Structural engineering of polyurethane coatings for high performance applications

The main objective of this review is to describe some of the important topics related to the use of marine and protective coatings for anticorrosive purposes. In this context, “protective” refers to coatings for containers, offshore constructions, wind turbines, storage tanks, bridges, rail cars, and petrochemical plants while “marine” refers to coatings for ballast tanks, cargo holds and cargo tanks, decks, and engine rooms on ships. The review aims at providing a thorough picture of state-of-the-art in anticorrosive coatings systems. International and national legislation aiming at reducing the emission of volatile organic compounds (VOCs) have caused significant changes in the anticorrosive coating industry. The requirement for new VOC-compliant coating technologies means that coating manufacturers can no longer rely on the extensive track record of their time-served products to convince consumers of their suitability for use. An important aspect in the development of new VOC-compliant, high-performance anticorrosive coating systems is a thorough knowledge of the components in anticorrosive coatings, their interactions, their advantages and limitations, as well as a detailed knowledge on the failure modes of anticorrosive coatings. This review, which mainly deals with European experience and practice, includes a description of the different environments an anticorrosive coating system may encounter during service. In addition, examples of test methods and standards for determination of the performance and durability of anticorrosive coatings have been included. The different types of anticorrosive coatings are presented, and the most widely applied generic types of binders and pigments in anticorrosive coatings are listed and described. Furthermore, the protective mechanisms of barrier, sacrificial, and inhibitive coatings are outlined. In the past decades, several alternatives to organic solvent-borne coatings have reached the commercial market. This review also presents some of these technologies and discusses some of their advantages and limitations. Finally, some of the mechanisms leading to degradation and failure of organic coating systems are described, and the reported types of adhesion loss are discussed.

Anticorrosive coatings: a review

Aromatic disulfide metathesis has been reported as one of the very few dynamic covalent chemistries undergone at room-temperature. Here, bis(4-aminophenyl) disulfide is effectively used as a dynamic crosslinker for the design of self-healing poly(urea–urethane) elastomers, which show quantitative healing efficiency at room-temperature, without the need for any catalyst or external intervention.

Catalyst-free room-temperature self-healing elastomers based on aromatic disulfide metathesis

Produced water is a complex mixture of organic and inorganic compounds and the largest volume of by-product generated during oil and gas recovery operations. The potential of oilfield produced water to be a source of fresh water for water-stressed oil-producing countries and the increasing environmental concerns in addition to stringent legislations on produced water discharge into the environment have made produced water management a significant part of the oil and gas business. This article reviews current technologies for the management of produced water, examines how electrochemical techniques may be used in these areas and compares the prospects for future development. It suggests that treatment technologies based on electrochemistry could be the future of produced water management, since produced water is a potential electrolyte because it has a relatively good conductivity. It also explains that by applying photoelectrochemistry, water electrolysis, fuel cell and electrodeposition, electrochemical engineering could achieve energy storage, production of clean water and recovery of valuable metals from produced water with minimal or no negative impact on the environment.

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Produced water treatment technologies

Microencapsulation is one of the quality preservation techniques of sensitive substances and a method for production of materials with new valuable properties. Microencapsulation is a process of enclosing micron-sized particles in a polymeric shell. There are different techniques available for the encapsulation of drug entities. The encapsulation efficiency of the microparticle or microsphere or microcapsule depends upon different factors like concentration of the polymer, solubility of polymer in solvent, rate of solvent removal, solubility of organic solvent in water, etc. The present article provides a literature review of different microencapsulation techniques and different factors influencing the encapsulation efficiency of the microencapsulation technique.

Microencapsulation techniques, factors influencing encapsulation efficiency

What are Coatings? Polymerization and Film Formation. Flow. Mechanical Properties. Exterior Durability. Adhesion. Corrosion Protection by Coatings. Latexes. Amino Resins. Binders Based on Isocyanates: Polyurethanes. Epoxy and Phenolic Resins. Acrylic Resins. Polyester Resins. Drying Oils. Alkyd Resins. Other Resins and Cross--Linkers. Solvents. Color and Appearance. Pigments. Pigment Dispersion. Pigment Volume Relationships. Application Methods. Film Defects. Solvent--Borne and High Solids Coatings. Water--Borne Coatings. Electrodeposition Coatings. Powder Coatings. Radiation Cure Coatings. Product Coatings for Metal Substrates. Product Coatings for Nonmetallic Substrates. Architectural Coatings. Special Purpose Coatings. Perspectives on Coatings Design. Appendix. Index.

Organic Coatings : Science and Technology

Photoinitiation of cationic polymerization. III. Photosensitization of diphenyliodonium and triphenylsulfonium salts

Laser flash photolysis of diphenyliodonium salts produces phenyliodinium radical cation (PhI+·), which was also generated independently by flash-induced electron transfer from iodobenzene to a phenanthrolinium salt. Apparent second-order rate constants were determined for reaction of the transient (PhI+·) with nucleophiles, including iodobenzene and cyclohexene oxide. Quantum yields of formation of acid from stationary photolysis of diphenyliodonium hexafluoroarsenate were found to be significantly higher than yields of iodobenzene. These results may be explained by facile reaction of PhI+· with PhI to yield a new iodonium salt together with a proton. High reactivity of PhI+· with cyclohexene oxide suggests that the transient may directly initiate cationic polymerization of epoxides.

Photoinitation of cationic polymerization. II. Laser flash photolysis of diphenyliodonium salts

Photoinitiation of cationic and concurrent radicalcationic polymerization. Part V

Preparation de produits d'addition methanne de n-butanol (I) et de diisocyanate d'isophorone en utilisant des quantites inferieures aux quantites equivalentes de (I) et analyse par H-RMN. En presence de catalyseur diazabicyclo [2.2.2] octane, on a le groupe primaire NCO et avec le dilaurate de dibutyletain ou sans addition de catalyseur, on a le groupe secondaire NCO

S. Peter Pappas

Papers

Organic Coatings : Science and Technology

Photoinitiation of cationic polymerization. III. Photosensitization of diphenyliodonium and triphenylsulfonium salts

Photoinitation of cationic polymerization. II. Laser flash photolysis of diphenyliodonium salts

Photoinitiation of cationic and concurrent radicalcationic polymerization. Part V

Relative reactivity of isocyanate groups of isophorone diisocyanate. Unexpected high reactivity of the secondary isocyanate group