https://doi.org/10.1351/goldbook.15307
Polymer composed of macromolecules containing triazine rings in the backbone: 
Notes:
- A polytriazine is usually a branched or network polymer:
- A polycyanurate and an amino polymer prepared from 1,3,5-triazine-2,4,6-triamine (trivial name: melamine) are excluded; however, these polymers can be regarded as subclasses of polytriazines.
- A molecule of a typical polytriazine contains 1,3,5-triazine rings, however, polytriazines containing 1,2,4-triazine rings and, less likely, 1,2,3-triazine rings are also possible.