摘要：The mechanism of action of coupling agents has not yet formed a complete theoretical system, but existing theories such as chemica

The mechanism of action of coupling agents has not yet formed a complete theoretical system, but existing theories such as chemical bond theory, wetting effect and surface energy theory, deformable layer theory, and confinement layer theory have been widely discussed. Among them, chemical bond theory is considered the most comprehensive theoretical framework. This theory suggests that specific chemical functional groups in coupling agent molecules can react with protons on the surface of inorganic fillers to form covalent bonds, while another type of functional group can bond with polymer molecules, thereby achieving bridging between inorganic and organic phases and significantly enhancing interfacial bonding strength.

The molecular structure differences of titanium ester coupling agents result in different functional characteristics, so targeted selection should be made according to the resin type and filler characteristics during the coupling process. This type of coupling agent undergoes a chemical reaction with trace hydroxyl or proton groups adsorbed on the surface of the filler through alkoxyl groups, thereby forming a monolayer on the surface of the filler.

It is worth noting that the differences in coupling groups of different titanium ester coupling agents result in significant differences in their adaptability to the moisture content of fillers. In general, monoalkoxy coupling agents are suitable for low moisture dry fillers containing only bonded water, while chelating coupling agents are more suitable for high moisture inorganic filler systems.

After determining the type of coupling agent, its dosage has a significant impact on the coupling effect. Experimental data shows that with the increase of coupling agent dosage, the coupling effect and impact strength of the filling system both show an upward trend. However, experiments on rigid PVC filling systems have found that excessive use of coupling agents can lead to increased costs and decreased mechanical properties. This phenomenon may be due to the adsorption of excess coupling agent residues, which in turn have a negative impact on the coupling effect.

来源：躺平闲聊天