIENNE b(a,b), Karim DELAGE(a), Marion ETERNOT(b), Romain TAVERNIER(a), Sandra TAPIN-LINGUA(c), Véronique BOUNOR-LEGARE (a), Laurent DJAKOVITCH (b)

(a) Universite Claude Bernard Lyon 1, INSA Lyon, Université Jean Monnet, CNRS UMR 5223, Ingénierie des Matériaux Polymères F-69622, Villeurbanne cédex, France

(b) Institut de Recherches sur la Catalyse et l'Environnement de Lyon, UMR 5256 – CNRS / Université Lyon 1 – Villeurbanne Cedex, France

(c) FCBA – Grenoble / Domaine Universitaire – CS 90251 / 38044 Grenoble Cedex 9

With increasing environmental concerns over conventional polymers, there is an urgent need for sustainable alternatives. The recyclability and the longevity of plastic materials are important levers for the sustainability of polymers industry, particularly for the crosslinked elastomers. In the same time, on the last years, the interest for the lignin valorisation have grown exponentially. Actually, lignin can bring relevant properties for materials such as antioxidant and UV resistance. Hence, lignin and elastomers have been associated to bring mechanical reinforcement concomitantly to crosslinking action but without specific control of the size and functionality of the lignin.[1-2] Thus to bring news knowledges in this field, we first studied partial depolymerisation of lignins in acidic media[3] to obtain oligolignins with controlled molar mass and size. The impact on the dispersion of the oligolignins in a natural elastomer and its reactivity were compared the results obtained with the non-depolymerized lignins and with a lignin model synthesized called Beta C. Crosslinking reactions were performed in bulk without solvent in an internal mixer at 200°C for 12 min. After cooling down, the crosslinking density was evaluated by the determination of the insoluble fraction, using a Soxhlet apparatus with THF for 48h. The preliminary results suggest that high molar masses lignins lead to lower crosslinking densities and high soluble fraction, indicating ineffective crosslinking ability.

<figure><img src="image_3.png" /><figcaption>Fig 1: The used internal mixer « haake »</figcaption></figure>

This approach based on the synthesis of the Beta C model allowed also to screen different functionalization (Qualified and quantified by NMR spectroscopy). After successful obtention of functionalized models, the optimal conditions were selected to functionalize the oligolignins and lignins. Different chemistries were evaluated, such as thiol functionalization (envisioning thiol-ene crosslinking strategy). We were also interested by the possibility to implement Diels-Alder reversible crosslinking strategy. In that frame, amines were chosen for their high reactivity, versatility and the possibility to further obtain a maleimide residue. Amine functionalisation was inspired from recently published work.[4]
These conditions lead first to the addition of acetyl-protected amines, which are then unprotected. The control of this deprotection strategy allowed us to control the functional density on lignins. Maleimide is finally obtained quantitatively using maleic anhydride with a solution of the aminolignin. In the other hand, epoxidized natural rubber (ENR) was grafted with furan moiety, using biobased furfurylamine in a few hours.[5]

<figure><img src="image_4.png" /><figcaption>Figure 2: Synthesis of the maleimide and furan moieties and their use in DA reaction</figcaption></figure>

The Diels-Alder and retro Diels-Alder reactions were evaluated through similar methodology as the one described previously: reactive blending in an internal mixer and evaluation of the crosslinking density. A focus had been done on the reversibility of this system.

These results are encouraging and provide a first proof of concept of our synthesis strategy in order to obtain fully reversible networks. Thus polymers having self-healing properties are looked forward. Diels-Alder reaction is a useful reversible reaction that can bring such self-healing properties from furan and maleimide moieties

Reference:

[1] P. Alexy, B. Kosikova, G. Podstranska, *Polymer* (Elsevier science) **2000**, *41*, 4901-4908.

[2] H. Wang, W. Liu, J. Huang, D. Yang, X. Qiu, *Polymers* (Basel) **2018**, *10*, 1033-1047.

[3] K. L. R. Lundgren, *Acta chemica scandinavica* **1972**, *26*, 2005-2023.

[4] A. D. Nathan Wybo, and Luc Averous, *Angewandte Chemie* **2024**, e202403806, 1-15.

[5] S. K. Raut, P. Mondal, B. Parameswaran, S. Sarkar, P. Dey, R. Gilbert, S. Bhadra, K. Naskar, S. Nair, N. K. Singha, *European Polymer Journal* **2021**, 146.