Um I C, Kweon H Y, Park Y H, Hudson S
Department of Natural Fiber Sciences, College of Agriculture and Life Sciences, Seoul National University, Suwon 441-744, South Korea.
Int J Biol Macromol. 2001 Aug 20;29(2):91-7. doi: 10.1016/s0141-8130(01)00159-3.
Structural characteristics and thermal and solution properties of the regenerated silk fibroin (SF) prepared from formic acid (FU) were compared with those of SF from water (AU). According to the turbidity and shear viscosity measurement, SF formic acid solution was stable and transparent, no molecular aggregations occurred. The sample FU exhibited the beta-sheet structure, while AU random coil conformation using Fourier transform infrared (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry. The effects of methanol treatment on samples were also examined. According to the measurement of crystallinity (XRD) and crystallinity index (FTIR), the concept of long/short-range ordered structure formation was proposed. Long-range ordered crystallites are predominantly formed for methanol treated SF film while SF film cast from formic acid favors the formation of short-range ordered structure. The relaxation temperatures of SF films measured by dynamic thermomechanical analysis supported the above mechanism due to the sensitivity of relaxation temperature on the short-range order.
将由甲酸（FU）制备的再生丝素蛋白（SF）的结构特征、热性能和溶液性质与水相（AU）的SF进行了比较。根据浊度和剪切粘度测量，SF甲酸溶液稳定且透明，未发生分子聚集。利用傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）和差示扫描量热法，样品FU呈现β-折叠结构，而AU为无规卷曲构象。还研究了甲醇处理对样品的影响。根据结晶度（XRD）和结晶度指数（FTIR）的测量，提出了长/短程有序结构形成的概念。甲醇处理的SF膜主要形成长程有序微晶，而由甲酸浇铸的SF膜有利于形成短程有序结构。动态热机械分析测得的SF膜松弛温度支持上述机制，因为松弛温度对短程有序敏感。
