The preparation of acid chloride of poly(propylene oxide), PPO, the synthesis of prepolymer poly(p-benzamide), and of block copolymers of poly(p-benzamide)-b-poly(propylene oxide) are reported. The preparation of prepolymer poly(p-benzamide), PBA, and activated PPO, as well as PBA-PPO block copolymer are discussed according to their FTIR spectra.