Drywall

Drywall is a panel made of gypsum with or without additives. It is also known as plasterboard, wallboard, sheet rock, gypsum board, buster board, custard board, or gypsum panel. It is usually extruded between thick sheets of facer and backer paper. It is used in the construction of walls and ceilings that are inside a building.
Manufacture.
Drywall is made up of a layer of gypsum plaster sandwiched between two layers of paper. The plaster is mixed with fibre, plasticizer, foaming agent, finely ground gypsum crystal as an accelerator, EDTA, starch or other chelate as a retarder. Various additives may be added to decrease mildew and increase fire resistance.