Zhang Xin, Pan Zhijuan
College of Textile and Clothing Engineering, Soochow University, Suzhou 215021, China.
National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123, China.
Polymers (Basel). 2019 Oct 8;11(10):1622. doi: 10.3390/polym11101622.
With excellent biocompatibility and biodegradability, silk fibroin has been developed into many protein materials. For producing regenerated silk fibroin (RSF) fibers, the conformation transition of silk fibroin needs to be thoroughly studied during the spinning process. Since the many silk fabrics that are discarded comprise an increasing waste of resources and increase the pressure on the environment, in this paper, waste silk fiber was recycled in an attempt to prepare regenerated fibroin fiber by dry-wet spinning. Ethanol was the coagulation bath. The rheological properties of all the RSF solutions were investigated to acquire rheology curves and non-Newtonian indexes for spinnability analysis. Four stages of the spinning process were carried out to obtain RSF samples and study their conformation transitions, crystallization, and thermal properties by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, and differential scanning calorimetry. Quantitative analysis of the FTIR results was performed to obtain specific data regarding the contents of the secondary structures. The results showed that higher concentration spinning solutions had better spinnability. As the spinning process progressed, random coils were gradually converted into β-sheets and crystallization increased. Among the different influencing factors, the ethanol coagulation bath played a leading role in the conformation transitions of silk fibroin.
由于具有出色的生物相容性和生物降解性，丝素蛋白已被开发成多种蛋白质材料。在生产再生丝素蛋白（RSF）纤维时，需要在纺丝过程中深入研究丝素蛋白的构象转变。鉴于大量被丢弃的丝绸织物造成了日益严重的资源浪费并增加了环境压力，本文尝试通过干湿法纺丝回收废丝纤维来制备再生丝素蛋白纤维。以乙醇作为凝固浴。研究了所有RSF溶液的流变特性，以获得流变曲线和非牛顿指数用于可纺性分析。进行了纺丝过程的四个阶段以获得RSF样品，并通过傅里叶变换红外光谱（FTIR）、X射线衍射和差示扫描量热法研究它们的构象转变、结晶和热性能。对FTIR结果进行了定量分析以获得有关二级结构含量的具体数据。结果表明，较高浓度的纺丝溶液具有更好的可纺性。随着纺丝过程的进行，无规卷曲逐渐转变为β-折叠且结晶增加。在不同的影响因素中，乙醇凝固浴在丝素蛋白的构象转变中起主导作用。
