Methyl methacrylate (MMA) is an unsaturated ester that has several uses in polymer manufacturing. It is a clear liquid with a characteristic ester odor.

There are several synthetic routes to MMA. The most widely used are a three-step sequence that begins with acetone and HCN and proceeds through acetone cyanohydrin; and a two-step process that begins with the reaction of ethylene and methanol to produce methyl propionate.

By far the greatest volume of MMA is polymerized to the homopolymer poly(methyl methacrylate) (PMMA). The polymer is a clear plastic that is known by the familiar trade names Lucite and Plexiglas.

MMA is also copolymerized with styrene and butadiene to make an additive to poly(vinyl chloride) (PVC) that improves its properties. MMA is also transesterified to make specialty methacrylate monomers.