Sequence-Controlled Synthesis of Alternating Poly(ester amide)s using Water as Control Agent in One-Pot

Abstract

Poly(ester amide)s (PEAs) attract much attention as a new kind of biodegradable polymers. However, the synthesis of PEAs with sequence-regulated chain structures is still complicated due to the multistep polymerization, high monomer purity, as well as the usage of organic solvents, which greatly inhibits its development and applications. Herein, a one-pot strategy without solvent was developed to synthesize the alternating PEA from α,ω-amino alcohol and dicarboxylic acid by sequential polycondensation, where water was used as the controlling agent for amidation and esterification. Specifically, the amidation and esterification were controlled to proceed in turn by adding or removing water, realizing the one-pot preparation of alternating PEAs. The resultant PEA is characterized by ¹H- and ¹³C-NMR, and its chain structure is confirmed to be highly quasi-alternating similar to alternating PEAs prepared by classical methods The evaluations from DSC and DMA demonstrate that the properties of quasi-alternating PEA (T_m=102 °C, ΔH_m=30 J·g⁻¹) are far superior to those of random PEA (T_m=72 °C, ΔH_m<1 J·g⁻¹).