Chemical interactions between aqueous vanadium species and aluminium alloy AA6063-T5 were investigated in vanadate-containing NaCl solutions. Confocal Raman and X-ray photoelectron spectroscopy experiments were utilised to gain insight into the mechanism of corrosion inhibition by vanadates. A greenish-grey coloured surface layer, consisting of V+4 and V+5 polymerized species, was seen to form on the alloy surface, especially on top of cathodic micrometre-sized IMPs, whereby suppressing oxygen reduction kinetics. The results suggest a two-step mechanism of corrosion inhibition in which V+5 species are first reduced to V+4 or V+3 species above cathodic IMPs, and then oxidized to mixed-valence V+5/V+4 polymerized compounds.

Corrosion inhibition of aluminum alloy AA6063-T5 by vanadates (NaVO3) in 0.05 M NaCl solution has been investigated by electrochemical and weight loss measurements, and associated with microstructure and Volta potential data. X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy analyses confirmed the presence of micrometer-sized Fe-rich Al4.01MnSi0.74, Al1.69Mg4Zn2.31, and FeAl3 intermetallic phases (IMPs) and nanometer-sized CuAl2, ZnAl2, and Mg2Si precipitates in the microstructure. Scanning Kelvin probe force microscopy measurements showed Volta potential differences of up to 600 mV between the microstructure constituents indicating a high susceptibility to micro-galvanic corrosion, with interphase boundary regions exhibiting the highest propensity to corrosion. Most IMPs had cathodic character whereas some nanometer-sized Mg-rich particles exhibited anodic nature, with large Volta potential gradients within interphase regions of large cathodic particles. Electrochemical potentiodynamic polarization measurements indicated that the vanadates provided mixed corrosion inhibition effects, mitigating both oxygen reduction, occurring on cathodic IMPs, and anodic metal dissolution reaction, occurring on anodic sites, such as Mg2Si and interphase boundary regions. Electrochemical measurements indicated that the sodium metavanadate inhibitor blocks active metal dissolution, giving high inhibition efficiency (>95%) during the initial exposure, whereas long-term weight loss measurements showed that the efficacy decreases after prolonged exposure.

Cu(0) mediated living radical polymerization was successfully applied to synthesize graft-copolymers from the hemicellulose acetylated galactoglucomannan. Functionalizing the polysaccharide backbone with α-bromo isobutyric acid gave rise to a macroinitiator for single-electron-transfer mediated living radical polymerization (SET-LRP). This macroinitiator with a degree of substitution of 0.15 or 0.20 was used in the graft-SET-LRP of methyl methacrylate in dimethyl sulfoxide as well as N-isopropyl acrylamide and acrylamide in water. Kinetic analyses confirm conversions of up to 73% and a controlled behavior of the SET-LRP process providing high molecular weight hemicellulose-based hybrid copolymers with a brush-like architecture. Derived graft-copolymers varied significantly in solubility properties, ranging from hydrophobic via temperature responsive water-solubility to water-soluble.

A multifunctional macroinitiator for single-electron-transfer mediated living radical polymerization (SET-LRP) was designed from acetylated galactoglucomannan (AcGGM) by alpha-bromoisobutyric acid functionalization of the anomeric hydroxyl groups on the heteropolysaccharide backbone. This macroinitiator, with a degree of substitution of 0.15, was used in the SET-LRP of methyl acrylate, catalyzed by Cu-0/Me-6-TREN in DMSO, DMF, or DMSO/H2O in various, concentrations. Kinetic analyses confirm high conversions of up to 99.98% and a living behavior of the SET-LRP process providing high molecular weight hemicelluloses/methyl acrylate hybrid copolymers with a brush-like architecture.

A new route for the design of renewable hydrogels is presented. The soluble waste from masonite production was isolated, fractionized, and upgraded. The resulting hemicellulose rich fraction was alkenyl-functionalized and used in the preparation of covalently cross-linked hydrogels capable of sustained release of incorporated agents. Said hydrogels showed a Fickian diffusion-based release of incorporated bovine serum albumin. Also, a method for the coating of seeds with hydrogel was developed. The sustained release of incorporated growth retardant agents from the hydrogel coating on rape seeds was shown to enable the temporary inhibition of germination.