Fotopolymer

Fotopolymer, more commonly called photopolymer, is a polymer that hardens or crosslinks when exposed to light. The light activates photoinitiators in the material, generating reactive species that initiate polymerization of surrounding monomers and oligomers to form a solid network. The process typically uses ultraviolet or visible light, depending on the initiator chemistry.

Photopolymers are formulated as resins, pastes, or gels and usually contain acrylic or methacrylic monomers or oligomers, photoinitiators, stabilizers, and often pigments or fillers. They are widely used in processes that rely on light to shape materials, such as stereolithography (SLA) and digital light processing (DLP) 3D printing, photoresists in microfabrication, dental composites, coatings, adhesives, and holography.

Curing occurs when the material is irradiated with the appropriate wavelength, triggering rapid polymerization and crosslinking. Surface exposure can be affected by oxygen, which may inhibit curing near the air interface. Post-curing, often achieved with additional light and sometimes heat, can increase hardness, modulus, and chemical resistance.

Advantages of photopolymers include high resolution, smooth surface finish, and low processing temperatures, making them suitable for intricate parts and thin films. Limitations include brittleness in cured resins, the potential for residual uncured monomer, sensitivity to oxygen, and safety considerations for handling uncured materials.

Safety and environmental considerations emphasize proper ventilation, protective equipment, and complete curing to minimize exposure. Ongoing research explores bio-based formulations, tougher or tougher-toughened systems, and dual-curing approaches to expand performance and sustainability.