Synthesis And Properties Of Temperature-sensitive Polyester Based On Passerini Reaction

As one of the typical representative of multi-component reactions,Passerini reaction refers to the chemical process of producing organic molecules containing ester and amide bonds with carboxylic acids,aldehydes and isocyanides as raw materials.Passerini reaction has the advantages such as mild reaction conditions,little environmental pollution,simple and efficient polymerization operation,atomic economy and no by-products formation.In recent years,the application of Passerini multi-component reaction in polymer preparation has attracted much attention from scholars.In this study,the Passerini reaction was applied to the design and preparation of thermosensitive polyesters,and the application of thermosensitive polyesters in drug carriers was preliminarily studied.1.The current research advances of Passerini reaction in polymer chemistry is briefly introduced,including the synthesis of monomers,sequence regulation of polymers,the preparation of dendrimers and the modification of polymers.2.In this study,a series of polyesters were successfully prepared by using five dicarboxylic acids,dialdehyde and t-butyl isocyanide as monomers by Passerini reaction via "one pot" method.The effects of monomer feed ratio,monomer concentration,solvent,temperature,reaction time and different dicarboxylic acids on the polymerization were investigated.The gradual polymerization nature was verified and the optimal polymerization conditions were also obtained.3.Several kinds of succinic anhydride-terminated polyethylene glycol(PEG-B)with different molecular weight were firstly synthesized.In homogeneous polymerization,using PEG-B with molecular weight of 400,800,1000,2000 and 4000 as monomers,the resulting polyester shows excellent thermo-sensitivity,and the lower critical solution temperature(LCST)is in the range of 28.5-84.2℃.Through the copolymerization of PEG-B with molecular weight 400 and 800,the LCSTs for polyester can be conveniently controlled to 38.7,42.3 and 58.0℃,respectively.The results of HeLa cytotoxicity test based on MTT method indicated that after 24-72 hours of incubation,the viability rate of HeLa cells reached to 80%,or even surpassed 100%,showing excellent biocompatibility of polyester.4.In addition,the polyester with S-S bonds on the main chain was successfully prepared by Passerini polymerization with 3,3’-dithiodipropionic acid as a new monomer.With the aid of the hydrophobicity of curcumin(Cur)and the polyester,the particle with the size of 200-400 nanometers and homogeneous core-shell structure was obtained by dialysis method.The preliminary results indicated that the effective control release of curcumin from drug-loaded carriers was achieved by the characteristic reaction of chain breaking agent,tris(2-carboxyethyl)phosphine(TCEP)with S-S bond.In conclusion,Passerini polymerization has provided a convenient and efficient technique for the preparation and the performance control of polyesters containing different functional groups.