Abstract:Free thiol groups are easily connected to form disulfide bonds, which will adversely affect the stability of keratin solution and the properties of regenerated keratin. Therefore, proper protection of thiol groups can help improve the performance of keratin. In this paper, polyethylene glycol (PEG), polyvinyl alcohol (PVA) and sodium dodecyl sulfate (SDS) was employed as the main compounds and their protective effects on thiol groups was detailed studied. Then, PEG with the best protection effect was chosen as the main study object. The influence of PEG molecular weight and concentration on the protection effect of sulfhydryl groups was further analyzed. The micelle particle size, hydrophobic amino acid exposure ratio, and the secondary conformation were also characterized by using DLS, Fluorescence spectroscopy, and Raman spectroscopy. The results showed that PEG can form polymer complexes with keratin molecules through hydrophobic interaction, hydrogen bonding. Moreover, the Ker/PEG complex made the keratin molecules stretch and weaken the disordered cross-linking of thiol groups. Compared with the keratin film, the secondary structure of PEG/Ker became much more regular, and the flexibility and light transmittance of the membrane was also significantly increased.