ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

The macromolecular-free radical degradation level in the thermal degradation of polydienes as revealed by the electron-spin-resonance method

A. Tkáč, Z. Frait, and M. Ondris

Slovak Technical University, Bratislava

Abstract: The initiation and termination of macromol. free radicals in various natural rubbers and in polyisoprene were studied in the solid state from - 150 to 200°. Degradation at higher temps. was responsible for the resonance signal with g = 2.2, resulting from the absorption of the microwave component of 9200 Mc./sec. at 2900 oe. With increasing temp., the original spectral width of ΔH 200-300 narrows to 80-100 oe., which is connected with reduction of the interaction forces. With α,α-diphenyl-β-picrylhydrazyl used as an internal standard, the reversible shift of 100-150 oe. to the free-electron region was observed after increasing the temp. to 200°. Accordingly, g decreased from 2.23 to 2.14. 18 references.

Full paper in Portable Document Format: 172a81.pdf (in Slovak)

Chemical Papers 17 (2) 81–94 (1963)