The phosphazene polymers carrying phenoxycarboxylic acids {[NP(O-C6H4-CO2H)(2)](x)[NP-(O2C12H8)](1-x)}n [x = 0.2 (1a), 0.35 (1b), 0.5 (1c), 0.7 (1d), 0.85 (1e), x = 1(2)] and the chiral analogues {[NP(O-C6H4-CO2H)(2)](x)[NP(O2C20H12)](1-x)}n [x = 0.2 (3a), 0.45 (3b), 0.7 (3c)] (O2C12H8 = 2,2 '-dioxybiphenyl, O2C20H12 = R-2,2 ' dioxy-1,1 '-binaphthyl) have been synthesized by hydrolysis of the corresponding precursors with [NP(O-C6H4-CO2Pr)(2)] units. The new polymers have extensive H-bonding between the -COOH groups in the solid state, and those with x > 0.5 are very soluble in aqueous 0.5 M sodium carbonate. These polymers were used as initiators of the ring-opening polymerization of the E-caprolactam (c-CL) at 230 degrees C to give un-cross-linked polyphosphazenes, branched with short polyamide chains but having a fraction of the phosphazene units (from 20 to 35%) modified by secondary reactions.