Are rubber and latex the same thing?

Rubber and latex are not the same, but many people use the words as if they both referred only to natural rubber, which is the material derived from the milky white sap of rubber trees. There are a large number of materials characterized as rubbers or, more generally, as elastomers. These vary widely in chemical structure and application, all synthetic except for natural rubber.

Chemically speaking, latex is a dispersion of extremely small particles of an insoluble liquid or solid material in a liquid. The particles are almost always polymeric, and the liquid is usually water. Most latexes also contain a surfactant to keep the dispersion stable. Water-based paint is latex, and so are the starting materials used to make ordinary rubber gloves. Natural rubber latex is used to make natural rubber gloves, nitrile rubber latex is used to make nitrile rubber gloves, and so on.

Unfortunately, "latex" is also a synonym for natural rubber. Before the first few decades of this century, natural rubber latex (rubber tree sap) was unique. So, at that time, there was no confusion when the terms "latex" and "processed natural rubber" were used interchangeably.

Later in this century, when scientists finally began to understand the physical and chemical nature of natural rubber latex, they realized that synthetic versions could be made and began to use the word "latex" as it is defined above--as a general term for the physical and chemical phenomenon.