The overall blending method is to mix the silane coupling agent stock solution into the resin or polymer before the filler is added. Therefore, it is required that the resin or polymer should not react with the silane coupling agent prematurely, so as not to reduce its thickening effect. In addition, before the material is cured, the silane coupling agent must migrate from the polymer to the filler surface, and then complete the hydrolysis condensation reaction.
For this reason, a metal carboxylic acid ester can be added as a catalyst to accelerate the hydrolysis condensation reaction. This method is particularly convenient and effective for fillers suitable for the surface treatment of silane coupling agents, or for systems where the resin and fillers need to be mixed and stirred before molding, and it can also overcome some of the disadvantages of the filler surface treatment method. Some people use various resins to compare the advantages and disadvantages of the blending method and the surface treatment method. It is believed that, in most cases, the blending method is less effective than the surface treatment method. The effect of the blending method is that the silane coupling agent migrates from the resin to the surface of the fiber or the filler, and then interacts with the surface of the filler.
Therefore, after the silane coupling is incorporated into the resin, it must be left for a period of time to complete the migration process, and then cured, to obtain better results. It is also theoretically speculated that the reason that the silane coupling agent molecules migrate to the surface of the filler is only equivalent to the amount of monomolecular layer formed on the surface of the filler, so the amount of silane coupling agent only needs 0.5% -1.0% of the mass of the resin. It should also be pointed out that in the formulation of composite materials, when using additives with good surface compatibility and low molar mass of the filler, special attention should be paid to the order of feeding, that is, the silane coupling agent is added first, and then the additives are added to obtain a Good results.