Controlled functionalization of sp2 carbon allotropes for the reinforcement of diene elastomers

摘要

To achieve important mechanical properties, natural and synthetic rubbersudneed reinforcing fillers. sp2 carbon allotropes are indeed relevant reinforcing fillers forudrubber compounds. Carbon black has been used for over a century and nanofillersudsuch as graphene, graphene related materials and carbon nanotubes are dramaticallyudincreasing their importance. Ultimate distribution and dispersion of the carbon fillers inudthe rubber compounds has to be obtained. To achieve this goal, carbon allotropesudshould be used as such or should they be functionalized?udIn this work, controlled functionalization of sp2 carbon allotropes wasudperformed. In particular, the aim was to introduce, on carbon allotropes, oxygenatedudfunctional groups, without altering the graphitic structure of the substrate. Methodsuddeveloped are presented. They were based on reaction of carbon materials withudhydrogen peroxide, potassium hydroxide and a derivative of 2-amino-1,3-udpropandiol, better known as serinol. All the reactions were inspired to the basicudprinciple of sustainable chemistry, with the aim to avoid the use of solvents andudcatalysts. Research performed with the serinol derivative is in particular discussed. TheudPaal-Knorr reaction of serinol with 2,5-hexanedione was performed, obtaining 2-ud(2,5-dimethyl-1H-pyrrol-1-yl)-1,3-propanediol, named as serinolpyrrole (SP). Theudaromatic ring in SP was exploited to form stable adducts with the carbon allotropes.udHypothesis on the mechanism for the adduct formation is presented.udRubber compounds, based either only on carbon black or on carbon black andudsilica as the filler systems, were prepared and sulphur-based crosslinking behavior anduddynamic-mechanical properties were investigated.