M. Delucchi, G. Cerisola
Influence of organic coatings on the stability of macrodefect-free cements exposed to water
Construction and Building Materials , 15 (2001) 351-359

ABSTRACT
It is known that macrodefect-free (MDF) cements show instability in water, with swelling and reduction in strength. The weight and dimensional changes of three MDF cements, formulated from different aluminous cements, during immersion in quiescent tap water, were evaluated. The results show that the cement with the highest Al2O3 percentage had the lowest degradation after prolonged immersion. Hence, this material was selected for further analysis. As the time taken for water to diffuse into the body of MDF composites is considered a key factor in the collapse of their mechanical properties, the effect of organic coatings with different barrier properties on the composite behaviour, when exposed to water, was studied. The water permeability of seven surface coatings was evaluated by electrochemical impedance spectroscopy (EIS). Three of them were chosen for application to the selected MDF cement. The data presented show that the application of organic coatings, not necessarily characterised by extremely low water permeabilities, improves the stability of the composite when subjected to different conditions of exposure to water.

J. Iniesta, P.A. Michaud, M. Panizza and Ch. Comninellis
Electrochemical oxidation of 3-methylpyridine at a boron-doped diamond electrode: Application to electroorganic synthesis and wastewater treatment
Electrochemistry Communications, 3 (2001) 346-351

ABSTRACT
The electrochemical oxidation of 3-methylpyridine (3-MP) at synthetic boron-doped diamond thin film electrode (BDD) has been studied in acid media by cyclic voltammetry and bulk electrolysis. The results have shown that in the potential region of water stability they can occur direct electron transfer reactions on BDD surface that results in electrode fouling due to the formation of a polymeric film on its surface. While during electrolyses in the potential region of water decomposition, indirect oxidation reactions can take place by electrogenerated active intermediates, probably hydroxyl radicals that can avoid electrode fouling. Depending on the values of applied current density, it is possible to obtain the partial oxidation of 3-MP to nicotinic acid or the complete combustion of 3-MP to CO2.

M.A. Rodrigo, P.A. Michaud, I.Duo, M. Panizza, G. Cerisola, Ch. Comninellis
Oxidation of 4-Chlorophenol at Boron-Doped Diamond electrodes for Wastewater Treatment
Journal of Electrochemical Society 148 (2001) D60-D64

ABSTRACT
The electrochemical behavior of synthetic boron-doped diamond thin film electrode (BDD) has been studied in acid media containing 4-chlorophenol (4-CP) by cyclic voltammetry, chronoamperometry and bulk electrolysis. The results have shown that in the potential region of supporting electrolyte stability they occur reactions involving simple electron transfer, such as oxidation of 4-CP to phenoxy radical and 1,4-benzoquinone. Polymeric materials, which result in electrode fouling, are also formed in this potential region. While during electrolysis in the potential region of electrolyte decomposition, complex oxidation reactions can take place electrodes by electrogenerated hydroxyl radicals leading to the complete incineration of 4-chlorophenol. Electrode fouling is inhibited under these conditions. The experimental results have been also compared with a theoretical model. Finally, HPLC analyses have been reveled that the main intermediate products of 4-CP oxidation were 1,4-benzoquinone, maleic acid, formic acid and oxalic acid.

M. Delucchi, G. Cerisola
Crack-bridging ability of organic coatings on concrete
Protective Coatings Europe 6 (2001) 44-48
Journal of Protective Coatings and Linings 18 (2001) 44-48

M. Panizza, P. A. Michaud, G. Cerisola, Ch. Comninellis
The Anodic Oxidation of 2-Naphthol at Boron-Doped Diamond electrodes
Journal of Electroanalytical Chemistry, 507 (2001) 206-214

ABSTRACT
The anodic oxidation of 2-naphthol in acid media was investigated at a synthetic boron-doped diamond thin film electrode (BDD) using cyclic voltammetry and bulk electrolysis. The results have shown that in the potential region, where the supporting electrolyte is stable, reactions involving simple electron transfer, such as oxidation of 2-naphthol to naphthoxy radical and 1,4-naphthoquinone occur. Polymeric materials, which lead to electrode fouling, are also formed in this potential region. Electrolysis at high positive potentials in the region of electrolyte decomposition causes complex oxidation reactions by electrogenerated hydroxyl radicals leading to the complete incineration of 2-naphthol. Electrode fouling is inhibited under these conditions. The experimental results have been also compared with a theoretical model. This model is based on the assumption that the rate of the anodic oxidation of 2-naphthol is a fast reaction and it is under diffusion control.

T. Temtchenko, S. Turri, S. Novelli, M. Delucchi
New developments in perfluoropolyether resins technology: high solid and durable polyurethanes for heavy duty and clear oem coatings
Progress in Organic Coatings, 43 (2001) 75-84

ABSTRACT
Recent advances in perfluoropolyether (PFPE) resin technology for high solids, weather resistant polyurethanes for automotive (OEM) and heavy duty coatings are presented. In the former case, polyfunctional OH-terminated PFPE resins can be successfully blended with commercially available blocked isocyanates leading to high solids (70¯80 wt.%) monocomponent polyurethanes with high density of cross-linking. Formulations containing PFPE resins and mixed hexamethylene diisocyanate/isophorone diisocyanate (HDI/IPDI) blocked isocyanates were prepared and characterized according to OEM specifications; the performances of fluorinated coatings were compared with those of reference acrylic solvent-borne coatings. Clearcoats were applied over conventional OEM basecoats (car body painting) and polyester powder coatings (wheels painting). The remarkable improvement of anticorrosion performances, acid and mar resistance and durability of painting system was reached maintaining its good aesthetic aspect. Fluorinated films showed excellent stain release properties conferring to final painting system, the self-cleaning behaviour typical for PFPE coatings. In the latter case, the use of dihydroxy terminated PFPE oligomers having properly selected molecular weights and bimodal molecular weight distribution allowed the preparation of really high solid (80¯90 wt.% dry) low viscosity formulations with aliphatic and cycloaliphatic hydrogenated polyisocyanates. The compositions were able to cross-link rapidly even at temperatures below 20°C giving fully transparent, chemically resistant and easy-cleanable coatings. The coating physical properties like hardness, glass transition temperature (Tg) and elongation can be optimized by tuning the hardener composition (HDI/IPDI ratio) as well as the molecular weight of the PFPE. White pigmented, high gloss finishes were also prepared and evaluated as protective barrier coating for heavy duty paints working in highly corrosive environments.

M. Panizza, P. A. Michaud, G. Cerisola, Ch. Comninellis
Electrochemical treatment of wastewaters containing organic pollutants on boron-doped diamond electrodes. Prediction of specific energy consumption and required electrode area
Electrochemistry Communications, 3 (2001) 336-339

ABSTRACT
A theoretical analysis is presented for the prediction of the specific energy consumption and the required electrode surface for the electrochemical combustion of organic compounds on synthetic boron-doped diamond (BDD) thin film electrodes. The model is formulated for a perfect mixed electrochemical reactor operated as a batch recirculation system under galvanostatic conditions. The anodic oxidation of organics is assumed to be under diffusion control. An experimental validation with the anodic oxidation of phenol and under different experimental conditions is also provided.

T. Temtchenko, S. Novelli, M. Delucchi, G. Cerisola
New fluorinated protective coatings
Pitture e Vernici Europe, 77 (2001) 15-20

A. Barbucci, M. Delucchi, M. Panizza, M. Sacco, G. Cerisola
Electrochemical and corrosion behaviour of cold rolled AISI 301 in 1 M H₂SO₄
Journal of Alloys and Compounds , 317-318 (2001) 607-611

ABSTRACT
Stainless steels (SS) are widely used in several fields. In recent years, the good corrosion resistance as well as the remarkable mechanical properties of SS have made it an even more utilised material. Such extensive utilisation produces new concern about its ability to maintain good properties after many working processes. In this paper an AISI 301 SS with different degrees of cold deformation has been considered. The cold working of these materials produces some important changes in the microstructure (i.e. grain size, crystallographic texture) and involves phase transformations. Electrochemical measurements have been used to investigate the corrosion behaviour of the alloy in sulphuric acid in the presence of chlorides. In the anodic behaviour of the cold rolled with respect to the annealed SS, a moderate variation of the passivity region but a remarkable increase of the current density was observed. Morphological analyses have been performed to relate the electrochemical results to the alloy structure. The relationship between metallurgical properties and corrosion behaviour has been discussed.

L. Gherardini, P.A. Michaud, M. Panizza, Ch. Comninellis, N. Vatistas
Electrochemical Oxidation of 4-Chlorophenol for wastewater treatment. Definition of Anode Activity Parameter
Journal of Electrochemical Society 148 (2001) D78-D82

ABSTRACT
The electrochemical behavior of lead dioxide and synthetic boron-doped diamond thin film electrode (BDD) has been studied in acid media containing 4-chlorophenol by bulk electrolysis under different experimental conditions. The results have shown that even if the complete incineration of 4-chlorophenol has been obtained both with lead dioxide anode and boron doped diamond anode, the latter has given higher current efficiencies. Furthermore, a new parameter, the anode activity for the electrochemical oxidation has been also introduced. It can be defined as the ability of the anode to promote the electro-oxidation and to reduce the side reaction of oxygen evolution and it takes into consideration the mass transfer limitation of the organic species to the anode surface. It has been shown that the anode activity depends on the system anode material / organic species but it is independent on the operating conditions.

M. Panizza, G. Cerisola
Removal of organic pollutants from industrial wastewater by electrogenerated Fenton's reagent
Water Research 35 (2001) 3987-3992

ABSTRACT
This study was performed to investigate the treatment of an industrial wastewater mainly containing naphthalene- and anthraquinone-sulphonic acids, by electrogenerated Fenton's reagent. The hydrogen peroxide was produced in situ by electrochemical reduction of oxygen on graphite-felt cathodes and the Fe2+ ions were also regenerated by cathodic reduction of Fe3+. The influence of cathode potential, Fe2+ concentration and electrode surface pre-treatment on chemical oxygen demand (COD) removal and color fading were studied. Results indicated that the higher COD removal was obtained in the presence of 3 mM of ferrous ions working at a constant potential of -1V vs. SCE. Moreover, it was shown that both chemical and electrochemical pre-treatments of cathode surface resulted in a decrease of COD depletion.

J. Iniesta, P.A. Michaud, M. Panizza, G. Cerisola, A. Aldaz and Ch. Comninellis
Electrochemical oxidation of phenol at boron-doped diamond electrode
Electrochimica Acta 46 (2001) 3573-3578

ABSTRACT
The electrochemical oxidation of phenol at synthetic boron-doped diamond thin film electrode (BDD) has been studied in acid media by cyclic voltammetry, chronoamperometry and bulk electrolysis. The results have shown that in the potential region of water stability (E<2.3 V vs. SHE) they can occur direct electron transfer reactions on BDD surface that results in electrode fouling due to the formation of a polymeric film on its surface. While during electrolyses in the potential region of water decomposition (E>2.3 V vs. SHE), indirect oxidation reactions can take place by electrogenerated active intermediates, probably hydroxyl radicals, which can avoid electrode fouling. Depending on the values of applied current, and phenol concentration it is possible to obtain the complete combustion of phenol to CO2 or the partial oxidation of phenol to other aromatic compounds (benzoquinone, hydroquinone, catechol).