A recently reported functionalization of single and multi-walled carbon nanotubes, based on a cycloaddition reaction between carbon nanotubes and a pyrrole derived compound, was exploited for the formation of a doxorubicin (DOX) stacked drug delivery system. The obtained supramolecular nano-conveyors were characterized by wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (TGA), high-resolution transmission electron microscopy (HR-TEM), and Fourier transform infrared (FT-IR) spectroscopy. The supramolecular interactions were studied by molecular dynamics simulations and by monitoring the emission and the absorption spectra of DOX. Biological studies revealed that two of the synthesized nano-vectors are effectively able to get the drug into the studied cell lines and also to enhance the cell mortality of DOX at a much lower effective dose. This work reports the facile functionalization of carbon nanotubes exploiting the “pyrrole methodology” for the development of novel technological carbon-based drug delivery systems.

High-yield regioselective synthesis of imines and oxazolidines derivatives of 2-amino-1,3-propandiol (serinol) was achieved by performing the reaction with aldehydes and ketones, in the absence of solvents and catalysts. Only imines were obtained when the carbonyl compound was aromatic and/or sterically hindered and when conjugated double bonds were formed. 1,3-Oxazolidines were specifically obtained with either aldehydes or ketones with limited steric hindrance. The "green" reaction conditions here adopted for the synthesis of these classes of derivatives are not due to the structural and functional peculiarity of the serinol as a reactant and can also be extended to lipophilic amines with the same good results in terms of yield and selectivity. A revision of the mechanism typically accepted in the presence of solvent and catalysis is proposed, and the quantum mechanics calculations applied to some derivatives are in good agreement with the proposed rationalizations of the selectivity observed. Serinol itself and the imine and oxazolidine derivatives were used, in place of guanidine, as accelerators in compounds based on diene rubbers and silica, suitable for application in tire treads with low environmental impact. Efficient sulfur-based cross-linking and composites with a low dissipation of energy were obtained. The oxazolidine and imine appear to act as protective groups of the serinol primary amine. This work paves the way for the selective synthesis of biosourced families of chemicals, which could be used for large-scale applications, such as the one in rubber compounds, replacing toxic oil-based chemicals.

A biosourced Janus molecule was used as a coupling agent between silica and unsaturated polymer chains in an elastomeric composite suitable for tire compounds with low energy dissipation, with potential important reduction of the environmental impact of the tire. 2-(2,5-Dimethyl-1H-pyrrol-1-yl)-1,3-propanediol (serinol pyrrole, SP) was synthesized through the neat reaction of serinol and 2,5-hexanedione, with a high atom efficiency (ca. 85%). Adducts of SP with silica were prepared (SP ≈ 9% by mass), with very high yield. In the whole process, from reagents to adducts, only substances from natural sources could be used, and the only co-product was water and the carbon efficiency was close to 100%. The silica/SP adduct was used in an elastomeric composite based on diene elastomers such as poly(styrene-cobutadiene) and poly(1,4-cis-isoprene) from Hevea brasiliensis. Comparison was made with a composite containing silica and a traditional coupling agent, a sulfur-based silane, bis(triethoxysilylpropyl)tetrasulfide (TESPT). SP appears to behave as a coupling agent for silica. To have similar properties for the SP and TESPT-based composites, tuning of the formulation of the composite with silica/SP has to be performed. Model reactions revealed the condensation of the OH of SP with the SiOR groups of an alkoxysilane, the reaction of the pyrrole ring with sulfur and a thiyl radical and the reaction of the sulfurated pyrrole ring with the unsaturation of squalene. SP appears thus able to establish covalent bonds with both silica and the unsaturated elastomer. With SP, the release of ethanol, which occurs from the silanization of silica with TESPT and is usually burned in industrial plants to give CO 2 , is avoided. This work paves the way for the development at the industrial scale of elastomeric composites which allow remarkable reduction of the carbon footprint of the tire technology.

Polyurethane nanocomposites were prepared with a nanosized high surface area graphite (HSAG) functionalized on its edges with hydroxyl groups as a building block. Edge functionalization of HSAG was obtained through reaction with KOH. The addition of OH groups was demonstrated by means of infrared (FTIR) and thermogravimetric analysis (TGA), and the Boehm titration allowed estimation of a level of about 5.0 mmolOH/gHSAG. Results from wide-angle X-ray diffraction (WAXD) and Raman spectroscopy suggested that functionalization of the graphene layers occurred on the edges. The evaluation of the Hansen solubility parameters of G-OH revealed a substantial increase of δPand δH parameters with respect to HSAG. In line with these findings, homogeneous and stable dispersions of G-OH in a polyol were obtained. PU were prepared by mixing a dispersion of G-OH in cis-1,4-butenediol with hexamethylene diisocyanate. A model reaction between catechol, 1,4-butanediol, and hexamethylene diisocyanate demonstrated the reactivity of hydroxylated aromatic rings with isocyanate groups. PU-based G-OH, characterized with WAXD and differential scanning calorimetry (DSC), revealed lower Tg, higher Tc, Tm, and crystallinity than PU without G-OH. These results could be due to the higher flexibility of the polymer chains, likely a consequence of the dilution of the urethane bonds by the carbon substrate. Hence, G-OH allowed the preparation of PU with a larger temperature range between Tg and Tm, with potential positive impact on material applications. The model reaction between butylisocyanate and 1-butanol revealed that HSAG and G-OH promote efficient formation of the urethane bond, even in the absence of a catalyst. The effect of high surface area carbon on the nucleophilic oxygen attack to the isocyanate group can be hypothesized. The results here reported lead us to comment that a reactive nanosized sp2 carbon allotrope, such as G-OH, can be used as a multifunctional building block of PU. Indeed, G-OH is a comonomer of PU, a promoter of the polymerization reaction, and can definitely act as reinforcing filler by tuning its amount in the final nanocomposite leading to highly versatile materials. The larger temperature range between Tg and Tm, together with the presence of G-OH acting as a reinforcing agent, could allow the production of piezoresistive sensing, shape-memory PU with good mechanical features.

Inspired by decades of research in the compatibilization of fillers into elastomeric composites for high‐performance materials, a novel polyurethane‐based stretchable carbon ink is created by taking advantage of a Janus molecule, 2‐(2,5‐dimethyl‐1H‐pyrrol‐1‐yl)propane‐1,3‐diol (serinol pyrrole, SP). SP is used to functionalize the carbon and comonomer in the polymer phase. The use of SPs in both the organic and inorganic phases results in an improved interaction between the two phases. When printed, the functionalized material has a factor 1.5 lower resistance‐strain dependence when compared to its unfunctionalized analogue. This behavior is superior to commercially available carbon inks. To demonstrate the suitability of ink in an industrial application, an all‐printed, elastomer‐based force sensor is fabricated. This “pyrrole methodology” is scalable and broadly applicable, laying the foundation for the realization of printed functionalities with improved electromechanical performance.