Block structured polyethers based on phenolphthaleine, 4,4'-dichlorodiphenylketone, and bisphenol A with different degrees condensation (n = 1, 5, 10, and 20) were synthesized by means of acceptor-catalytic polycondensation. Equaimolar quantities of chloranhydrides of iso- and terephthalic acids were used. Hgher molecular masses were obtained from longer oligoketones with higher condensation degrees. Better molecular packing, increased thermal and mechanical properties were obtained with higher condensation degrees of of oligoketones. (c) 2007 Wiley Periodicals, Inc.