Condensation polymerization for phenol formaldehyde: Phenol formaldehyde resins are synthetic polymers obtained by the reaction of phenol with formaldehyde(Bakelite). used for the production of molded products including billiard balls, laboratory countertops, and as coatings and adhesives. Used for fire-resistant circuit board materials. There are two main production methods. One reacts phenol and formaldehyde directly to produce a thermosetting polymer, while the other restricts the formaldehyde to produce a prepolymer which can be moulded and then cured with the addition of more formaldehyde and heat
Phenol reacts with formaldehyde at the ortho and para sites (sites 2, 4 and 6) allowing up to 3 units of formaldehyde to attach to the ring. The initial reaction in all cases involves the formation of a hydroxymethyl phenol:
The hydroxymethyl group is capable of reacting with either another free ortho or para site, or with another hydroxymethyl group. The first reaction gives a methylene bridge, and the second forms an ether bridge: