Synthesis and characterization of poly(arylene ether) containing cyanate ester networks

A series of bisphenols containing ether linkage were prepared from halo phenol/dihalo compound and dihydroxy compounds in the presence of K2CO3. The bisphenols were transformed to cyanate esters by treatment with cyanogen bromide using triethyl amine catalyst. The structure of all the five bisphenols and the cyanate esters were structurally confirmed by FT-IR, H-1-NMR and C-13-NMR spectral methods and elemental analysis. The cyanate esters were cured at 100 degrees C (30 min) -> 150 degrees C (30 min) -> 200 degrees C (60 min) -> 250 degrees C (3 hr). The thermal properties of the cured resins were studied by DSC and TGA. DSC analysis shows that these cyanate esters exhibit T-g in the range of 203-234 degrees C. The CE(c) has the highest glass transition temperature. The cyanate ester CE(e) shows the lowest T-g which is due to its asymmetric structure. The initial degradation temperature of the cured resins was found to be in the range of 324-336 degrees C. The Limiting Oxygen Index (LOI) value, determined by Van Krevelen's equation, is in the range of 35.5-38.7.