phenolformaldehyde

Phenol-formaldehyde, commonly called phenolic resin, is a synthetic polymer produced by the condensation of phenol with formaldehyde. Under controlled conditions it forms thermosetting resins that cure into rigid, heat-resistant plastics and bond materials in a variety of applications.

Two main families exist: novolac resins, formed with a low ratio of formaldehyde, which require a curing agent to crosslink; and resole resins, formed with excess formaldehyde, which can cure thermally or with catalysts without extra crosslinkers. The polymer network features methylene and ether linkages between phenyl rings.

Historically, phenol-formaldehyde was developed in the early 20th century by Leo Baekeland, leading to Bakelite, one of the first fully synthetic plastics. It found early use in electrical insulators and durable housings, and it remains important in many high-performance applications.

Today phenolic resins are used in decorative and structural laminates, molded parts, heat-resistant coatings, adhesives, and as binders in foundry sands and abrasive products. They are valued for fire resistance, chemical stability, and electrical insulation, but can be brittle and may release formaldehyde during aging or improper curing.

Manufacture and handling involve formaldehyde, a hazardous substance. Industrial use requires appropriate controls, ventilation, and protective measures. Phenol and formaldehyde exposures are regulated to minimize health risks, and finished products are evaluated for residual formaldehyde emissions.