There are three main surface treatment methods for glass fibers: post-treatment, pre-treatment, and migration.

       (1) Post-processing method

       This is a method commonly used at home and abroad. All textile sizing agents, such as glass fiber products prepared with paraffin wax emulsion, must be treated with post-treatment to make FRP. This method is carried out in two steps. Firstly, the textile sizing agent on the surface of the glass fiber product is removed by washing or burning, and then dipped in the coupling agent solution, washed with water, and dried to cover the surface of the glass fiber with a silane coupling agent.

 

       (2) Pre-processing method

       This method is to change the formula of the sizing agent in the preparation of glass fiber, and add the silane coupling agent as a component to the sizing agent, so that the sizing agent can not only meet the requirements of glass fiber drawing, weaving and various processes, but also in the drawing process. In the process, the glass fiber surface is covered with a layer of coupling agent. The glass fiber products prepared by the pre-treatment method can be directly used to make FRP, eliminating the need for the complicated process of washing or burning and post-processing, and avoiding the strength loss of the glass fiber during burning. Therefore, the pretreatment method is an advanced glass fiber surface treatment method, and the research on the formulation of the sizing agent suitable for the pretreatment method has become an important topic.

 

       (3) Migration method

       In the migration method, the silane coupling agent is directly added to the resin glue solution and mixed, and the migration of the silane coupling agent from the resin glue solution to the surface of the glass fiber reacts with the surface of the glass fiber to produce a coupling effect.

       The advantage of the migration method is that the process is easy to operate, does not require large and complex processing equipment, and does not consume energy. But the effect of the migration method is worse than the first two methods.