What type of polymer is phenol formaldehyde?

Phenol formaldehyde is classified as a thermosetting polymer. This type of polymer exhibits specific behavior when exposed to heat. Unlike thermoplastics, which can be melted and reshaped multiple times, thermosetting polymers undergo a curing process during their initial heating that causes them to set into a permanent, irreversible shape. Once cured, they cannot be remelted or reshaped; instead, they maintain their structural integrity even under high temperatures and stress.

Phenol formaldehyde undergoes a cross-linking reaction during its curing process, leading to a hard, inflexible material that is resistant to heat and chemical exposure. This characteristic makes it ideal for applications such as adhesives, coatings, and molded items.

In contrast, elastomers are flexible polymers that can stretch and return to their original shape, and additives are materials incorporated into polymers to enhance certain properties. These distinctions highlight why phenol formaldehyde is definitively classified as a thermosetting polymer.