Design, synthesis and Chemical-physical characterization of photocatalytic inorganic nanocrystals for technological applications

This work was based on the synthesis and characterization of innovative crystals for biomedical and technological applications. Different types of syntheses were developed in order to obtain crystals with high photocatalytic properties. A hydrothermal synthesis was also processed to correlate the chemical-physical characteristics with synthesis parameters obtaining synthesis of nanoparticles of titanium dioxide with different morphology, size and crystalline phase depending on the variation of the synthesis parameters. Also a synthesis in water at 80 °C temperature and low pressure was developed from which anatase containing a small percentage of brookite nanoparticles were obtained, presenting a high photocatalytic activity. These particles have been used to obtain the microcrystals formed by an inorganic core of hydroxyapatite surface covered by TiO2 nanoparticles. Micrometer material with higher photocatalytic has been produced. The same nanoparticles have been functionalized with resorcinol oxidized in order to increase the photocatalytic efficiency. Photodegradation test results have confirmed this increase. Finally, synthetic nanoparticles with a waterless synthesis using formic acid and octanol, through esterification "in situ" were synthesized. Nanoparticles superficially covered by carboxylic residues able to bind a wide range of molecules to obtain further photocatalytic properties were obtained.

Fully bio-based epoxy resins

Epoxy resins are mainly produced by reacting bisphenol A with epichlorohydrin. Growing concerns about the negative health effects of bisphenol A are urging researchers to find alternatives. In this work diphenolic acid is suggested, as it derives from levulinic acid, obtained from renewable resources. Nevertheless, it is also synthesized from phenol, from fossil resources, which, in the current paper has been substituted by plant-based phenols. Two interesting derivatives were identified: diphenolic acid from catechol and from resorcinol. Epichlorohydrin on the other hand, is highly carcinogenic and volatile, leading to a tremendous risk of exposure. Thus, two approaches have been investigated and compared with epichlorohydrin. The resulting resins have been characterized to find an appropriate application, as epoxy are commonly used for a wide range of products, ranging from composite materials for boats to films for food cans. Self-curing capacity was observed for the resin deriving from diphenolic acid from catechol. The glycidyl ether of the diphenolic acid from resorcinol, a fully renewable compound, was cured in isothermal and non-isothermal tests tracked by DSC. Two aliphatic amines were used, namely 1,4-butanediamine and 1,6-hexamethylendiamine, in order to determine the effect of chain length on the curing of an epoxy-amine system and determine the kinetic parameters. The latter are crucial to plan any industrial application. Both diamines demonstrated superior properties compared to traditional bisphenol A-amine systems.