Synthesis and properties of polyether ketone and polyether ketone sulfone copolymers

Polyether ketones and polyether ketone sulfone copolymers were prepared by the nucleophilic substitution reaction of 4,4'-difluorobenzophenone with 4,4'-dihydroxybenzophenone and with varying mole proportions of 4,4'-dihydroxybenzophenone and 4,4'-dihydroxydiphenylsulfone using benzophenone/sulfolane solvent mixture in the presence of K2CO3. 4,4'-Difluorobenzophenone was prepared from the reaction of fluorobenzene with carbon tetrachloride in the presence of AlCl3. The polymers were characterized by different physico-chemical techniques. The crystallinity of the polymers was found to decrease with increase in concentration of the dihydroxydiphenylsulfone units in the polymer. Thermogravimetric studies showed that all the polymers were stable up to 460 degrees C with a char yield above 45% at 900 degrees C in N-2 atmosphere. The glass transition temperature of the polymers was found to increase with increase in concentration of the dihydroxydiphenylsulfone units in the polymer. (C) 1998 Elsevier Science Ltd. All rights reserved.