Aggregation structure characterization of silk fibroin–crosslinking oxidized bamboo pulp fibers

Bamboo pulp fiber as one of new promising green fiber was widely used in clothing, medical, automotive, construction, transportation, and many other areas. However, bamboo pulp fiber also has many defects such as larger shrinkage, lower wet strength, fabric wrinkle, and the poor ability to keep type. In this study, a green modification method for bamboo fiber was applied to overcome above-mentioned drawback and verified by scanning electron microscopy, Fourier-transform infrared spectrometry, X-ray diffraction, and solid-state CP/MAS 13C nuclear magnetic resonance respectively. The scanning electron microscopy results showed that oxidation treatment can cause fibers edge damage and denudation after modification, but can introduce the carboxyl groups to C-6 position of pure bamboo cellulose macromolecular. The X-ray diffraction results revealed that the fibers' crystalline structure was not changed throughout the modification process. The oxidation treatment processes can be interpreted as following: amino groups of silk fibroin first react with the carboxyl group and are connected to the fibers though C-N covalent bond, and then a smooth silk fibroin film was formed on the surface of fibers by crosslinking reaction of itself.