Phosphorus-containing thermosets obtained by cationic copolymerisation of glycidyl compounds with a spiroorthoester or γ-butyrolactone

The incorporation of phosphorus in the networks increases the LOI values and all crosslinked polymers showed a slight shrinkage after curing, much lower than that observed in conventional epoxy resins. The materials from preformed SOE showed lower shrinkage than the analogues from lactone and epoxy groups.