COMPOSITE MATERIAL MADE OF REGENERATED SILK FIBROIN AND SILICA SOL

Regenerated silk fibroin solution and silica sol were mixed to produce the silk fibroin/silica composite materials. In order to probe if there is interaction between silk protein and silica, and further more, whether the interaction can improve the mechanical properties of composite materials, the structure and properties of the silk fibroin/silica composite material were studied by dynamic mechanical analysis (DMA) together with scanning electron microscopy (SEM) and Raman spectroscopy. The SEM results revealed the good compatibility between silk fibroin and silica in the composite. Nano-sized silica particles dispersed evenly in the continuous matrices of silk fibroin. Raman spectra of the composite materials indicated that the silk fibroin was dominated by P-sheet conformation. Comparing to the pure silk fibroin material, the composites showed better dynamic mechanical proper-ties in the range of 15 degrees C to 55 degrees C When the content of silica reached 10% the composite material appeared absolutely no dissipation in the temperature range around 40 degrees C. Due to both the hydrogen bond and electrostatic interaction between SiO2 and silk fibroin,the silica particles' interfusion among the chains of protein had a motive-impeding influence on the protein chains. This influence together with the stable P-sheet conformation of silk fibroin matrices led the avoidance of modulus dissipation of the material.