Effect of secondary vulcanization process on hydrophobic properties of fluororubber

Abstract

AbstractIn order to study the influence of two‐stage vulcanization process on the hydrophobic characteristics of FKM, superhydrophobic surfaces were prepared based on template method (1000 mesh screen, 1600 mesh screen and 2000 mesh screen), and six kinds of FKM with micro‐rough surface were prepared by one‐stage vulcanization and two‐stage vulcanization process, respectively. At first, the influence of two‐stage vulcanization process on the physical and chemical properties of FKM was illustrated by characterizing the two‐dimensional convex structure, three‐dimensional roughness and chemical functional groups of FKM. Then, mechanical tests and wettability tests were carried out on different FKM prepared by primary vulcanization and secondary vulcanization. The results show that the hydrophobicity of FKM prepared by secondary vulcanization is improved compared with FKM prepared by primary vulcanization, and the contact angle of FKM prepared by secondary vulcanization can reach above 165°. The secondary vulcanization process enhances the hydrophobicity of FKM mainly by increasing the longitudinal size of the convex structure on the surface of FKM, homogenizing the sizes of the convex structure and pits on the surface of FKM, and increasing the roughness of FKM surface. In addition, in the process of secondary vulcanization, the chain reaction of FKM matrix occurred. In the matrix, the hydrophilic group OH disappears, and the polar hydrophilic group becomes nonpolar hydrophobic group.