Poly(ether ketone ether ketone ketone) containing meta|phenylene linkage (PEKEKK(T/I)) was synthesized by electrophilic Friedel|Crafts acylation condensation of 1,4|diphenoxybenzophenone with terephthaloyl chloride (T) and isophthaloyl chloride (I) with a T/I ratio of 1 and characterized by IR、DSC、TGA and WAXD. PEKEKK(T/I) has two different crystal structures: a conventional Form I structure, the same as that observed in PEEK and PEK, wich is usually developed from melt crystallization, and a new Form Ⅱ structure which can be developed from cold crystallization or solvent induced crystallization (by exposing the glassy sample to methylene chloride).
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