Hyperbranched poly(ether amide)s via nucleophilic ring opening reaction ofoxazolines

The nucleophilic ring opening addition reaction of phenol groups towards ox azoline units has been used for the preparation of hyperbranched poly(ether amide)s. For this the AB:! monomer 2-(3,5-bishydroxyphenyl)-1,3-oxazoline was synthesized and converted in a highly branched polymer in bulk or solut ion at temperatures above 190 degreesC. The resulting hyperbranched polymer s exhibit a degree of branching of 50%, as verified by high-resolution NMR spectroscopy, and are highly soluble in polar organic solvents, for example DMF and DMAc, with low solution viscosity. Their glass transition temperat ures are in the region of 170 degreesC and degradation does not start below 300 degreesC. Melt rheology measurements revealed a predominantly elastic behaviour with a relatively high viscosity at low frequency. A lower melt v iscosity was achieved by end group modification. Hyperbranched poly(ether a mide)s with phenolic and acetate end groups are fully miscible with linear polyamide. When a small amount of the hyperbranched material is added to th e PA6 matrix a significant reduction of the melt viscosity could be achieve d without changing the mechanical properties of the matrix polymer.