Ammonium salts increasing chemical resistance

The polymer of MMA is known as Perspex. It is a clear transparent glasslike material with high hardness, resistance to fracture, and chemical stabihty. As shown by reaction 4.5.1, the conventional route for the manufacture of MMA involves several steps. This process generates large quantities of ammonium salts, thereby increasing the E factor significantly (see Section 1.6 and reaction 1.6.1). 

Leach-Resistant Chemicals. Insoluble Complexes. Leach-resistant fire retardants can be formed by reacting soluble salts with metal salts to form insoluble, metallic salt complexes. Sodium silicate reacted with calcium chloride formed an insoluble, hydrated calcium silicate (95). Application of a 20% diammonium phosphate solution, followed by a 20% magnesium sulfate solution, has been proposed as a ready-to-use treatment for wood roofs (96). This combination forms an insoluble magnesium ammonium phosphate and is recommended for roofs that are 5 years old or older. Test results indicate that this treatment provides increased flame-spread protection. 

---