Synthesis and characterization of poly(copolyethers- block-polyamides) II. Characterization and properties of the multiblock copolymers

Abstract

Multiblock copolymers were synthesized from an α,ω-dicarboxy-oligododecanamide (PA12dC; M ̄ n =2095) and various α,ω-dihydroxy-polyethers ( M ̄ n =1000–2000), especially, as copolyethers containing both polyoxyethylene and polyoxypropylene blocks. The polycondensation reaction was carried out in bulk at high temperature in the presence of Zr(OBu) 4 as catalyst. A kinetic study permitted one to compare the reactivity of the different oligoethers used with respect to PA12dC. The thermal properties, the structure and morphology of these poly(polyethers- block-polyamides) were characterized by DSC, TGA, DMA and solid-state 13C NMR. DSC and DMA results show that the multiblock copolymers based on copolyethers exhibit a very high degree of phase separation and these soft blocks do not crystallize, whatever their length and composition. NMR results reveal that the crystalline polyamide phase adopts a structure (γ-form) similar to that of the oligoamide precursor.