These include the polycondensations used for making nylon and polyesters. In the world of adhesives and sealants, the group includes epoxies, urethanes, silicones and formaldehyde resins. Some typical reactions - involving both polycondensations and polyadditions - are shown below.

Epoxies: The most common epoxy resin used in adhesives is the diglycidyl ether of bisphenol A (DGEBA). This is typically cured with amine or mercapto hardeners. Note that the cure reaction with a primary amine leaves an additional amino hydrogen which can further react with epoxide groups.

Urethanes: The two most common reactions are those between a di- or polyisocyanate, eg diisocyanatodiphenylmethane (MDI) and a polyol (perhaps a polycaprolactone diol), (a), or between an isocyanate terminated prepolymer and atmospheric moisture (b).

Silicones: Silicone sealants are based on polydimethyl siloxanes. They typically contain a crosslinker, methyl triacetoxysilane, and are cured by atmospheric moisture. The curing reaction generates ethanoic acid, which accounts for the distinctive smell that you encounter if you use these products around the house.

Formaldehyde resins: These are most commonly used in a particular subset of adhesives: binders (eg for woodchip). They are produced by reacting methanol with a variety of active hydrogen compounds, notably phenol, urea and melamine.