Synthesis of degradable porous polymers by ring-opening addition of a tri-aziridine and thiol-carboxylic acids

Ring-opening addition reaction between a tri-aziridine, pentaerythriyol-tris[3-(1-aziridinyl)propionate] (AZOH) or 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate] (AZ), and a thiol-carboxylic acid, thioglycolic acid (TGA) or thiolactic acid (TLA) or 3-mercaptopropionic acid (MPA), at room temperature in ethyl acetate produced porous polymers. The polymer networks were formed by the ring-opening reactions between the aziridine group of the tri-aziridine compounds with both the carboxylic acid and thiol groups of the thiol-carboxylic acids. The morphology of the porous polymers was composed by connected particles, whose averaged diameters ranged from about 2.5 to 7.5 µm. The reaction of AZOH and MPA under a high monomer concentration (40 wt%) yielded the porous polymer with co-continuous monolithic structure, whose backbone was formed by connected small particles of diameters of less than 0.2 µm. The porous polymers formed with TLA showed higher Young’s modulus due to small particle size and high density. The porous polymers showed good thermal stability. All porous polymers were decomposed in methanol within 50 days at room temperature.