Sealants and adhesives are important products that are often used in high amount in all aspects of production and daily life, and they are widely used in many fields including construction, transportation, production of electronic instruments and parts etc.

In the past, due to the limitations in nanotechnology, China lagged behind in the production of sealants and adhesives and relied heavily on imports for high-end products because that foreign companies in the field had already adopted nanomaterials as modifiers, which help ensure that their sealant and adhesive products can reach the best viscosity, fluidity and curing speed. As the domestic fumed silica industry breaks the foreign hold on related technologies, China's own adhesive and sealant industry will soon see rapid development.

Fumed silica (also known as pyrogenic silica, colloidal silicon dioxide) is the preferred material for modification of adhesives and sealants. In addition to significantly increasing the bonding strength and ensuring free flow, the addition of fumed silica into silicone sealants and adhesives also helps prevent caking, sag, collapse, depression during curing, maintain transparency, as well as improving strength and shear resistance etc. In terms of action mechanism, after dispersing in sealants and adhesives, the silicon hydroxyls on the surface of fumed silica promote the generation of hydrogen bonds between different particles and in turn the formation of a network of silica aggregates, which gives rise to thickening action by limiting the fluidity and increasing the viscosity within the system; under the action of shearing force, the silica network will be destroyed, resulting in a decrease in the viscosity of the system and a thixotropic effect, making it convenient for construction applications. Once the shearing force is eliminated, this network structure can be re-formed to effectively prevent sagging during the curing process.

Produced by HUBEI HUIFU NANOMATERIAL CO.,LTD. （former company name : Yichang Huifu Silicon Material Co., Ltd.）, HL-150\HL-200 hydrophilic fumed silica are widely used in adhesives and sealants, paints, silicone rubber, unsaturated resins due to their good thickening, thixotropic, anti-caking and anti-settling properties. Other products of the company such as HB-132\HB-135\HB-139 silazane, siloxane-modified（HMDS-Treated） hydrophobic fumed silica and HB-151\HB-152 chlorosilane-modified ( DDS-Treated ) hydrophobic fumed silica also have seen extensive applications in above mentioned fields.