Coupling agents can be generally divided into: silane coupling agents, titanate coupling agents and other types of coupling agents according to their chemical structures. Generally, the functional groups at both ends of the coupling agent react with the dispersed phase of the filler and the matrix polymer, respectively. Due to different fillers, the coupling effect is very different. For example, silane coupling agent has a significant effect on silica, aluminum oxide, glass fiber, clay, silicate, silicon carbide, etc. Aluminum, wollastonite, iron powder, alumina, etc. are slightly less effective, less effective on asbestos, titanium dioxide, ferric oxide, etc., and have little effect on calcium carbonate, graphite, carbon black, barium sulfate, calcium sulfate, etc. .

For fillers with thiol groups on the surface, the coupling effect of silane coupling agents is large, while for carbonates, sulfates, sulfites, etc. of calcium, magnesium and barium, the coupling effect of silane coupling agents is not obvious. . If the surface of filler particles without thiol groups is treated with a hydrosol of silica, and then a silane coupling agent is used, a better coupling effect will be produced at this time. This treatment method is called double coating method.

Both the titanate coupling agent and the aluminate coupling agent can treat the surface of the filler, but the effect of the treatment has a certain specificity. For example, the fillers with better treatment effect of titanate coupling agent are calcium carbonate, barium sulfate, calcium sulfate, calcium sulfite, aluminum hydroxide, magnesium hydroxide, calcium silicate, aluminum silicate, titanium self-powder, asbestos, oxide Aluminum, ferric oxide, lead oxide, ferrite, etc.; fillers with less treatment effect include mica, silica, magnesium oxide, calcium oxide, etc.; fillers with poor treatment effect include talcum powder, carbon black, wood powder ; There are almost no effect of graphite, magnetic powder, clay, general pigments, etc. However, it should also be determined according to the specific variety, brand, and dosage of the coupling agent.