Synthesis and Antibacterial Activities of Quaternary Ammonium Salt of Gelatin

Cationic proteins with tunable chemical and physical properties were prepared from 2,3-epoxypropyl trimethyl ammonium chloride (EPTAC) and gelatin. Measurement of grafting density indicated that the molar ratio of EPTAC/amine groups (NH₂) in the gelatin chains played a key role in determining the compound's structure. Fourier transform infrared (FTIR) and ¹³C NMR results showed that the –NH₂ functional groups of gelatin were totally consumed when the molar ratio of EPTAC/NH₂ was increased to 2.5:1. Hydroxyl (?OH) functional groups of gelatin were also depleted upon further increasing the molar ratio of EPTAC/NH₂. Antibacterial activity and thermal properties of the product polymers changed with the modification of the polymers’ structure.