STUDY OF BULK CHAIN COUPLING REACTIONS .2. REACTION BETWEEN BISOXAZOLONES AND AMINE-TERMINATED POLYETHER - SYNTHESIS OF POLYETHER-BLOCK-POLYAMIDES

The bulk reactions between 2,2'-bis (4,4-dimethyl-5 (4H) -oxazolone) (B3) or 2,2'-(1,2-ethylene)-bis(4,4-dimethyl-5(4H)-oxazolone) (B4) and amine-terminated polyether (Jeffamine ED-900) have been studied by SEC, and H-1- and C-13-NMR and the resulting polymers were characterized by DSC and TGA. These chain coupling reactions have been applied to the synthesis of polyether-block-polyamides, starting from mixtures of amine-terminated polyether and polyamide- 12. High molar mass block copolymers were synthesized in the bulk within 1 h at 200-degrees-C and under atmospheric pressure, instead of several hours at 240-degrees-C under vacuum for the usual reaction between dicarboxy polyamides and dihydroxy polyethers. No other side reactions than the formation of a very small amount of 2-imidazolin-5-ones has been found. The DSC studies of block copolymers show the existence of a phase separation between the soft (polyether) and hard (polyamide) blocks.