Sodium Naphthalene Sulfonate Formaldehyde (SNF) 36290-04-7

Sodium Naphthalene Sulfonate Formaldehyde (SNF), also known as PNS or FDN, is a naphthalene-based superplasticizer produced by condensing naphthalene sulfonic acid with formaldehyde . It is a beige to brown powder with 92% solid content, widely used as a high-range water reducer in concrete to improve workability and strength while reducing water content .

SNF works by dispersing cement particles through electrostatic repulsion. The negatively charged sulfonate groups on the SNF polymer adsorb onto cement particle surfaces, creating a negative charge that separates the particles. This releases trapped water, reducing the water-cement ratio by 18-25% while maintaining or improving concrete workability. The result is higher strength concrete with improved durability and surface finish .

The typical dosage rate for SNF is 0.5-1.5% by weight of cementitious material. The exact dosage depends on the desired water reduction, type of cement, aggregates, and ambient temperature. Trial mixes are recommended to determine the optimal dosage for specific applications. SNF can be added directly as powder or dissolved in water before addition .

SNF is suitable for ready-mix concrete, precast and prestressed concrete, high-strength concrete, flowing concrete, pumped concrete, and steam-curing concrete. It is particularly effective in areas of congested reinforcement where high workability is needed. SNF can also serve as a base material for producing compound admixtures such as accelerating water-reducing, retarding water-reducing, and pumping aid formulations .

SNF powder should be stored in a dedicated, well-ventilated, and dry warehouse away from moisture. The product is hygroscopic and will absorb moisture if exposed to humid conditions. Packed in 25kg bags or 650kg jumbo bags. When properly stored in sealed packaging, shelf life is minimum 12 months. After the expiration date, the product can still be used if testing results are qualified .