Triaryl-s-triazine ring

The graphite fiber reinforced triaryl-s-triazine ring (TSTR) cross-linked polyimides with ring-chain structures have good mechanical properties at elevated temperatures. On pyrolysis, the TSTR cross-linked polyimides were converted to refractory type materials which are believed to be graphitic type ladder polymers containing some nitrogen in their cyclic structures. 

The polyimide class of polymers are known to possess a high degree of thermal stability. They decompose in an inert atmosphere around 500°C and in air about 400°C as indicated by thermo-gravimetric analysis (1). Because of the great thermal stability of 2,4,6-triphenyltriazine (2J (decomposes above 486°C), copolymerization of this compound with imides should lead to enhanced heat resistant materials in the form of triaryl-s-triazine ring (TSTR) cross-linked (XL) polyimides. 

Figure 3. Triaryl-s-triazine ring polymer with ring-chain chain structure. Key Q, triazine ring R, NH, etc.

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