ABSTRACT
I. Introduction Phenolics are important duroplastic materials with numerous
applications in fields that demand high strength, heat resistance, excellent fireproof properties, dimensional stability, and good electrical and thermal isolation properties all combined with low production costs. Two types of oligomers, a novolac or a resole, are used to make most phenol-methanal products and must be understood before applications, chemistry, and processing are presented. Novolacs are step reaction products of methanal and phenol at a mole ratio of less than one, reacted under acidic conditions. Molecules in a novolac prepolymer can have up to 10 aromatic rings connected by -CH2bridges and contain only aromatic hydroxyl groups. Resoles are step reaction products of methanal and phenol at a mole ratio greater than one, reacted under basic conditions. Molecules in a resole are small oligomers containing methylol groups, -CH2OH. The application of phenolic materials covers moldings, laminates, coatings, castings, ion exchange resins, rubber vulcanizing agents, different adhesives and binders, friction materials, composites, and resists for high technology application [1-9]. A general introduction to the technology of each of these applications follows in the order just given.
