Gaseous silica/fumed silica can be used as a thickener and thixotropic agent in the field of adhesives, which can increase bonding strength, ensure free flow, and prevent agglomeration and sagging and collapse during curing.


When gas-phase silica is uniformly dispersed in the adhesive system, a network of silica aggregates can be formed. The aggregates form hydrogen bonds with the polymer through the surface silicon hydroxyl groups, limiting the fluidity of the system, increasing the adhesive strength of the system, and playing a thickening role; At the same time, under the action of shear force, the hydrogen bonds and silicon dioxide network are destroyed, leading to a decrease in the viscosity of the system, which results in a thixotropic effect and facilitates construction. Once the shear force is eliminated, the silicon dioxide network and hydrogen bonds are formed again, which can effectively prevent the adhesive from sagging during the curing process.


Meanwhile, fumed silica is a very effective reinforcing filler for cross-linked polymer systems, which can significantly improve the bonding strength of adhesives. On the one hand, this is attributed to the small size effect and large specific surface area of fumed silica particles; On the other hand, due to the presence of many silanol groups on its surface, a network structure can be formed between particles through hydrogen bonding and van der Waals forces. At the same time, silica particles also have strong interactions with polymer molecules, improving interfacial adhesion. Therefore, the bonding strength of the adhesive reinforced with white carbon black can be significantly improved, and the elongation at break can also be significantly improved.
In summary, fumed silica/fumed silica can play a role in the production and storage, construction and coating, as well as mechanical and performance aspects of adhesives, improving the performance of adhesives and sealants. Mainly reflected in the following aspects:






One is reinforcement, which mainly serves to increase the internal strength and bonding strength of the adhesive material, enhance the mechanical properties, toughness, and ductility of the adhesive material, improve tensile strength and elongation at break, and thus improve physical properties.






The second is thickening thixotropy, which mainly increases the viscosity and consistency of the adhesive material, improving the convenience of the adhesive material in application processes such as coating, dispensing, and sealing.






The third is to prevent sagging. Vapor phase silica can improve sagging and collapse during the curing process of the adhesive, increase excellent pseudoplasticity and high yield point, and reduce uncontrolled flow and loss of the adhesive during construction.






The fourth is to prevent sedimentation, reduce the settling phenomenon of fillers in the rubber material, and form a stable and uniform suspension.






The fifth is transparency. The addition of fumed silica does not change the original color of the adhesive, maintaining the ideal transparency of the adhesive.






The sixth aspect is stability and co dispersibility. Vapor phase silica can improve the stability of rubber material storage, provide long-lasting temperature resistance, fire resistance, and waterproof performance, greatly improve service life and adapt to various complex environments.