Bio-based high performance thermosets: Stabilization and reinforcement of eugenol-based benzoxazine networks with BMI and CNT

•Robust synthesis of a bio based bis-benzoxazine.•Copolymerization with a bismaleimide.•Adjustment of crosslinking density with the comonomère content.•Excellent interaction of carbon nanotubes with benzoxazine precursor.•Nanohybrid formation with excellent thermomechanical properties.

This work presents the solventless synthesis, the reinforcement and the thermal stabilization of bio-based bis-benzoxazine resins derived from eugenol. The structure of this benzoxazine monomer was confirmed by 1H NMR. The polymerization and degradation of the precursor have been investigated and monitored by DSC and TGA and showed a limited crosslinking ability due to the steric hindrance of the eugenol based aromatic ring. A bis-maleimide (bMI) has been used to stabilize the benzoxazine moiety while it undergoes also a copolymerization through an ene-addition. Depending on its relative content, the bis-maleimide proved to limit the thermal degradation of the bis-benzoxazine monomer and allowed the formation of a dense crosslinked network with high thermomechanical stability. Furthermore, the properties of the network were significantly improved by the incorporation of a small amount of carbon nanotubes (CNTs) with an increase of the Tg as high as 60 °C. The combination of bMI and CNTs will allow the use of this new bio-based benzoxazine resin as matrices for the preparation of sustainable high performance biocomposite materials.

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