The adhesion between rubber and fiber is mainly manifested as follows.

(1) Mechanical bonding. The rubber diffuses and penetrates into the gaps of the fibers, forming nails, anchors and inlays. Root fixation and other mechanical effects. This is one of the main roles of the rubber and fiber = bonding. Due to the high adhesion of solid rubber, poor mobility, rubber to the fiber gap China diffusion and penetration is not very adequate, there is still some air in the gap, the formation of the phase interface layer, so the direct use of rubber and fiber bonding, the effect is not ideal.

(2) physical bonding. Because many fiber surface with polarity, and contains -OH, -COOH, -NH- and other groups. When the rubber and fiber surface is fully close, there is a strong physical adsorption, rubber containing -OH, oxygen groups, nitrogen groups, etc. can also be with the fiber surface -OH, -COOH, -Si-OH to form hydrogen bonds, further increasing the oh adsorption. But because the polyester, aramid fiber surface -OH, -COOH number is very small, polar groups, shielded by the benzene ring, the polar molecules in the rubber is difficult to play a role with it, so the rubber and polyester, aramid fiber bonding, the physical bonding effect is weak. Cotton fibers, rayon, nylon fibers, glass fibers, physical bonding is stronger, becoming one of the bonding force.

(3) chemical bonding. For rubber and cotton fibers, rayon fibers, nylon, because the surface has a certain chemical reaction (-OH, -COOH), it is easier to cooperate with the rubber or rubber molecular chain chemical interaction, the formation of chemical bonds, easy to emerge strong and durable bonding. So rubber and cotton fiber, rayon, nylon fiber is easier to emerge a strong bond. The Si-O-Si group on the surface of glass fiber can be hydrolyzed into -Si-OH by water vapor in the air. -Si-OH has similar chemical reactivity as alcohol-OH, so it also has high chemical reactivity, and the coupling agent is used to treat the surface of glass fiber, so it can highlight the reaction between the coupling agent molecule and -OH on the surface of glass fiber. The coupling agent molecule also reacts with the rubber molecule. Thus, a strong bond between the rubber and the glass fiber fabric can be achieved. Due to the low chemical reactivity of the surface of the lift and aramid fiber, except for the end of the -OH can occur very little chemical interaction, other places do not have chemical interaction with the rubber. Therefore, the rubber is directly bonded with polyester and aramid fibers, and there is almost no chemical bonding, so the bonding effect is poor. In order to improve the adhesion between rubber and polyester, aramid fiber, polyester and aramid fiber must be surface modified treatment, such as dipping with a variety of reactive groups of dipping solution, plasma treatment, γ - ray treatment, ultrasonic treatment, etc., so that its surface with reactive groups. Then they are bonded to the rubber. Therefore, the rubber and various fibers to emerge a strong bond between the main rely on chemical bonding.

In order to enhance the mechanical bonding, physical bonding and chemical bonding between rubber and fiber, it is necessary to impregnate or coat various fibers, and add some substances that can react with the groups on the surface of the impregnated fiber to improve the bonding effect.