High performance benzoxazine/CNT nanohybrid network – An easy and scalable way to combine attractive properties

•Robust synthesis of a thermostable diamine based benzoxazine.•Excellent interaction of carbon nanotubes with benzoxazine precursor.•Nanohybrid formation with high thermomechanical, electrical and fire properties.•Correlation between electrical percolation and internal scaffold formation.•Shape and volume integrity during pyrolysis upon 1000 °C.

This work presents a scalable and solventless synthesis of a diamine based benzoxazine and the subsequent preparation of nanocomposites with pristine multiwalled carbon nanotubes (CNTs). The synthesized precursor showed an improved thermal stability upon curing temperature pushing aside the main drawback of benzoxazine resins. It exhibits excellent intrinsic properties and strong natural interactions with CNTs. The increase of thermomechanical stability was found to be dependent on the filler content with an optimum at 0.5 wt.% of CNTs. An electrical percolating network was established with low CNT content, around 0.3 wt.%. The volumic variation due to thermal degradation at high temperature was severely restricted in the presence of CNTs and was correlated to the formation of a percolating network acting as an internal reinforcing framework. The limiting oxygen indexes of nanocomposites were found to be remarkably high, above 38%, showing the potential to fabricate novel promising high performance materials. The resulting attractive properties were attributed to the strong interactions between CNTs and polybenzoxazine.

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