This unification indicates the procedure for obtaining an approximate measurement of free ammonia and ammonia compounds in phenolic molds. It consists in obtaining an aqueous extract obtained hot from a molded piece reduced to the state of powder, in distilling this aqueous extract in the presence of sodium hydroxide and in subsequently determining the ammonia content in the distillate. However, with the present method an absolute determination of the free ammonia present is not achievable. Knowledge of the free ammonia content can be particularly interesting in cases where there is the possibility of corrosion of the metal inserts or contamination of foodstuffs.
UNI 4299-1959 history
1959UNI 4299-1959 Plastic material testing. thermohard material