Formation of a glass‐ionomer cement based on an lon‐leachable glass and polyacrylic acid

The chemistry of the cement‐forming reaction between a fluorine‐containing calcium aluminosilicate glass and aqueous solutions of poly(acrylic acid) has been studied using infrared spectroscopy and classical chemical procedures. It was concluded that calcium, aluminium and fluoride ions were leached from the glass leaving a relict of silica gel. These ions migrated into the polyelectrolyte phase where the cations cross‐linked polyanionic chains causing the system to gel. Initial set, which takes place within 10 minutes, was attributed to the formation of the calcium salt, the aluminium salt forming later and contributing to the hardening of the cement. Reactions continued for at least 48 h. The role of ion‐binding in the reaction is discussed.