The procedure used to synthesize multiblock (PIB-PA)n TPEs
(Scheme 1) is a modification of the Arkema two-prepolymer
method. Two different difunctional carboxyl-terminated PA hard
segments were investigated. A polyamide 6 (PA-6) prepolymer was
formed by ring-opening polymerization of ε-caprolactam, and a
polyamide 11 (PA-11) prepolymer was formed by step polymerization
of 11-aminoundecanoic acid. In both cases, adipic acid was
used to control molecular weight and produce carboxylic acid end
groups. In parallel, difunctional primary amine-terminated PIB
(NH2-PIB-NH2) was synthesized via cationic polymerization utilizing
in situ quenching and post-polymerization modification. In a
final step, carboxyl-terminated PA was reacted with primary