Fenolihartsi

Fenolihartsi, also known as phenol-formaldehyde resin or simply phenolic resin, is a type of synthetic polymer produced by the reaction of phenol with formaldehyde. It is one of the oldest and most widely used classes of thermosetting plastics, first developed in the early 20th century by chemist Leo Baekeland. These resins are known for their heat resistance, mechanical strength, and chemical stability, making them suitable for a variety of industrial and consumer applications.

The synthesis of phenol-formaldehyde resins involves the condensation polymerization of phenol and formaldehyde under acidic or basic catalysis. The resulting material undergoes cross-linking, forming a rigid, three-dimensional network that hardens upon curing. Depending on the conditions and ratios of reactants, different types of phenolic resins can be produced, including novolacs (formed under acidic conditions) and resols (formed under basic conditions), which require additional curing agents like hexamethylenetetramine.

Phenolic resins are valued for their durability and resistance to moisture, solvents, and high temperatures, often exceeding 150°C (302°F). They are commonly used in the manufacturing of electrical insulators, adhesives, molded plastic products, and composite materials. In the automotive industry, they are employed in brake linings and friction materials due to their friction properties. Additionally, phenolic resins are used in wood composites, such as plywood and particleboard, where they serve as binders.

Despite their advantages, phenolic resins have some limitations, including brittleness and poor resistance to ultraviolet light, which can cause degradation over time. They also release formaldehyde during production and curing, posing potential health risks if not handled properly. Modern manufacturing processes have improved safety and reduced emissions, but precautions remain necessary in industrial settings.