Since the development of the gypsum board, people have become more demanding on the board’s weight. Under the premise of ensuring strength, gypsum boards with a smaller unit weight are more and more popular. It saves transportation costs, reduces construction personnel’s labour intensity, and facilitates its application in high-rise buildings. Therefore, the foaming agent is a vital additive in gypsum board, which directly affects the quality and unit weight of gypsum board.

Inappropriate selection of foaming agent causes a small amount of foam, poor foam stability, fewer pores, and different sizes in the finished gypsum board. This gypsum board is prone to defects, which are manifested by the board’s considerable unit weight. The board is relatively brittle, and even the foam is concentrated in the gypsum slurry. The surface layer of the pulp affects the bonding between the board core and the paper. This phenomenon is particularly prominent in the board made of desulfurized gypsum. 

The gypsum board with an excellent foaming agent has many equally distributed pores, and the board possesses lightweight.