Homogeneous alkylation of poly(m-phenylene isophthalamide)

Homogeneous alkylation of poly(m‐phenylene isophthalamide) (PMIA) was carried out in N‐methyl‐2‐pyrrolidone. Alkyl halides such as benzyl bromide and allyl bromide were reacted with sodium‐metallated PMIA. When the Taft equation was applied to this substitution reaction, the linear relationship was apparently obtained between log k/k0 and σ*. The molecular weight of alkylated PMIA decreased by sodium‐metallation and alkylation reactions. The weight loss of PMIA derivatives on heating increased with an increasing degree of substitution of the benzyl group, but it was improved by the reaction of the unsaturated alkyl group with 1,2‐ethanedithiol.