Porous/nanoporous PHT
Methods of forming nanoporous materials are described herein that include forming a polymer network with a chemically removable portion. The chemically removable portion may be polycarbonate polymer that is removable on application of heat or exposure to a base, or a polyhexahydrotriazine (PHT) or polyhemiaminal (PHA) polymer that is removable on exposure to an acid. The method generally includes forming a reaction mixture comprising a formaldehyde, a solvent, a primary aromatic diamine, and a diamine having a primary amino group and a secondary amino group, the secondary amino group having a base-reactive substituent, and heating the reaction mixture to a temperature of between about 50 deg C. and about 150 deg C. to form a polymer. Removing any portion of the polymer results in formation of nanoscopic pores as polymer chains are decomposed, leaving pores in the polymer matrix.
1. A thermally stable polymer material comprising a porous polyhexahydrotriazine having average pore size less than about 100 nm and density less than about 1.5 g/cm 3 .
2. The thermally stable polymer material of claim 1 , further comprising carbon fibers.
3. The thermally stable polymer material of claim 1 , wherein the polyhexahydrotriazine is a material having a plurality of hexahydrotriazine units with the general structure
wherein at least one starred bond of each hexahydrotriazine unit is bonded to a hydrogen atom, and at least one starred bond of each hexahydrotriazine unit is bonded to a divalent linking group.
4. The thermally stable polymer material of claim 3 , wherein each divalent linking group has the structure
wherein L′ is a divalent linking group selected from the group consisting of —O—, —S—, —N(R′)—, —N(H)—, —R″—, and combinations thereof, wherein R′ and R″ independently comprise at least 1 carbon, and each starred bond of each divalent linking group is covalently bonded to a respective starred bond of a hexahydrotriazine unit.
5. A thermally stable polymer material comprising a porous polyhexahydrotriazine having average pore size less than about 100 nm and density less than about 1.5 g/cm 3 , wherein the thermally stable polymer comprises a plurality of hexahydrotriazine groups, a plurality of hemiaminal groups, or both.
6. The thermally stable polymer material of claim 5 , further comprising a plurality of divalent linking groups having the structure
wherein L′ is a divalent linking group selected from the group consisting of —O—, —S—, —N(R′)—, —N(H)—, —R″—, and combinations thereof, wherein R′ and R″ independently comprise at least 1 carbon, and each starred bond of each divalent linking group is covalently bonded to a hexahydrotriazine unit or a hem iaminal unit.
7. The thermally stable polymer material of claim 6 , wherein each starred bond of each divalent linking group is bonded to a nitrogen atom of a hexahydrotriazine group having the general structure
or a hemiaminal group having the general structure