Search Results for cross-linked thermosetting resins

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.

A coating can be defined as a substance spread over a surface to provide protection or to serve decorative purposes. This article discusses two industrial coating components, namely, nonvolatile components such as the resin or binder, pigments, and any additives that may be incorporated into the formulation; and volatile components such as solvents, or water in emulsions and their composition. It provides general information on volatile organic compounds. The article describes the film-forming mechanisms of various coating types, namely, lacquers, chemically converting coatings, latex coatings, alkyds and other resins, which cure by oxidation, moisture-curing polyurethanes and inorganic zinc primers, and powder coatings. The article concludes with a discussion on the functions of the primer, intermediate coat, and topcoat in coating systems.

This article discusses the most common thermal analysis methods for thermosetting resins. These include differential scanning calorimetry, thermomechanical analysis, thermogravimetric analysis, and dynamic mechanical analysis. The article also discusses the characterization of uncured thermosetting resins as well as the curing process. Then, the techniques to characterize the physical properties of cured thermosets and composites are presented. Several examples of stress-strain curves are shown for thermosets and thermoplastic polymers.

This introductory article describes the various aspects of chemical structure that are important to an understanding of polymer properties and thus their eventual effect on the end-use performance of engineering plastics. The polymers covered include hydrocarbon polymers, carbon-chain polymers, heterochain polymers, and polymers containing aromatic rings. The article also includes some general information on the classification and naming of polymers and plastics. The most important properties of polymers, namely, thermal, mechanical, chemical, electrical, and optical properties, and the most significant influences of structure on those properties are then discussed. A variety of engineering thermoplastics, including some that are regarded as high-performance thermoplastics, are covered in this article. In addition, a few examples of commodity thermoplastics and biodegradable thermoplastics are presented for comparison. Finally, the properties and applications of six common thermosets are briefly considered.

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.

This article describes the most significant tests to characterize the properties of constituent materials. It discusses the chemical, physical, and mechanical tests for determining the properties of reinforcement fibers and fabrics. The article provides information on some of the basic materials used for thermoset and thermoplastic resin matrices. It reviews the identification of the individual characteristics of thermoset and thermoplastic resin along with the test methods normally used for their determination. The article contains a table that lists properties and tests for uncured and cured thermoset-matrix resins and prepregs.

This article outlines the fundamentals of polymer science and emphasizes the aspects that are necessary and useful to applications of engineering plastics. The basic structure of polymers influences the properties of both polymers and the plastics made from them. An understanding of this basic structure permits the engineers to understand which polymers may be acceptable for a certain application, and which may not. There are various possible classification schemes for polymers. Typical classification categories include polymerization process, chemical elements that make up the monomer, or crystalline versus noncrystalline structure. The article describes the various aspects of chemical structure that are important to an understanding of polymer properties and, thus, affect eventual end uses. It discusses different types of names assigned to polymers. The article details the aspects of polymer structure and examines the properties of polymers and the way they are altered by structure.

This article provides a discussion on polyester coating applications such as powder coatings, can coatings, and automotive paints. It includes an overview, structure, properties, and benefits of vinyl ester resins. The article discusses the additives for both unsaturated polyester and vinyl ester coatings, namely, curing systems, thixotropic agents and fillers. It exemplifies polyester and vinyl ester coating, lining and flooring systems that are used for top-to-bottom protection of industrial plants and equipment. The article also highlights the concerns to be addressed when using polyesters and vinyl esters.

Thermal analysis provides a powerful tool for researchers and engineers in determining both unknown and reproducible behavioral properties of polymer molecules. This article covers the thermal analysis and thermal properties of engineering plastics with respect to chemical composition, chain configuration, conformation of the base polymers, processing of the base polymers with or without additives; and the response to chemical, physical, and mechanical stresses of base polymers as unfilled, shaped articles or as components of composite structures. It also describes thermal analysis techniques, including differential scanning calorimetry, thermogravimetric analysis, thermomechanical analysis, and rheological analysis. This article also summarizes the basic thermal properties used in the application of engineering plastics, such as thermal conductivity, temperature resistance, thermal expansion, specific heat, and the determination of glass transition temperatures. It concludes with a discussion of the thermal and related properties of nine thermostat resin systems divided into three groups by low, medium, and high service temperature capabilities.

This article discusses the thermal properties of engineering plastics and elastomers with respect to chemical composition, chain configuration, and base polymer conformation as determined by thermal analysis. It describes the processing of base polymers with or without additives and their response to chemical, physical, and mechanical stresses whether as an unfilled, shaped article or as a component of a composite structure. It summarizes the basic thermal properties of thermoplastics and thermosets, including thermal conductivity, temperature resistance, thermal expansion, specific heat, and glass transition temperature. It also provides information on polyimide and bismaleimide resin systems. Representative examples of different types of engineering thermoplastics are discussed primarily in terms of structure and thermal properties.

Molding compounds are plastic materials in varying stages of pellets or granulation that consist of resin, filler, pigments, reinforcement, plasticizers, and other ingredients ready for use in a molding operation. This article describes the material components and physical properties of sheet molding compounds (SMC). The three types of resin paste mixing techniques, such as batch, batch/continuous, and continuous, for an SMC operation are reviewed. The article discusses the design features and functional operations of the two types of SMC machines, namely, continuous-belt and beltless machines. It explains the formulation and processing of bulk molding compounds and reviews molding methods for bulk molding compounds, including compression, transfer, and injection molding. The effects of the fiber type and length and the matrix type on thermoset bulk molding compounds are discussed. It describes the four injection molding processes of injection molding compounds such as feeding, transporting, injecting, and flowing.

This article describes the dispersed-phase toughening of thermoset matrices by the development of multiphase-structure thermosetting matrices using rubber and/or thermoplastic materials. It discusses two main methods for manufacturing prepregs, namely, single-pass impregnation and double-pass impregnation. The article illustrates reflected-light optical microscopy techniques to evaluate the morphology of thermoplastic materials for determining the material quality and correlating key microstructural features with material performance.

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.

Microstructural analysis of the composite matrix is necessary to understand the performance of the part and its long-term durability. This article focuses on the microstructural analysis of engineering thermoplastic-matrix composites and the influence of cooling rate and nucleation on the formation of spherulites in high-temperature thermoplastic-matrix carbon-fiber-reinforced composites. It also describes the microstructural analysis of a bio-based thermosetting-matrix natural fiber composite system.

This article describes methods for analyzing impact-damaged composites in the aircraft industry. These include C-scan and x-radiography methods and optical microscopy. The article reviews brittle-matrix composite and tough-matrix composite failures. It explains the different types of composite failure mechanisms such as thermoplastic-matrix composite failure mechanisms, untoughened thermoset-matrix composite failure mechanisms, toughened thermoset-matrix composite failure mechanisms, dispersed-phase and rubber-toughened thermoset-matrix composite failure mechanisms, and particle interlayer-toughened composite failure mechanisms.

Adhesive bonding is a proven technology in the manufacture of automotive assemblies, helping carmakers achieve weight reduction goals without compromising body stiffness, crash performance, and noise-vibration-handling characteristics. This article discusses the advantages and limitations of adhesive-bonded aluminum joints and the procedures used to produce them. It addresses surface preparation, the addition of interfacial coatings and primers, and the application of thermoplastic and thermosetting resins. The article examines the nature and role of the various layers that constitute the joint and explains how each contributes to performance. It also discusses adhesive selection factors, joint design, and testing procedures.

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 focuses on various thermal analysis techniques used to verify the cure of a polymer composite. The techniques include differential scanning calorimetry (DSC), modulated DSC, thermomechanical analysis, dynamic mechanical analysis, and dielectric analysis. The article also provides an overview of the composite failure modes affected by matrix resin and testing approach.

This article discusses the three basic elements of an epoxy resin formulation that must be understood when selecting a thermoset system. These include base resins, epoxy resin curatives, and modifiers. The article provides examples of epoxy resin formulations that illustrate how raw materials are combined to tailor a formulation to a specific application. It concludes with a discussion on general guidelines for the safe handling of epoxy resins and their associated products.

This article presents a comprehensive collection of the definition of terms related to metallurgy.