Diels-Alder polymerization of some derivatives of abietic acid

Citation
I. Bicu et F. Mustata, Diels-Alder polymerization of some derivatives of abietic acid, ANGEW MAKRO, 264, 1999, pp. 21-29
Citations number
13
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
ANGEWANDTE MAKROMOLEKULARE CHEMIE
ISSN journal
00033146 → ACNP
Volume
264
Year of publication
1999
Pages
21 - 29
Database
ISI
SICI code
0003-3146(199902)264:<21:DPOSDO>2.0.ZU;2-5
Abstract
The Diels-Alder polymerization reaction between a bisdiene derived from abi etic acid and 4,4'-diphenylmethanedimaleimide (bismaleimide) was studied. T he bisdiene was the dehydrodecarboxylation product of abietic acid, denoted here as diabietyl ketone. An insoluble and infusible polymer with high mol ecular weight was obtained. It is a poly(ketoimide) with hydrophenanthrene moieties in the backbone. The analyses showed that the chemical structure o f the polymer was different from that expected. The polymer structural unit was found to contain bismaleimide and diabietyl ketone units not in a mola r ratio of 1:1, as expected, but in a ratio of 5-6:1. The phenomenon was as cribed to the difference between the rates of the two concomitant reactions in the synthesis; the homopolymerization of bismaleimide and the proper Di els-Alder polymerization. The polymer having in structure the monomer units in 1:1 ratio was, however, obtained by both the dehydrodecarboxylation of the diacid resulted from the Diels-Alder reaction between abietic acid and 4,4'-diphenylmethanedimaleimide and the polycondensation of the ketone of m aleated abietic acid with 4,4'-diaminodiphenylmethane. The monomers and the polymers were investigated by usual physical and chemical methods. The the rmal stability of polymers was evaluated by TGA. The synthesized polymers w ere identical heat-resistant as the crosslinked polymer obtained from 4,4'- diphenylmethanedimaleimide. They were stable in air up to 360 degrees C.