A dopamine-like deposition coatings on the polyethylene terephthalate fibers and its interface adhesion with rubber

In this paper, a dopamine-like deposition coatings were constructed on the fibers surface by the specific reaction characteristics of catechol (CA) and triethylenetetramine (TETA), which can form a large number of phenolic hydroxyl and amino reactive groups. Then, 1,3,5-triglycidyl isocyanurate (TGIC) or glyceryl tris-triglycidyl ether (GTE) with containing three epoxy groups was grafted onto the above fiber surface. The phenolic hydroxyl and amino groups can interact with the phenolic resin in the resorcinol-formaldehyde-latex (RFL) impregnation solution, while the epoxy groups can react with the latex in the RFL impregnation solution. Both of them can enhance the interfacial adhesion between fiber and rubber. The oxidation of catechol was tested by ultraviolet spectrophotometer (UV-vis). The fiber surface was observed by scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The mechanical properties of the fibers and the corresponding rubber composites were carried out using a universal testing machine. The results show that the fiber surface after co-deposition/reaction coatings contains a large number of phenolic hydroxyl, amino, and epoxy reactive groups. When the fiber was treated by the molar ratio of 3:1 of CA /TETA under UV irradiation for 2 h, and then was grafted by GTE of 42 wt% of (CATE plus TETA), an obvious increase of the fiber surface roughness can be observed. Accordingly, the fiber tensile strength is increased 13.94% compared to the pristine fibers. And the peel strength of the fiber/rubber composite can achieve 14.13 N/mm, which was 41.4% higher than that of the pristine fiber/rubber composite. The way is promising to provide a new ideas for the design and preparation of fibers/rubber composites with excellent mechanical properties.