Silicone Rubber

Why add fumed silica to silicone Rubber

HIFULL fumed silica in silicone rubber improves mechanical strength. Silicone rubber is aging-resistant, high and low temperature resistant and electricity-insulated. However, the molecular chain of silicon rubber is soft, and the interaction force is weak, so silicon rubber needs to be reinforced before actual usage.

advantages of fumed silica in silicone rubber

  • Super high reinforcement performance, improve the base rubber strength by 40 times;
  • Greater elongation and tensile strength, avoiding whiting or break;
  • Higher toughness, hardness and resilience of the rubber body;
  • Low impact on transparency or clarity;
  • Better performance on heat resistance, aging resistance and dielectric property;
  • Excellent thickening & thixotropic properties, shorten the mixing time.

Fumed silica is an ideal reinforcing agent for silicone rubber. The strengthening is fundamentally brought about by silanol groups being interacted with or Si-methyl bonds being radically cleaved into the polymer. The surface silanol groups (Si-OH) of fumed silica react with silicone rubber macromolecule, then generate a silicon rubber molecular adsorption layer on the surface of silica, then a three-dimensional network structure is formed. This structure effectively limits the deformation of the silicone rubber molecular chain, thereby achieving the reinforcing effect.

Types of Silicone RubberFunctions
Room temperature-vulcanized (RTV) silicone rubberimprove tensile strength, abrasion resistance and hardness;
High temperature-vulcanized (HTV) silicone rubbergreatly improve its strength, hardness and tear resistance
High-transparent or high-strength silicone productsmaintain great clarity, toughness, hardness and resilience
Medical-grade siliconenon-toxic, non-hazardous, high safety, improve the mechanical strength
Foamed flame retardant silicone rubberFumed silica works as reinforcing filler to ensure the strength of porous famed materials
Liquid silicone rubber (LSR)reinforce, improved tear resistance, high-temperature resistance, thickening thixotropy and high transparency
Ceramic silicone rubberreinforcement, improve material elastic deformation performance and tensile strength, flame retardant

Fumed Silica Grade Recommendation for Paint & Coatings

  • White nanoparticle size powder
  • High purity
  • High specific surface area(140 – 400㎡ /g)
  • Applicable to water-based and oil-based chemical products
  • Recommended Dosage: 6%-40%
  • Recommended HIFULL products for silicon rubber application:
  • Hydrophilic Grades: HL-150, HL-200, HL-380
  • Hydrophobic Grades: HB-151 ( DDS-treated ), HB-630 ( HMDS-treated )


Our main products are fumed silica SiO2, fumed titanium dioxide TiO2, and fumed alumina Al2O3. We get 20+ years of expertise and 20,000 tons of annual capacity. We supply total of 23 grades of hydrophilic & hydrophobic fumed silica. We get registration of REACH and pre-registration of K-REACH & KKDIK. We are the leading setting body of ISO18473-1:2015ISO18473-3:2018, and ISO 23157:2021. Learn More About Hifull

Other Application

Hello, Customers

My name is Van, I’m the business manager of HIFULL, I have been in Fumed Silica Industry for more than 10 years. Feel free to contact me. I’m happy to provide you the best service and products.
Business Manager