Kinetics of polymerization of N‐carboxy amino acid anhydride in dimethyl sulfoxide

Various kinds of NCA's were polymerized in dimethyl sulfoxide (DMSO). DL‐Alanine NCA polymerized at a fast rate without initiator, the rate being represented by Rp1 = k[M]1/2. When the polymerization was carried out in chloroform in the presence of DMSO, the rate was represented by the equation, Rp2 = K2[M][DMSO]1/2. Glycine NCA and DL‐α‐amino‐n‐butyric acid NCA also polymerized at a fast rate in DMSO without initiator. On the other hand, N‐methylglycine NCA, DL‐ and L‐valine NCA and DL‐ and L‐leucine NCA did not polymerize in DMSO without initiator.