Study of bulk chain coupling reactions. II. 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 1H‐and 13C‐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 amineterminated polyether and polyamide‐12. High molar mass block copolymers were synthesized in the bulk within 1 h at 200°C and under atmospheric pressure, instead of several hours at 240°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.