Electron Microscope Investigation of States of Distribution in Elastomer Blends

High polymers that possess high elastic deformability are referred to as elastomers. They have a glass transition between —40° and —70° C. Uberreiter1 has appropriately described their aggregate state as “liquid with fixed structure”, since within the temperature range of elastic deformability individual chain segments of a macromolecule do describe, to be sure, a disordered temperature motion, corresponding to that found in liquids. Yet the macromolecule as a whole is not mobile, because of strong intermolecular forces. When elastomer blends are prepared by mixing the components on a mill or in an internal mixer, technical interest is mainly limited to technological properties, such as softening point, shear modulus, abrasion, etc. But it also seems important to obtain information about the distribution of the components in the blends, in order to evaluate more accurately the basic miscibility of elastomers in general, as well as the intrinsic strength of such multi-phase systems. A solution to the problem may best be obtained by electron microscope investigations since they permit observation of very minute structures representing constant and characteristic values for a given polymer, and can thus serve as a means of identifying a given polymer, even in mixtures. Schoon and Kretschmer have already found that a relation exists between microstructure (observed with an electron microscope) and molecular weight of high polymers.