关键词: 真丝织物, 串联反应, 协同增效, 抗菌性能, 染色性能

Abstract: With excellent wearability, biocompatibility and biodegradability, silk is widely used in textile, biomedicine, food and other fields. Chemical modification is an important technical means to further expand the use of silk. However, the protein properties of silk have high requirements on chemical raw materials and reaction paths, so it is difficult for traditional single substance modification methods to achieve green and efficient modification at the same time. In this paper, a new method of tandem chemical modification of real silk fabric (SF) using water-soluble carboxylated chitosan (CMC) and 2,3-epoxy-propyl trimethyl ammonium chloride (GTA) is proposed for the first time. The morphology, structure and physicochemical properties of SF, SF/CMC, SF/GTA and SF/CMC/GTA samples were compared and analyzed by means of scanning electron microscopy, fourier transform infrared, X-ray diffraction, X-ray photoelectron spectroscopy, tensile test and thermogravimetric analysis. The results show that although the amide bond formed by CMC reaction in infrared spectroscopy coincides with SF characteristic peak, the shift of carbonyl C binding energy and the increase of C-N peak area in X-ray photoelectron spectroscopy prove that the tandem chemical modification can be successfully implemented at 80 ℃ in aqueous solvent. The introduction of CMC provides more reaction sites for GTA, and a large number of hydroxyl groups forming after the reaction of GTA can form rich hydrogen bonds with CMC to help it stabilize. With the chemical modification in tandem, a small amount of fiber appeared on the surface of the fabric fiber. X-ray diffraction spectra also showed that the modification reaction was mainly in the amorphous region of the surface, and had little effect on the SF crystal structure. Compared with SF, the tensile strength (62.7 MPa) and thermal decomposition temperature (327 ℃) of SF/CMC/GTA have no obvious changes, which shows that the series modification method used in this work is mild and effective, and the modified fabric still maintains good mechanical properties and thermal stability. The difference is that compared with SF, the permeability and water absorption of SF/CMC/GTA increased significantly, reaching 272 g·m-2·d-1 and 326%, respectively, which should be related to the strong hydrophilic groups introduced by CMC and GTA. In addition, the Zeta potential of SF/CMC/GTA (1.5 mV) was significantly increased compared with that of SF (-26.3 mV), proving the high efficiency of tandem modification. Compared with the single modified sample SF/CMC and SF/GTA, the tandem-modified sample SF/CMC/GTA had a quite high antibacterial rate (above 99.9%) both against S. aureus and E. coli. The dyeing experiment showed that the dyeing rate of SF/CMC/GTA was 55 times higher than that of SF, which is expected to be applied in the field of non-washing printing and dyeing. This paper provides scientific data for the application of tandem reaction in functional modification of real silk fabrics and a new technical path for green silk dyeing and finishing.

Key words: silk fabric, tandem reaction, synergistic effect, antibacterial property, dyeing property