Modified Gelatin With Quaternary Ammonium Salts Containing Epoxide Group

Quaternary ammonium salts containing epoxide group-type of cationic surfactantsare composed of a hydropHilic epoxy quaternary ammonium head group and ahydropHobic tail group. The special property of quaternary ammonium salts containingepoxide group is the reactivity due to the epoxide group. It can be used as an importantintermediate for organic synthesis to introduce quaternary ammonium group into thenatural macromolecules (e.g. gelatin), which improves the properties ofself-emulsifying and antibacterial of the natural materials. Collagen peptide is widelyused in many fields as it has excellent biological compatibility and biodegradability butits poor mechanical properties and antibacterial activity limit its use in the moredemanding fields. Chemical grafting or cross-linking of gelatin is an effective way tointroduce stable covalent bonds between protein segments to obtain a modified productwhich provides greater control of chemical and pHysical properties compared to naturalpolymers.Epoxypropyl dodecyl dimethyl ammonium chloride was synthesized with N,N-dimethyl dodecyl amine and epichlorohydrin（methanol as solvent, T=45℃, t=2h, theconversion rate was77.27%, the epoxy value was44.97%）Diethyl-2,3-epoxypropyl-[3-methyldimethoxyl)] silpropyl ammonium chloride wassynthesized with N, N-dimethyl dodecyl amine, epichlorohydrin (NAPMDMS),γ-chloropropylmethyldimethoxysilane and diethylamine（methanol as solvent, T=55℃,t=8h, the conversion rate was86.16%, the epoxy value was70.34%）. The productswere characterized by IR, Elemental analysis and1H NMR spectroscopy. A series ofthermodynamical properties and surface properties were investigated. This typesurfactants have the well-known properties of cationic surfactants of forming micellesin aqueous solutions and showing remarkable surface-active properties, such as lowercritical micelle concentration (CMC) values and lower surface tension at the CMC.EPDDMAC-GE was prepared from Epoxypropyl dodecyl dimethyl ammoniumchloride (EPDDMAC) and gelatin (the molar ratio of EPTAC/NH2was1:1, gelatinsolution8%ws/wg, T=50℃, t=5h, pH=10, the conversion of-NH2groups was40.03%).DEEPSAC-GE was prepared from Diethyl-2,3-epoxypropyl-[3-methyldimethoxyl)]silpropyl ammonium chloride (DEEPSAC) and gelatin (the molar ratio of EPTAC/NH2was1:1, gelatin solution6%ws/wg, T=55℃, t=5h, pH=11, the conversion of-NH2 groups was42.15%). The gelatin-modified polymers exhibit excellent antibacterialproperties.