PROCESS OF PREPARING BROMINATED POLYPHENYLENEOXIDE

The invention relates to a process of preparing the brominated polyphenyleneoxide which can be used for manufacturing the gas separating membranes, ion exchange membranes or as an enzyme fixation carrier and it consists in the reaction of a mixture comprising polyphenyleneoxide dissolved in a mixture of solvents consisting of chloroform and carbon tetrachloride, in a gravimetric ratio of 1 : 3 to 1: 17 and azoisobutyronitrile added at 45 50‹C, in a ratio of 05 2 % as against the amount of brominating agent, N-bromosuccinimide, taken in an amount of 025 1 mole, as against the polyphenyleneoxide structural unit, introduced in portions into the reaction, each said portion being of 1/5 1/3 of the total amount of N-bromosuccinimide, the temperature being increased to 70 76‹C after each portion, maintained at this temperature for 1 3 hours and then the temperature being lowered to 60 65‹C, cooling the reaction mixture, separating thre succinimide, precipitation of the brominated polyphenyleneoxide with a nonsolvent mixture comprising acetone-methanol, the dry polymer having an aliphatic substitution degree of 023 097, an aromatic substitution degree of 001 002 and a bromine content of 144 40 2% Brominated polymers preponderantly in the side chain are obtained, this providing a very important feature for producing the membranes