Synthesis And Properties Of Modified Gelatin Hydrolysate With Polysiloxane Quaternary Ammonium Salts Containing Epoxy Groups

Polysiloxane quaternary ammonium salt containing epoxy group (P(SiO)m(SiOQAEp)n) cationic surfactants are composed of a hydrophilic epoxy quaternary ammonium head group and a polysiloxane chain hydrophobic tail group. The special property of quaternary ammonium salts containing epoxide group is the reactivity due to the epoxide group. It can be used as an important intermediate for organic synthesis to introduce quaternary ammonium group into the natural macromolecules (e.g. gelatin), which improves the properties of self-emulsifying and antibacterial of the natural materials. Collagen peptide is widely used in many fields as it has excellent biological compatibility and biodegradability but its poor mechanical properties and antibacterial activity limit its use in the more demanding fields. To widen its field of application, gelatin was firstly hydrolyzed and then chemically modified with inorganic compounds which are introduced to graft to the gelatin hydrolysate (GH). It can be used as an effective way to introduce stable covalent bonds among protein segments to improve the chemical and physical properties of natural polymers.Four P(SiO)m(SiOQAEp)n with different molecular weights have been successfully synthesized.In the quaternization process, with the molar ratio of P(SiO)m(SiOTA)n and epichlorohydrin was 1:1.3 and methanol as solvent, the conversion rate was 93.26%. The products were characterized by IR and lH NMR spectroscopy. A series of thermodynamical properties and surface properties were investigated. This type surfactants have the well-known properties of cationic surfactants of forming micelles in aqueous solutions and showing remarkable surface-active properties, such as lower critical micelle concentration (CMC) values and lower surface tension at the CMC.Pn-GH was prepared from Polysiloxane quaternary ammonium salt containing epoxy group (P(SiO)m(SiOQAEp)n) and gelatin hydrolysate (the molar ratio of epoxy group/NH2 was 1:1, gelatin solution 10% ws/wg, T=50℃, t=6h, pH=10, the conversion of-NH2 groups was 40.03%). The structure of modified gelatin is characterized by FT-IR and’H-NMR. The glass-transition temperatures Tg, contact angles and antibacterial properties are reported. Compared with initial gelatin hydrolysate, the gelatin hydrolysate which was modified with quaternary ammonium salts containing epoxy groups exhibits stronger antibacterial activities, hydrophobic properties and thermal stability properties.