Ludovic Dumas

Eugenol-based benzoxazine: from straight synthesis to taming of the network properties

Mixed benzoxazine precursors were synthesized using a blend of eugenol, a natural renewable product, and phenol. The structures of these mixed benzoxazine precursors with different phenol:eugenol compositions were attested by 1H NMR. Their polymerization and degradation were investigated and monitored by DSC and TGA and showed an enhancement of the crosslinking ability with the phenol content. Depending on its relative content, the phenol moiety proved to limit the thermal degradation of the bis-benzoxazine “hybrid” monomer and allowed the formation of crosslinked networks with high thermomechanical stabilities. The properties of the networks were closely dependent on the phenol:eugenol ratio, which allowed for adjustment of the crosslinking density and fine tuning of the glass transition temperature (Tg) within a wide temperature range. A comparison between the polymerized hybrid precursors and blend of two pure monomers displaying the same overall composition showed the same material properties increasing the tunability of the system. The eugenol/phenol combination for the preparation of mixed/hybrid benzoxazines or corresponding blends clearly paves the way to new sustainable high performance bio-based materials.

Arbutin-based benzoxazine : en route to an intrinsic water soluble biobased resin

A novel benzoxazine monomer containing a carbohydrate moiety was synthesized using a solventless approach from the reaction of arbutin, a naturally occurring phenolic compound, furfurylamine and formaldehyde. The chemical structure of this fully bio-based benzoxazine monomer was confirmed by 1H NMR and FTIR. Its polymerization has been investigated and monitored by DSC showing the ring opening polymerization of benzoxazine functions with a network densification thanks to the reaction of the furan group. The high hydroxyl content of the monomer allows its easy solubilisation in water paving the way to a wide range of possible “environmentally friendly” applications especially in the fields of coatings, paintings and adhesives.

Polybenzoxazine Nanocomposites : Case Study of Carbon Nanotubes

Due to their excellent mechanical, electrical, and thermal properties, carbon nanotubes (CNTs) are considered as the nanofillers of choice to reinforce organic-based materials and to provide additional specific properties that allow a number of exciting potential applications in the energy, electronic, biotechnology, and nanotechnology areas. This chapter presents a review of the most recent progress on the development of polybenzoxazine/CNT-based composites. More specifically, the role of the different CNT functionalization, process dispersion, and benzoxazine-CNT interactions on the resulting material properties are discussed and the key-factors leading to an effective nanoreinforcement of the benzoxazine matrix without losing the physical properties of CNTs are highlighted. This chapter aims to demonstrate the great potential of the benzoxazine/CNT couple, which can lead to unique properties.

Do Carbon Nanotubes Improve the Thermomechanical Properties of Benzoxazine Thermosets

Fillers are widely used to improve the thermomechanical response of polymer matrices, yet often in an unpredictable manner because the relationships between the mechanical properties of the composite material and the primary (chemical) structure of its molecular components have remained elusive so far. Here, we report on a combined theoretical and experimental study of the structural and thermomechanical properties of carbon nanotube (CNT)-reinforced polybenzoxazine resins, as prepared from two monomers that only differ by the presence of two ethyl side groups. Remarkably, while addition of CNT is found to have no impact on the glass-transition temperature ( Tg) of the ethyl-decorated resin, the corresponding ethyl-free composite features a surge by ∼47 °C (50 °C) in Tg, from molecular dynamics simulations (dynamic mechanical analysis measurements), as compared to the neat resin. Through a detailed theoretical analysis, we propose a microscopic picture for the differences in the thermomechanical properties of the resins, which sheds light on the relative importance of network topology, cross-link and hydrogen-bond density, chain mobility, and free volume.

Novel porous nanohybrid materials with unexpected mechanical and electrical performance by pyrolysis of carbon nanotube-filled benzoxazine thermosets

Abstract In this communication, we highlight the remarkable and unexpected mechanical and electrical properties of new porous nanohybrid materials as readily obtained by a two-step preparation procedure. Neat multi-wall carbon nanotube (CNT)-reinforced benzoxazine nanocomposites were first produced. At a CNT content of 5 wt%, pyrolysis of the nanocomposites allowed for recovering porous monolithic nanohybrid materials exhibiting outstanding mechanical resistance (elastic modulus of ca. 50 MPa) for an electrical conductivity as high as 30 S cm−1. Interestingly, long CNTs were found to build up an internal scaffold limiting the deformation of the foamed structure and preserving the geometric shape and dimensional integrity of the sample along the pyrolysis process. The concept of this novel approach paves the way for the production of a very promising choice of viable (nano)materials for use as domains as versatile as in energy storage, catalysis, or shielding applications.