Polyurethane is a polymer. The name 'polymer' is derived from “poly meros”, Greek for “many parts,&rdquo and is like a chain, repeated links that make up one large whole. The links in the chain are called monomers [1].

In the case of the polyurethane chain, the links are urethane monomers which resemble the chemical structure of the natural urethane product, repeating -NH-CO-O-units [2].

The way the foam looks, how it feels, how it shapes, and all other physical properties depend on the composition and length of the polyurethane chain.

The polyurethane chain is formed by the reaction of urethane monomers with another chemical called an isocyanate. The isocyanate is known as the blowing agent; when you hear the phrase "blowing foam" that person is refering to the mixing of two liquids, urethane monomers and some form of isocyanate, to make foam.

Polyurethane “foams” because of a reaction between the isocyanate and water. The reaction emits CO2, which is embodied as a bubble in the foam.

This reaction is necessary for polyurethane to foam, and how this reaction takes place determines the size and shape of the cells, or bubbles, of the foam. The better and safer the isocyanate used is, the safer the foaming process and more sustainable the foam.

Isocyanates are toxic because of the chemical structure known as a benzene ring. Benzene rings are highly reactive to other molecules. The molecule that is known as TDI is small in size and gets airborne easily. TDI is a respiratory hazard to humans and becuase of the reactive nature of the benzene ring, once TDI is is inside the human body it can easily infilrate the human DNA and cause cancer.

One way to reduce the health issues of the isocyanate molecule is to ensure that it is less likely to get into the air. This is a direct function of size and weight. The larger and heavier the molecule, the less likely it is to be airborne.

Most surfboard blanks companies use TDI despite the harmful effects because, until now, it has been difficult to make high quality surfboard foam with other isocyanates that get less airborne.

The Sonicfoam process allows us to produce TDI-free polyurethane foam without any loss of quality.

[1] Teegarden, David. Polymer Chemistry: Introduction to an Indispensable Science. NSTA Press: 2004.