Twenty years of physics: High‐polymer physics

STUDY OF ORGANIC polymers in the solid state began in the early 1920’s with x‐ray investigation of natural representatives such as cellulosic fibers, starch, silk, wool, rubber and certain resins; the general, qualitative result was that all these materials, despite their chemical dissimilarity, produce x‐ray diffraction patterns indicating a certain degree of molecular regularity. Together with the concept of substantially linear chain‐like macromolecules, these findings led to the conclusion that, in the polymeric solid state, there are volume elements or domains with essentially parallel chains. They have a three‐dimensional geometrical regularity that resembles the structure of a crystal. Other volume elements, however, are occupied by other portions of the same chains; here individual segments are irregularly arranged so that these domains possess the structural characteristics of a liquid or a glass.