Study On Synthesis Of Bihalogeneated Triaryl-s-triazine Monomer And Its Poly(Arelene Ether Nitrile)s

Thermal decomposition temperature of triaryl-s-triazine up to 486℃gives polymer containing s-triazine generally excellent thermostability. On the other hand, some polymers containing s-triazine have special photoelectric properties because of the symmetrical structure of triaryl-s-triazine and have potential application in LED. Unfortunately, polyarylether containing s-triazine generally has poor solubility and high softening temperature and can be only processed by melting process. These features limit the application fields of polyarylether containing s-triazine.The synthesis of triaryl-s-triazine is disclosed by literatures and patents in the 60s. The defects of these synthetic methods are low yield and complex product mixture and complicated separation process. In this studing, two kinds of s-triazine monomer were synthesized by the new two-step method.4-Chlorobenzene-l-carboximidamide hydrochloride and 4-flurobenzene-l-carboximidamide hydrochloride via substitutional benzonitile catalyzed by sodium methoxide were prepared. The unreacted nitrile was recycled by recrystalization. The yields of amidine salts can be up to 91.96% and 84.60% respectively.2-Phenyl-4,6-bi (4-chlorophenyl)-1,3,5-triazine (BCPT) and 2-phenyl-4, 6-bi (4-fluorophenyl)-1,3,5-triazine (BFPT) were synthesized by corresponding amidine salts and benzoyl chloride.A series of novel poly(arylene ether nitrile)s were prepared from 4-(4-hydroxyphenyl)-phthlazin-1(2H)-one (DHPZ) and 2,6-difluorobenzonitrile (DFBN) and 2-phenyl-4,6-bi(4-fluorophenyl)-1,3,5-triazine (BFPT) by nucleaphilic displacement polycondensation reaction. The structures of these poly (arylene ether nitrile)s were confirmed by FT-IR and'H NMR. The thermal properties were characterized through DSC, TGA. The resulting PPENPs show high thermal stability with the glass transition temperatures from 300℃to 340℃, and the temperatures for 5% weight loss of the PPENPs were in the range of 510-530℃in nitrogen, the max decomposed temperatures of the PPENPs were in the range of 520-540℃in nitrogen, and the carbon residue rate of the PPENPs were over 60%. The resulting PPENPs have good solubility in some polar solvents and can be cast into thin film with excellent mechanical properties, such as 72-84 MPa of tensile strength,7.6%-11% of elongation at break and 0.98-1.33 GPa of tensile modulus.The PPENPs are amorphous polymers by the characterization of X-ray.