Antioxidants, particularly those designed for use in hydrocarbon media, suffer from a variety of limitations including high volatility and poor solubility. Using 2,2bis(hydroxymethyl)propionic acid as the branching unit, a series of novel dendrons featuring 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic ester chain ends have been synthesised to provide improved solubility of such hindered phenolic antioxidants. The thermal stability, assessed by thermogravimetric analysis, revealed that all the functionalised dendrons have enhanced thermal stability when compared to commercial antioxidants (BHT, Irganox L135 and Irganox L57). Antioxidant ability was evaluated using pressurised differential scanning calorimetry and when blended with a lubricant base oil, at 0.5% w/w, an increase in antioxidant performance was observed when compared to the commercial antioxidants.

In this study, a series of core units (glycerol, triethanolamine and triisopropanolamine derivatives) were investigated for their use in tri-armed phenolic antioxidants. The antioxidant ability of these tri-armed phenolic compounds featuring different core units were then evaluated in a hydrocarbon lubricant using differential scanning calorimetry (DSC) and compared to the commercially available antioxidants Irganox L135 and Irganox L57. An impressive oxidation induction time of ca. 9-12 minutes was observed for the glycerol based antioxidants when compared to the commercial antioxidants (ca. 4-6 minutes), whereas in contrast in the case of triethanolamine and triisopropanolamine derived antioxidants, a solubilising unit was incorporated in order to provide appropriate solubility within the hydrocarbon medium and revealed an excellent oxidation induction time of ca. 11-12 minutes.

Increasing the antioxidant capability via the synergistic effect of coupling diphenylamine with sterically hindered phenol. Tetrahedron, 75 (51). 130759.

By taking inspiration from the food industry, an assay was investigated as a potential screening tool to test the efficiency of new phenolic antioxidants. The method was based on the spectrophotometric measurement of the stable free radical 1,1diphenyl-2-picryl hydrazyl (DPPH) which, in its radical form, has an absorbance maxima at 515 nm. The disappearance of this absorbance band, upon reaction with an antioxidant, was monitored to reveal the kinetic pathway of the reaction, which was defined simply as either fast, medium or slow. Adaptation of the assay was attempted for application to biofuels and oilbased automotive fluids whereby the effect of polar and nonpolar solvents on the kinetics of the reaction was investigated. In addition, the stoichiometry of the radical scavenging reaction was also analysed to give an insight into the structureactivity relationships of phenolic antioxidants.

A novel series of low molecular weight non-peptidic, biocompatible super-hydrogelators with both water purification and drug delivery properties have been developed. Linking the bis aromatic urea groups responsible for gelation together to form biand tri-armed gelators, affords good control over gelation and water purification properties. The use of the gels as effective drug scavengers and delivery systems has been demonstrated with dye substrates, via pH inversion, as monitored by UV-vis spectroscopy. Finally, the systems' abilities as both drug scavenging and delivery systems have been demonstrated with the clinically-approved drugs chlorpromazine and doxorubicin, respectively.