Sílica Precipitada e Tratada

Sílicas tratadas e precipitadas são sílicas amorfas sintéticas finas usadas em polímeros para reforçar, espessar e controlar a sedimentação. Precipitated silica is the workhorse reinforcing filler for rubber; surface-treated (hydrophobic) fumed silica is the rheology and anti-settling additive for filled and liquid systems. The dividing line is surface chemistry: a hydrophilic surface bonds water and polar groups, while a silane-treated hydrophobic surface disperses into non-polar resins and rubber. Match the surface to the polymer, not just the particle.

Precipitated silica (CAS 112926-00-8) is the reinforcing filler behind silica-tire technology and a wide range of technical rubber goods. It raises tensile strength, tear resistance, and abrasion resistance, and in tire treads it lowers rolling resistance versus carbon black. The honest trade-off: its hydrophilic surface resists dispersion in non-polar rubber and pushes compound viscosity up, so it is almost always run with a sulfur-functional coupling silane such as TESPT. Specify it where wet grip and rolling resistance matter.

Surface-treated fumed silica (CAS 68909-20-6) carries the same reinforcing structure with a silane-modified, water-repelling surface. That treatment lets it disperse into resins, adhesives, and liquid silicones without absorbing atmospheric moisture, where it builds thixotropic viscosity and stops fillers and pigments from settling. Treated grades cost more than untreated silica and interact less with polar binders. Reserve them for non-polar or moisture-sensitive systems; for aqueous or polar formulations, an untreated hydrophilic grade is usually the better and cheaper choice.

• Carga reforçante para bandas de rodagem de pneus, artefatos técnicos de borracha e compostos elastoméricos
• Reologia tixotrópica e controle antiescorrimento em adesivos, selantes e resinas líquidas
• Auxiliar antissedimentação e de suspensão de pigmento em sistemas poliméricos e de tintas com carga
• Reforço de borracha de silicone líquida (LSR) e de compostos de silicone de alta consistência
• Aditivo antiaglomerante e de fluidez em pós poliméricos e masterbatch

• Hydrophobic treated silica — PubChem
• Precipitated silica — PubChem
• Silica dimethyl silylate — PubChem