A. Boulares et al., Synthesis and characterization of poly(copolyethers-block-polyamides) II. Characterization and properties of the multiblock copolymers, POLYMER, 41(10), 2000, pp. 3561-3580
Multiblock copolymers were synthesized from an alpha,w-dicarboxy-oligododec
anamide (PA12dC; (M) over bar(n) = 2095) and various alpha,w-dihydroxypolye
thers ((M) over bar(n) = 1000-2000), especially, as copolyethers containing
both polyoxyethylene and polyoxypropylene blocks. The polycondensation rea
ction 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 o
f the different oligoethers used with respect to PA12dC. The thermal proper
ties, the structure and morphology of these poly(polyethers-block-polyamide
s) were characterized by DSC, TGA, DMA and solid-state C-13 NMR. DSC and DM
A results show that the multiblock copolymers based on copolyethers exhibit
a very high degree of phase separation and these soft blocks do not crysta
llize, whatever their length and composition. NMR results reveal that the c
rystalline polyamide phase adopts a structure (gamma-form) similar to that
of the oligoamide precursor. (C) 2000 Elsevier Science Ltd. All rights rese
rved.