Synthesis And Degradation Differences Of Chiral Polyamideimides Based On Amino Acids And Their Derivatives

Biodegradable polymers are rapidly developing and have broad applications prospects in food packaging,tissue engineering,and biomedical applications.Amino acids are the simplest chiral biomolecules containing intramolecular hydrogen bonds that serve as building blocks for more complex peptides and proteins.Amino acid based polymers exhibit similar biocompatibility and biodegradability to peptides and proteins.Amino acid-based polyamideimides(PAIs)are excellent in heat resistance,processability,and improved degradation properties and higher biocompatibility due to the introduction of natural chiral moieties.In this paper,four different diacids monomer containing imides groups were prepared by selecting different amino acids as chiral sources.Then,six diacid monomers having a dipeptide structure were synthesized by using carbodiimide as condensing agent.The structures of these compounds were characterized by FT-IR,1H-NMR and elemental analysis.It was confirmed that the obtained compounds were being high purity.The synthesized diacid monomers are then reacted with ODA to synthesize a series of homopolymerized PAIs and randomly copolymerized PAIs.The synthesized polymers were also characterized by FT-IR,1H-NMR and elemental analysis,respectively,which proved that the obtained materials conformed to the expected structure and had high purity.The results of DSC and TGA indicate that these polymers based on amino acid and dipeptide structures have good thermal properties.The thermal properties of PAIs containing the L configuration may be better than those of the PAIs containing the D configuration.The PAIs which having two different configurations of the L-configuration and the D-configuration have lower PAIs.There is a lower Tg value when the pendant group of the polymer contains a large pendant benzene ring group.This indicates that the configuration and structure of the amino acids together affect the Tg value of the polymers.Finally,the enzymatic degradation experiments showed that the microorganism preferentially degraded the polyamideimides(PAIs)containing the L-configuration.This enantioselectivity may result from the interaction of spin polarization.This mechanism of interaction between chiral molecules leads to a higher efficiency of degradation of PAIs in the L-configuration.PAIs containing peptide bonds have better degradability than PAIs containing only amide bonds.When the amino acid structure of PAIs is introduced,the structure also has a significant effect on the degradation effect.Degradation of PAIs containing natural chiral amino acids is superior to that containing non-natural chiral amino acids.