Method of making a cyanate ester foam

1. A method of making a cyanate ester foam, comprising:

forming a resin mixture comprising at least one cyanate ester resin and a isocyanate foaming resin, thereby providing a total resin mixture of hundred parts by weight;

adding a catalyst/water mixture to the resin mixture at a temperature sufficient to keep the resin mixture reacting to form a foaming resin; and

curing the foaming resin to make a solid cyanate ester foam.

2. The method of claim 1 , wherein the at least one cyanate ester resin comprises a phenolic novolac-based cyanate ester resin.

3. The method of claim 1 , wherein the isocyanate foaming resin is derived from a polymeric methylene diisocyanate.

4. The method of claim 1 , wherein the resin mixture comprises between 70 and 99 parts of the at least one cyanate ester resin and between 1 to 30 parts of the isocyanate foaming resin.

5. The method of claim 1 , wherein the resin mixture further comprises a co-curative.

6. The method of claim 5 , wherein the co-curative comprises an epoxy- or polyol-based curing agent or a combination thereof.

7. The method of claim 5 , wherein the resin mixture comprises between 50 and 90 parts of the at least one cyanate ester resin, between 1 to 30 parts of the isocyanate foaming resin, and less than 35 parts of the co-curative.

8. The method of claim 1 , wherein the catalyst comprises a nucleophilic compound.

9. The method of claim 8 , wherein the nucleophilic compound comprises an imidazole compound with a substitution group on the tertiary nitrogen.

10. The method of claim 9 , wherein the imidazole compound comprises 1-methyl imidazole.

11. The method of claim 1 , wherein the catalyst is added at a concentration of less than approximately 2 parts per hundred parts of the total resin mixture.

12. The method of claim 1 , wherein the water is added at a concentration of less than approximately 3 parts per hundred parts of the total resin mixture.

13. The method of claim 1 , further comprising adding a surfactant to the resin mixture prior to adding the catalyst/water mixture.

14. The method of claim 13 , wherein the surfactant is selected from the group consisting of an anionic surfactant, a cationic surfactant, and a non-ionic surfactant.

15. The method of claim 13 , wherein the surfactant is selected from the group consisting of an organo polysiloxane compound, an amine alkylbenzene sulfonate compound, an alkyl phenol ethoxylate compound, a silicone-based non-ionic compound, a poly ethyleneoxide block non-ionic compound, and a nonionic alkoxylate-polyethylene glycol mono(nonyl phenyl)ether compound.

16. The method of claim 13 , wherein the surfactant is added at a concentration of between approximately 0.1 pph and approximately 1 parts per hundred parts of the total resin mixture.

17. The method of claim 1 , further comprising adding an inorganic additive to the resin mixture.

18. The method of claim 17 , wherein the inorganic additive is selected from a group consisting of clay, wollastonite, and mica.

19. The method of claim 1 , wherein the curing step comprises heating the foaming resin to a temperature greater than 50° C. for sufficient time to achieve solidification of the cyanate ester foam.

20. The method of claim 1 , further comprising heating the cyanate ester foam to a temperature greater than 400° C. in a non-oxidative atmosphere to provide a carbonaceous char foam.

21. A cyanate ester resin mixture, comprising at least one cyanate ester resin of between approximately 50 wt % and 90 wt %, an isocyanate foaming resin of between approximately 1 wt % and 30 wt %, a co-curative of less than approximately 35 wt % the mixture further comprising a catalyst/water mixture of less than approximately 3 parts per hundred of the resin mixture.

22. The cyanate ester resin mixture of claim 21 , further comprising a surfactant of less than approximately 1 parts per hundred of the total resin mixture.