Abstract:

Objective River mud is crucial for the formation of the coating on the gummed Canton silk. However, there is still a lack of understanding of the organic components in the river mud. In order to understand the key organic components and structural characteristics of the river mud used in the production of gummed Canton silk, and to clarify the difference between the river mud used in gummed Canton silk and ordinary river mud, an investigation on river muds was carried out.
Method River mud was collected from Shunde and Xiqiao, and locally from Hangzhou, which were then separated and purified. Using Hangzhou local mud as the control, river mad components characterized the obtained were characterized and obtained with the use of ultraviolet-visible (UV-vis) spectra, infrared spectra and X-ray photoelectron spectroscopy (XPS), and compared the similarities and differences between them.
Results The UV-vis spectra (Fig. 2) shows that 200-220 nm belongs to the E2 band absorption of the benzene ring, and 240-270 nm belongs to the B band absorption of the benzene ring. In addition, the oxygen containing functional group content index A₂₅₃/A₂₀₃ and humus aromaticity index values of river mud of gummed Canton silk were higher than those of local river mud. Infrared spectra (Fig. 3), indicates that the attached components of the fabric surface coating showed obvious spectral characteristics of humic acid and fulvic acid components. The unattached component demonstrated the spectral characteristics of the humic component. XPS full scan spectra (Fig. 5 and Tab. 2) suggests that humic acid and fulvic acid contained inorganic elements such as silicon and chlorine in addition to carbon, oxygen and nitrogen. After several times of alkali dissolution and acid precipitation, there was still some iron in the humic acid component of the river mud used for gummed Canton silk, while there was no iron in the humic acid component of local river mud. According to fitting results of carbon element peaks (Fig. 6 and Tab. 3), humic acid and fulvic acid in river mud used for gummed Canton silk contain higher aromatic carbon content and the proportion of C—O/C—OH/C—N, C=O, C(O)N, C(O)O four chemical forms.
Conclusion It was determined that humic acid and fulvic acid in the organic matter of river mud participated in the construction of the coating on the gummed Canton silk, while humin did not participate in the reaction. Compared with the local Hangzhou river mud, there are great differences in the structure and properties of humic acid and fulvic acid components in the river mud of gummed Canton silk production area. First of all, its humic acid and fulvic acid are more aromatic. Secondly, there are significant differences in the content of various functional groups, especially fulvic acid, which has higher hydroxyl, carboxyl, peptide bond and other oxygen-containing functional groups on the molecular structure of fulvic acid in river mud. Finally, its humic acid component has stronger iron ion binding capacity. The high aromatic degree of humic acid and fulvic acid in the river mud used in the production of gummed Canton silk makes the coating of gummed Canton silk more black and bright. Its high oxygen functional group content and strong iron ion complexing ability enable river mud humic acid and fulvic acid to form a stable complexing structure with dioscorea cirrhosa pigment and silk, thus forming a solid coating.

Key words: gummed Canton silk, coating, river mud, humic substance, structure characteristic