Alkalinity and pH of Natural Rubber Latex

Manufacturer:  We would like to know about difference between HA & LA type NR latex for its properties like pH , NH3 content etc . If their pH difference is less how NH3 content would be less? Also let us know if ammonia is removed from latex to 0.2% what will be pH.  Please include any further details.


John Woon (Senior Latex Consultant):  Generally, as the ammonia level is reduced either chemically (using formaldehyde) or by blowing hot air over it while stirring, the pH would also drop.

However, the non-rubber constituents of natural rubber latex could sometimes act as a buffer. Hence the pH might change only slightly despite a greater change in ammonia level. Different batches of latex might behave differently for obvious reason.

The best way to confirm this is to conduct lab tests by determining the different levels of ammonia content i.e. the alkalinity using ASTM method and measuring the pH of the corresponding latex samples.