Polymers from Amino acids: Development of Dual Ester-Urethane Melt Condensation Approach and Mechanistic Aspects

Abstract

A new dual ester-urethane melt condensation methodology for biological monomers-amino acids was developed to synthesize new classes of thermoplastic polymers under eco-friendly and solvent-free polymerization approach. Naturally abundant L-amino acids were converted into dual functional ester-urethane monomers by tailor-made synthetic approach. Direct polycondensation of these amino acid monomers with commercial diols under melt condition produced high molecular weight poly(ester-urethane)s. The occurrence of the dual ester-urethane process and the structure of the new poly(ester-urethane)s were confirmed by (1)H and (13)C NMR. The new dual ester-urethane condensation approach was demonstrated for variety of amino acids: glycine, β-alanine, L-alanine, L-leucine, L-valine, and L-phenylalanine. MALDI-TOF-MS end group analysis confirmed that the amino acid monomers were thermally stable under the melt polymerization condition. The mechanism of melt process and the kinetics of the polycondensation were studied by model reactions and it was found that the amino acid monomer was very special in the sense that their ester and urethane functionality could be selectively reacted by polymerization temperature or catalyst. The new polymers were self-organized as β-sheet in aqueous or organic solvents and their thermal properties such as glass transition temperature and crystallinity could be readily varied using different l-amino acid monomers or diols in the feed. Thus, the current investigation opens up new platform of research activates for making thermally stable and renewable engineering thermoplastics from natural resource amino acids.

Melt polycondensation approach for reduction degradable helical polyester based on l‐cystine

“…Earlier, we have reported dual ester-urethane condensation approach for L-amino acid based linear poly(ester-urethane)s, hyperbranched poly(ester-urethane)s, and functional polyesters. [42][43][44][45] Based on this experience, in the present investigation, melt polycondensation is successfully developed for multi-functional L-cystine monomer to make new disulfide containing polyesters (see Fig. 1).…”

Enzyme and pH dual responsive l -amino acid based biodegradable polymer nanocarrier for multidrug delivery to cancer cells

“…). For this purpose, thermoselective melt polycondensation strategies earlier developed from our laboratory for l ‐amino acid resources were employed to make amphiphilic biodegradable polymer nanoassemblies. New classes of amphiphilic biodegradable polyester having side chain BOC urethane were designed from l ‐aspartic acid by thermoselective melt polymerization approach.…”

Precision synthesis of sustainable thermoplastic elastomers from lysine‐derived monomers

“…Amino acids are naturally available renewable resources, and recent advances in aerobic fermentation have made it possible to obtain amino‐acids with high purity and relatively low price. Therefore, extensive research has focused on the synthesis of biorenewable polymers based on amino‐acids monomers . We previously proposed a new chemical strategy based on ring‐opening polymerization (ROP) to obtain ε ‐poly‐lysine from lysine .…”

“…Therefore, extensive research has focused on the synthesis of biorenewable polymers based on amino-acids monomers. [15][16][17][18][19][20][21][22][23] We previously proposed a new chemical strategy based on ring-opening polymerization (ROP) to obtain e-poly-lysine from lysine. 15 Meanwhile, we have also been investigating controlled ROP of O-carboxyanhydride (OCA) monomer obtained from L -lysine to generate renewable lysine-based polyester.…”