Homo and Block Copolymers of Poly( β ‐benzyl‐ L ‐aspartate)s and Poly( γ ‐benzyl‐ L ‐glutamate)s of Different Architectures

Homopolypeptides of linear and star‐like architectures were prepared by polymerizing benzylic‐protected L ‐glutamic acid and L ‐aspartic acid N ‐carboxyanhydrides (Glu NCA, Asp NCA) in DMF. The polymerization rate of the Glu NCA is faster than that of Asp NCA. Using a simple monoamino initiator, its hydrochloride, di‐, tri‐, and tetraamino functional initiators, homopolypeptides with well‐defined structures and molar masses were obtained. The molar‐mass averages of the poly( γ ‐benzyl‐ L ‐glutamate)s lie very close to calculated values, according to the initial [M]:[I] ratios, while those of the linear poly( β ‐benzyl‐ L ‐aspartate)s were lower than the predicted ones. PBAs had somewhat broader molar‐mass distributions than PBGs.