Abstract: High molecular weight poly L-alanine(PL-ALa) was prepared by thermal ring-opening polymerization of L-alanine-N-carboxyl anhydride. The influence of solvent, reaction temperature and monomer concentration on the polymerzation rate and the molecular weight of PL-Ala has been studied. It was found that the rate of polymerization and the molecular weight of PL-Ala have a maximum value at about 70℃ in different reaction systems.

Key words: N-carboxy-L-alanine anhydride, thermal ring-opening polymerization, polylalanine