Brunner, A. J., Hack, E., & Neuenschwander, J. (2008). Nondestructive testing. In A. Seidel (Ed.), Characterization and analysis of polymers (pp. 357-377).
Polymers are macromolecules that contain repetitive, regular or irregular arrangements of organic molecular groups, ie, carbon atoms covalently bonded with other carbon and/or heteroatoms. Technical polymers usually contain additives, fillers, and pigments. Polymer-matrix composites (PMC) contain at least a second, insoluble phase, frequently in the form of fibers or particles. The structure and morphology of polymers and PMC can be quite complex; see, eg, AMORPHOUS POLYMERS; SEMICRYSTALLINE POLYMERS; MORPHOLOGY, ADDITIVES, VISCOELASTICITY, PHASE TRANSFORMATION, and Reference 1. Properties of polymers and PMC that may be relevant for nondestructive testing (NDT) are as follows: (1) (pronounced) temperature dependence, viscoelastic behavior, and, in some cases, specific transition temperatures; (2) limited thermal stability, upper limit set by incipient decomposition or melting; (3) relatively low density; (4) transparency, semitransparency, or opaqueness with respect to the visible part of the electromagnetic spectrum; (5) electrical insulation and relatively low electrical conductivity for specially formulated compositions; and (6) possible changes in volume, properties, and, in some cases, even chemical reactions induced by absorption or diffusion of media. [...]