To develop siloxane-containing vitrimers with fast dynamic characteristics, different mechanistic pathways have been investigated using a range of catalysts. In particular, one siloxane exchange pathway has been found to show a fast dynamic behavior in a useful temperature range (180−220 °C) for its application in vitrimers. The mechanism is found to involve 1,5,7-triazabicyclo [4.4.0] dec-5-ene (TBD) as an organic catalyst in the presence of hydroxyl groups. Using this new mechanistic approach, vitrimers with ultrafast stress-relaxation characteristics (relaxation times below 10 s) have been prepared with a readily available epoxy resin and siloxane-amine hardener. Subsequently, the low viscosity siloxane-containing vitrimer resin enabled the preparation of glass fiber-reinforced vitrimer composites using an industrially relevant vacuum-assisted resin infusion technique. The resulting composite was successfully thermoformed into a new shape, which makes it possible to envision a second life for such highly engineered materials.

Research on bio-based covalent adaptable networks is popular nowadays in the search for an optimal implementation of thermoset materials and composites in a circular context. Herein, a vanillin derivative is...

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As part of our ongoing study investigating isohexide-based polyamides, we have synthesized isosorbide(bis(propan-1-amine)) (DAPIS) and studied its reactivity in the polymerization towards fully biobased polyamides.

A facile strategy to obtain nacre-mimetic nanocomposite materials is presented. The proposed economically feasible and environmentally friendly process consists in fusing dynamic poly(lipoic acid) and montmorillonite (MTM) via a water evaporation method. Lipoic acid (LA), a naturally occurring molecule, can readily undergo thermal-, UV-, or (water) evaporation-induced dynamic ring-opening polymerization. This monomer has been equipped with various organic and inorganic counter cations, altering the physical properties of both the obtained poly(lipoate)s and the resulting nacre-like nanocomposites. The mechanical performance of the nanocomposites can be accordingly tuned from rigid and brittle to soft and ductile. Importantly, the composites containing triethanolammonium cations show enhanced ductility with an elongation at break up to around 16% when compared to other reported nacre-mimetic nanocomposites with similar MTM content (elongation at break usually below 10%). Moreover, the influence of MTM content on the mechanical properties of the nanocomposites is elucidated. Furthermore, the dynamic nature of the poly(lipoate)s and supramolecular architecture within the composites enables water-assisted self-healing of superficial scratches, as evaluated by optical microscopy, and closed-loop recycling for materials with up to 70 wt % MTM. Finally, the nanocomposites were found to exhibit flame retardancy.