The typical procedure for the synthesis of poly(aryl ether ketone) oligomer containing phthalonitrile (PAEK-CN-II) was as following: To a 100 ml, three-necked flask fitted with a thermometer, a Dean-Stark trap with a condenser, and a nitrogen inlet were added DHBP (8.5688 g, 0.04 mol), DFBN (2.7822 g, 0.02 mol), anhydrous [K.sub.2]C[O.sub.3] powder (6.6341 g, 0.048 mol), toluene (7 ml), and NMP (26 ml).
The oligomers labeled as PAEK-CN-I and PAEK-CN-III with different molecular chain length was also obtained by varying the mole ratio of DFBN to DHBP, respectively, according to the similar procedure above.
As shown in Scheme 1, the potassium diphenolate intermediates were first obtained by different excess feed ratios of DHBP to DFBN, and then they were readily converted to cyano-terminated PAEK-CN oligomer, named as PAEK-CN-I, PAEK-CN-II, and PAEK-CN-III with the addition of NPN into the reaction mixture, respectively.
The DHBP was previously diluted in 1, 2, 4 trichlorobenzene (solution at 15%) to have a good precision on the pump flow rate, even for concentrations less than 1000 ppm (i.e.
The injection of DHBP was housed in a unfilled area, just after the melting zone.