Search Results for polymer testing

This article briefly describes the historical development of fracture resistance testing of polymers and reviews several test methods developed for determining the fracture toughness of polymeric materials. The discussion covers J-integral testing, the methods for determining linear elastic fracture toughness, testing of thin sheets and films, normalization methods, and hysteresis methods.

This article describes the basic approaches to improving the fire resistance of a polymeric material, considers the burning process on a microscale and macroscale, and discusses various test methods for determining the flammability characteristics of polymeric materials. Test methods are classified in two ways: by fire response characteristics and by particular applications of polymeric materials.

Structural and fracture mechanics-based tools for metals are believed to be applicable to nonmetals, as long as they are homogeneous and isotropic. This chapter discusses the essential aspects of the fatigue and fracture behaviors of nonmetallic materials with an emphasis on how they compare with metals. It begins by describing the fracture characteristics of ceramics and glasses along with typical properties and subcritical crack growth mechanisms. It then discusses the properties of engineering plastics and the factors affecting crack formation and growth, fracture toughness, fatigue life, and stress rupture failures.

This chapter presents the fundamentals of tensile testing of fiber-reinforced polymer composites. Basic tensile testing of polymer composites is divided into lamina and laminate testing. The chapter focuses on tensile testing of laminates. It discusses the most common tensile test methods that have been standardized for fiber-reinforced composite materials. It also briefly reviews considerations in tensile testing of metal-matrix composites.

This chapter details low-temperature test procedures and equipment. It discusses the role temperature plays in the properties of typical engineering materials. The effect that lowering the temperature of a solid has on the mechanical properties of a material is summarized for three principal groups of engineering materials: metals, ceramics, and polymers (including fiber-reinforced polymers). The chapter describes the factors that influence the selection of tensile testing procedures for low-temperature evaluation, along with a comparison of tensile and compression tests. It covers the parameters and standards related to low-temperature tensile testing. The chapter discusses the factors involved in controlling test temperature. Finally, the chapter discusses the safety issues concerning the use of cooled methanol, liquid-nitrogen, and liquid helium.

This article briefly introduces some commonly used methods of mechanical testing of plastics for determining mechanical properties, also describing the test methods and providing comparative data for the mechanical property tests. In addition, creep testing and dynamic mechanical analyses of viscoelastic plastics are briefly described. The discussion covers the most commonly used tests for impact performance, various types of hardness test for plastics, the fatigue strength of viscoelastic materials, and the tension testing of elastomers and fibers.

This chapter covers the fatigue and fracture behaviors of ceramics and polymers. It discusses the benefits of transformation toughening, the use of ceramic-matrix composites, fracture mechanisms, and the relationship between fatigue and subcritical crack growth. In regard to polymers, it covers general characteristics, viscoelastic properties, and static strength. It also discusses fatigue life, impact strength, fracture toughness, and stress-rupture behaviors as well as environmental effects such as plasticization, solvation, swelling, stress cracking, degradation, and surface embrittlement.

This article is a detailed account of the mechanisms of fatigue failure of polymers, namely thermal fatigue failure and mechanical fatigue failure. The mechanical fatigue failure is discussed in terms of fatigue crack initiation and fatigue crack propagation.

This article discusses the molecular mechanism, environmental criteria, and material optimization of environmental stress crazing (ESC) in glassy thermoplastics, polyethylenes, and nylons. In addition, it provides information on various tests used to determine relative susceptibility to ESC, namely constant tensile load testing and constant-strain testing.

This article introduces the subject of fractography and how it is used in failure analysis. The discussion covers the structure of and fracture and crack-propagation behavior of polymeric materials, the distinction between the ductile and brittle fracture modes on the basis of macroscopic appearance, and the examination and interpretation of the features of fracture surfaces. In addition, the article considers several cases of field failure in various polymers to illustrate the applicability of available analytical tools in conjunction with an understanding of failure mechanisms.

This article reviews fatigue test methodologies, provides an overview of general fatigue behavior (crack initiation and propagation) in engineering plastics, and discusses some of the factors affecting the fatigue performance of polymers. In addition, it provides information on fractography that provides useful insight into the nature of fracture processes.

This article addresses some established protocols in characterizing thermoplastics, whether they are homogeneous resins, alloyed or blended compositions, or highly modified thermoplastic composites. It begins with a description of various approaches used for the determination of molecular weight (MW) by viscosity measurements. This is followed by a discussion of the use of cone and plate and parallel plate geometries in determining the viscoelastic properties of a polymer melt. Details on some of the chromatographic techniques that allow determination of MW and MW distribution of polymers are then provided. The article concludes with information on three distinctive, but complementary operations of thermoanalytical techniques, namely differential scanning calorimetry, thermogravimetric analysis, and thermomechanical testing.

This chapter discusses the use of thermoset and thermoplastic resins in polymer matrix composites. It begins by explaining how the two classes of polymer differ and how it impacts their use as matrix materials. It then goes on to describe the characteristics of polyester, vinyl ester, epoxy, bismaleimide, cyanate ester, polyimide, and phenolic resins and various toughening methods. The chapter also covers thermoplastic matrix materials and product forms and provides an introduction to the physiochemical tests used to characterize resins and cured laminates.