N-ALLYLATED AROMATIC POLYAMIDES

Poor processability of poly(p-phenyleneterephthalamide) (PPTA) has been a limiting factor for the wider use of this polymer. One approach to improve its processability is to modify the polymer into an N-alkylated or N-arylated tertiary polyamide form. The validity of this approach was studied. A PPTA anion solution was prepared in DMSO with various bases, such as sodium dimsyl, potassium tert-butoxide, sodium amide, and lithium dialkylamides. The anion reacts with allyl bromide to give a near quantitative conversion to N-allylated PPTA. This polymer shows no crystallinity and a high solubility in chlorinated solvents. Other N-allylated aramids, such as poly(m-phenyleneisophthalamide) (PMIA) and poly(4,4'-biphenyleneisophthalamide) (PPBA), also show totally different properties from the parent polymers. The X-ray structure of N1,N4-bisallylated N1,N4-dibenzoyl(1,4-phenylenediamine) reveals that the torsion angle between two adjacent aromatic rings is much higher than that of the parent secondary amide. This structure suggests that N-allylated PPTA should have a random-coil structure.