X-RAY STUDY ON TELECHELIC COPOLYMERS OF BUTADIENE AND METHACRYLIC-ACID

In the reported experiments, the telechelic polybutadiene-methacrylic acid copolymer (Hycar CTB) containing 2 mole percent acid and neutralized (5-100%) by alkali ions, Na** plus , K** plus , and Cs** plus , has been studied by small-angle x-ray scattering. Salt groups form clusters, and the average value of the radii of gyration is approximately 8 A; this value seems to be independent of the nature of the cation and the degree of neutralization. The existence of a low-angle maximum in the scattering intensity gives evidence of a mean distance of 80 A between clusters in the fully neutralized sample. This distance increases slightly with a decreasing degree of neutralization. A more precise analysis of the small-angle scattering curve gives further information on the cluster structure: the ionic groups may form small bilayer disks while the polymer chains maintain a regular distance of 80 A between the disks.