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

Decay of macroradicals in poly(methyl methacrylate) crosslinked with aliphatic diamines

M. Klimová, J. Pavlinec, and F. Szőcs

Polymer Institute. Centre for Chemical Research, Slovak Academy of Sciences, CS-842 36 Bratislava

Abstract: Free radicals were generated by gamma-irradiation and mechanical destruction of solid poly(methyl methacrylate) (PMMA) samples crosslinked with aliphatic diamines (1,3-diaminopropane and 1,12-diaminododecane) which have a different number of CH₂ groups in a molecule. The effects of the method of free radicals generation, crosslinks density and the character of crosslinking agent on kinetic parameters of decay of chain-end PMMA macroradicals have been investigated. For temperatures T> 323 K, the values of apparent activation energy of the decay of chain-end macroradicals rise with an increase of the initial amount of aliphatic amine, and thus with a crosslinks density, up to 0.8 mass % of amine used. 1,12-Diaminododecane yields a crosslinked structure in which apparent activation energies of free radicals decay are higher than those with 1,3-diaminopropane, irrespective of the method of free radicals generation. A similar trend of the increase of apparent activation energy can be observed with an increasing concentration of crosslinking agents for both the mechanical and irradiation method of free radicals generation, the former method giving lower activation energies.

Full paper in Portable Document Format: 443a399.pdf

Chemical Papers 44 (3) 399–408 (1990)