The PEG-b-PAsp-g-PBE copolymer was synthesized via the amine-initiated ring-opening polymerization (ROP) and esterification reaction. With different molar ratio between BLA-NCA and m-PEG-NH2, we obtained different block copolymers with different molecular weight. According to the length of PAsp chain, PBE with proper molar ratio was added into reaction solution and we get PEG-b-PAsp-g-PBE with different grafting degree (Yang et al., 2015 (link); Hu et al., 2017 (link); Wang et al., 2020 (link)). 1H NMR spectra of the polymers were recorded on a Bruker 400 MHz nuclear magnetic resonance instrument using D2O as the solvents. Gel permeation chromatography (GPC) was used to analyze the molecular weights and molecular weight distributions (Mw/Mn) of the polymers. GPC of polymer (PEG-b-PAsp and PEG-b-PAsp-g-PBE) was measured by a Waters 1525 chromatograph equipped with a Waters 2414 refractive index detector.