Search Results for phenolic linings

This article discusses the coating systems categorized by the generic type of binder or resin and grouped according to the curing or hardening mechanism inherent within that generic type. It focuses on the properties, advantages, and limitations of various autooxidative cross-linked resins, thermoplastic resins, and cross-linked thermosetting resins. The autooxidative cross-linked resins include alkyd resins and epoxy esters. The article examines the two types of coatings based on thermoplastic resins: those deposited by evaporation of a solvent, commonly called lacquers, and those deposited by evaporation of water, a class of coatings called water-borne coatings. The coatings that chemically cross link by copolymerization, including epoxies, unsaturated polyesters, urethanes, high-temperature curing silicones, and phenolic linings, are also described.

Phenols are a class of aromatic organic compounds in which one or more hydroxyl groups are attached directly to the aromatic benzene ring, C6H6. This article describes the development of phenolic resin and the formation of novolac resin and resol resin. Phenolic resol resins are used in interior can coatings and tank linings as well as for heat exchanger tube coatings because of their high chemical and thermal resistance. The article concludes with a description of the concerns that a specifier, user, or applicator should be aware of regarding the use of phenolic coatings.

This article describes the chemistry of phenolic resins and reviews their characteristics and properties for various composites fabrication processes. The fabrication processes include solution/hot-melt process, pultrusion, vacuum infusion, filament winding, sheet molding, and hand lay-up. The article illustrates the manufacturing process of phenolic honeycomb and provides information on the applications of phenolic composites.

Surface coatings are essential in all facilities that process nuclear materials or use nuclear fission for power generation. This article describes the coatings used in two basic types of Generation 3 nuclear reactor designs in the United States and their containment size. These reactors are the boiling water reactor (BWR) and pressurized water reactor (PWR). The article provides information on the loss-of-coolant accident (LOCA) identified as the design basis accident (DBA), which can rapidly de-water the core of an operating nuclear reactor. To avoid LOCA, both the BWR and the PWR include emergency core cooling systems. The article describes a DBA test and other coating performance parameters necessary for safety-related coating systems. It provides a detailed account of the selection criteria of coating types in a nuclear plant. The article concludes by highlighting protective coating strategies in Generation 3 Plants.

This article provides a detailed discussion on the principal classes and curatives of epoxy resins used in the coatings industry. The principal classes are bisphenol A epoxy, bisphenol F epoxy, epoxy phenol novolac, cycloaliphatic epoxies, epoxy acrylate, brominated bisphenol-A-based epoxy, phosphorus-containing epoxy, fluorinated epoxies, epoxy esters, epoxy phosphate esters, and waterborne epoxy. The principal curatives are amines, amine adducts, cyanoethylated amines, ketimines, polyoxyalkylene amines, cycloaliphatic amines, aromatic amines, polyamides, amido amines, and dicyandiamides. Other curatives include polyester co-polymers, phenolic co-polymers, melamine and urea formaldehyde co-polymer resins, phosphate flame retardants, ultraviolet and electron beam curing of epoxy resins, Mannich bases, Mannich-based adducts, and anhydrides. The article concludes by discussing the concerns regarding the use of epoxy coatings.

Bulk molding compounds can be molded into a variety of complex shapes by methods that can be readily automated for high volume production. This article describes the formulation and processing (compound formation, and molding methods) of bulk molding compounds. It discusses the effects of fiber type, fiber length, and matrix type on thermoset bulk molding compounds. The markets for long-fiber-reinforced bulk molding compounds are electrical, ordnance, aerospace, industrial, sporting goods, and automotive applications.

The design and analysis of aerospace and industrial composite components and assemblies requires a detailed knowledge of materials properties, which, in turn, depend on the manufacturing, machining, and assembly methods used. This article, through several tables and graphs, provides the mechanical properties, physical properties, and service characteristics of representative composite fiber-resin combinations, including thermoplastic matrix composites such as thermoplastic polyester resins, thermoplastic polyamide resins, and thermoplastic polysulfone resins, and thermoset matrix composites such as thermoset polyester resins, thermoset phenolic resins, thermoset epoxy resins, thermoset polyimide resins, and thermoset bismaleimide resins.

Hydrochloric acid (HCl) may contain traces of impurities that will change the aggressiveness of the solution. This article discusses the effects of impurities such as fluorides, ferric salts, cupric salts, chlorine, and organic solvents, in HCl. It describes the corrosion resistance of various metals and alloys in HCl, including carbon and alloy steels, austenitic stainless steels, standard ferritic stainless steels, nickel and nickel alloys, copper and copper alloys, corrosion-resistant cast iron, zirconium, titanium and titanium alloys, tantalum and its alloys, and noble metals. The article illustrates the effect of HCl on nonmetallic materials such as natural rubber, neoprene, thermoplastics, and reinforced thermoset plastics. It also tabulates the corrosion of various metals in dry hydrogen chloride.

This article discusses the materials and properties of polymer-matrix composites to characterize each generic material according to its composition and method of manufacture. It contains a table that lists the key physical, mechanical, thermal, and electrical properties, and in-service conditions of concern for resin-matrix composites. Axes definitions, symbols, and special property calculations for composite material property tests are reviewed. The article provides an overview of the performance capabilities of selected polymer-matrix composite materials such as thermoplastic-matrix composites and thermoset-matrix composites. The thermoplastic-matrix composites include thermoplastic polyester resins and fiber resin composites; thermoplastic polyamide resins and fiber-resin composites; and thermoplastic polysulfone resins and fiber-resin composites.

This article describes the paint systems generally used to protect steel structures, steel sheet, and bridges from corrosion, and how they deter corrosion. It provides a discussion on the basic design criteria of steel structures for corrosion protection. The article also explains the differences between prepaint and postpaint, and the steps involved in prepaint processing of steel. It presents the selection guideline for paint system evaluation. The advantages of corrosion protection are also discussed.

This article discusses classification of foundry processes based on the molding medium, such as sand molds, ceramic molds, and metallic molds. Sand molds can be briefly classified into two types: bonded sand molds, and unbonded sand molds. Bonded sand molds include green sand molds, dry sand molds, resin-bonded sand molds, and sodium silicate bonded sand. The article describes the casting processes that use these molds, including the no-bake process, cold box process, hot box process, the CO2 process, lost foam casting process and vacuum molding process. The casting processes that use ceramic molds include investment casting, and plaster casting. Metallic molds are used in permanent mold casting, die casting, semisolid casting, and centrifugal casting.

No-bake sand molds are based on the curing of inorganic or organic binders with either gaseous catalysts or liquid catalysts. This article reviews the major aspects of no-bake sand bonding in terms of coremaking, molding methods, and sand processing. It discusses the points to be noted in handling sand-resin mixtures for no-bake molds or cones and lists some advantages of no-bake air-set cores and molds. The article describes the process procedures, advantages, and disadvantages of gas curing and air-setting hardening of sodium silicates. It examines the members of the air-setting organic binders, namely, furan no-bake resins, phenolic no-bake resins, and urethanes. The article provides an overview of gas-cured organic binders. It also illustrates the three commercial systems for sand reclamation: wet reclamation systems, dry reclamation systems, and thermal reclamation.

This article begins with an overview of the fundamentals of adhesive technology, including functions, limitations, adhesive joint types, and the key factors in the selection of adhesives, including application, type of joint, process limitation, mechanical requirement, and service conditions. It then focuses on the characteristics, types, and properties of the five groups of adhesives, such as structural, hot melt, pressure sensitive, water based, ultraviolet, and electron beam cured adhesives. The article also discusses the functions and applications of adhesive modifiers, including fillers, adhesion promoters, tackifiers, and tougheners. It gives a short note on functions of primers and primerless bonding. Applications of adhesives in automotive, aerospace, electronics, electrical, medical, sports, and construction sectors are also described. Finally, the article describes the steps in adhesive bonding, including storage and handling of adhesives, bonding preparation, adhesive application, tooling, and curing.

A thermosetting resin, or thermoset, is a synthetic organic polymer that cures to a solid, infusible mass by forming a three-dimensional network of covalent chemical bonds. Significant applications include construction and thermoset engineering plastics. This article discusses the general and family characteristics of thermosetting resin families, including allyls, aminos (urea formaldehyde and melamine formaldehyde), cyanates, epoxies, polybenzimidazoles, unsaturated polyesters, thermoset polyimides, phenolics, and vinyl esters. It also explains processing methods, including curing and curing agents. The article provides descriptions of commercial product forms and the wide array of applications of thermosetting resins. It also tabulates the performance properties (mechanical, thermal, electrical and chemical resistance) of some families of unfilled or unreinforced thermosetting resins and reinforced or filled grades.

Cores are separate shapes of sand that are placed in the mold to provide castings with contours, cavities, and passages that are not otherwise practical or physically obtainable by the mold. This article describes the basic principles of coremaking and the types of core sands, binders, and additives used in coremaking. It discusses the curing of compacted cores by core baking and the hot box processes. The article provides an overview of the core coatings, assembling and core setting, coring of tortuous passages, and cores in permanent mold castings and investment castings. It also discusses the design considerations in coremaking to eliminate cores and compares coring with drilling.

This article describes the selection of materials for the production and handling equipment of concentrated sulfuric acid, depending on factors such as the allowable corrosion rate, desired mechanical and physical properties, fabrication requirements, availability, and cost. Materials such as carbon steel, cast irons, austenitic stainless steels, higher austenitic stainless steels, higher chromium Fe-Ni-Mo alloys, nickel-base alloys, non-metals, and specific other metals and alloys are also discussed.

This article provides a detailed discussion on the functions, applications, types, and selection criteria of exterior and interior rail coatings. It includes a discussion on the corrosivity, inspection/maintenance, and qualification of applicators/inspectors/facilities.

This article describes the resin and fabrication requirements associated with fiberglass-reinforced plastic equipment. It provides a discussion on various resins and their resistance to various environments. These include polyester, epoxy, epoxy vinyl-ester, and furan and phenolic thermosetting resins. The article concludes with a discussion on the curing system of thermosetting resins.