Poly bis-l,2,4-triazole s

These polymers have a very good resistance to heat, the decomposition temperatures in general being above 350°C. However, as they are insoluble and infusible, it is impossible to shape the polymers. 

However, materials from poly(bis-l,2,4-triazole)s can be formed by dissolving poly(acyl oxamidrazone)s, e.g., poly(terephthaloyl oxamidraz-one) in dilute aqueous alkah. The solution is then spun or poured into a precipitation bath. The filaments or foils that are formed are washed and heated in an inert gas to a temperature of 240-320°C. 

Pol5miers of 1-vinyl-1,2,4-triazole are nontoxic, have a high hydrophiUc-ity, and a high hydrolysis stabiUty. Possible applications are in the food industry and medicine. Copolymers with of 2-hydroxyethyl methacrylate (HEMA) are used in biological and medical applications. They can be prepared in ethanol and AA -dimethylformamide (DMF) in the presence of 2,2 -azobisisobutyronitrile (AIBN) as the initiator. 

Monomer reactivity ratios with various comonomers are summarized 

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Poly(bis-l,2,4-triazole)s are a class of polymers in which two triazole rings are immediately adjacent. These polymers can be obtained by the reaction of oxalic acid bis-amidrazone with aromatic dicarboxylic acid dihalides or with fumaroyl chloride and subsequent cyclodehydration of the poly(acyl oxamidrazone)s. The process is shown in Figure 9.3. 

Poly(arylene ether triazole)s have also been prepared by heterocyclic-activated displacement polymerization [36], The 1,2,4-triazole unit sufficiently activated, albeit weakly, aryl fluorides for nucleophilic displacement. Several 3,5-bis(4-fluorophenyl)-4-aryl-l,2,4-triazoles were polymerized with various bis-phenols to yield polymers with Tgs from 185 to 230 °C [36]. The 1,2,4-triazole unit appears to be one of the more weakly activating heterocycles towards nucleophilic substitution polymerization. 

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