将合成的离子液体作为反应介质,以明胶作为皮胶原模拟物,分别加入改性剂引入和封闭明胶的氨基和羧基,并通过红外(FT-IR)、等电点(PI)、总碳含量(TOC)和热重分析(TG)等方法分别对修饰前后明胶的结构和性能进行了表征。结果显示,修饰后明胶的氨基和羧基含量发生了明显变化;氨基增加、封闭明胶和羧基增加、封闭明胶总碳含量分别提高了14.7%、20.5%和33.2%、9.6%;未改性明胶等电点为4.8,氨基增加和羧基封闭明胶的等电点分别上升到7.1和6.4,氨基封闭和羧基增加明胶的等电点分别下降为3.2和2.2;氨基增加、封闭明胶和羧基增加、封闭明胶5%的热失重温度由109.4℃分别变化到160.4℃、93.5℃和196.4℃、106.3℃,上述研究表明胶原的侧基在离子液体中易于被修饰。
[BMIM]C1 was prepared and used as a medium, gelatin was used as a model of collagen, (Boc)20, melamine, tri- ethyl orthoacetate and Maleie anhydride were used as modification agents, the amino and carboxyl groups of protein were blocked and introduced respectively. The differences in structure and properties of gelatin before and after modification were characterized with Fourier Transform Infrared (FT-IR), Zeta potential (PI), Total Organic Carbon (TOC) and Thermogravimet- ric (TO analysis. Results showed that 5% weight loss temperature changed from 109.4 ℃ to 160.4 ℃, 93.5 ℃ for the amino- added and amino-terminated samples and 196.4℃, 106.3℃ for carboxyl-added and earboxyl-terminated samples, respec- tively. Similarly, the Zeta potential changed from 4.8 to 7.1, 3.2 for the former and 6.4, 2.2 for the later, the Total Organic Car- bon (TOC) content increased by 14.7%, 20.5% for the former and 33.2%, 9.6% for the later, respectively, which reveals that the pendent groups of collagen (such as amino and carboxyl groups) are easily modified in ionic liquid.