Methyl methacrylate (MMA) is a monomer unsaturated ester. It has a variety of uses in polymer manufacturing. The primary use of MMA monomer is in the formation of Poly(methyl methacrylate) (PMMA) homopolymers. PMMA is a clear and hard synthetic plastic.

In addition, MMA is the basis for many acrylate polymers and is an essential copolymer monomer in the formulation of paints, coatings and adhesive resins. Applications include safety glass, exterior paints, vinyl impact modifiers, adhesives, lighting displays, etc. MMA is also copolymerised with styrene and butadiene to make additives for polyvinyl chloride (PVC) to improve its properties. MMA is also ester-exchanged in order to make specialty methacrylate monomers.

PMMA is used in industry to produce cast and extruded acrylic sheets. These cast PMMA sheet products have good optical clarity, high transparency and UV stability. It is also compatible with human tissue. It is therefore used in a variety of medical technologies, such as acrylic bone cements and internal lenses for eye implants. Research is currently underway to develop high performance PMMA nanocomposites such as carbon nanotubes, carbon black and carbon fibres.

MMA and PMMA are both commonly used organic reagents for plastics and construction materials. MMA is the upstream monomer of PMMA, while PMMA is one of the main downstream products of MMA. However, MMA can cause safety problems in direct contact with the skin and eyes, and lead to serious problems in the nose, passages and lungs. PMMA, in contrast, is compatible with human tissue.