Synthesis of a novel block copolymer containing aromatic polyamide and fluoroethylene segments

Synthesis of Block Copolymers containing Chain‐Controlled Aramid and Fluoroethylene Segments

“…Although the aramid which consists of 3,4′‐DAPE and IPC is dissolved in polar solvents, such as DMAc and DMF, but not in acetone and tetrahydrofuran (THF),3,18 our block copolymers were actually dissolved or swelled in acetone and THF. This solubility of our block copolymers in the solvents is similar to that of the fluorine‐containing aromatic polyamides reported in previous studies, because the fluorine atom has weak intermolecular cohesive energy,5,19 This result proves that incorporating fluoroethylene segments improves the solubility of the resulting polymer, as described in our former paper 9…”

“…The number‐average molecular weight ($\overline M _{\rm n}$ ) of 2a is 20 300. This molecular weight is larger than that of the polymer reported in our previous paper,9 because of the effect of the size of the monomers. On the other hand, there is a tendency to the effect that the larger the molecular weight of the monomers (which are the constituents of the polymers), the smaller the molecular weight of the polymers obtained from this reaction system.…”

“…The peak of the amide bond adjacent to the fluorocarbon group shifts to the low magnetic field side compared to that in the aramid segment 17. This is due to the presence of CF 2 , described in our former report 9. The proton of the amide bond neighbor to CF 2 is deshielded 16.…”

“…Although these polymers were soluble in polar solvents, such as N , N ‐dimethylformamide, N , N ‐dimethylacetamide, and dimethyl sulfoxide, solubility in regard to other solvents was not clarified. In an earlier publication, we demonstrated the synthesis of fluoroethylene‐aramid block copolymer soluble in tetrahydrofuran and acetone, and not just in polar solvents 9. The number‐average molecular weight of this copolymer, however, is 1.7 × 10 4 .…”

Synthesis, characterization, and water sorption properties of new aromatic polyamides containing benzimidazole and ethylene oxide moieties

“…It is well known that processability may be improved by the addition of flexible chains to the polyamide backbone, which enhance the molecular mobility, providing better solubility and reducing T g 8–11. For this particular purpose, ethylene oxide units have been extensively incorporated into polymers 12–15.…”