Sulphonated naphthalene formaldehyde, also known as SNF, is a type of synthetic polymer that is commonly used as a dispersant in the construction industry. It is derived from naphthalene and formaldehyde, and it is sulfonated to improve its solubility in water.

SNF is a versatile additive that is used to improve the flow and workability of concrete, particularly in applications where high-strength and durability are required. It works by reducing the surface tension of the water in the mix, which makes it easier for the cement particles to disperse and bond together.

SNF is typically added to concrete mixes in small amounts, usually between 0.5% and 1% of the total weight of the cement. It is available in powder form and can be easily mixed with other dry ingredients before being added to the concrete mix.

SNF is considered to be a safe and effective additive for use in concrete, and it has been widely used in the construction industry for many years. However, like all chemical additives, it should be handled with care and used in accordance with manufacturer instructions and industry best practices.