Potassium fluoride or a mixture of potassium fluoride and iV-neopentyl-4-(dialkylamino)pyridinium chlorides 7,8, or 9 were used as catalysts to improve poly(ether ketone) syntheses of dichloroaryl monomers such as l,4-bis(4-chlorobenzoyl)benzene (1) via nucleophilic displacement. Polymers of increased molecular weight within a significantly reduced reaction time can be obtained by this method, as demonstrated with condensations of 2,2-bis(4-hydroxyphenyl)pentane (4) or 2,2-bis(4-hydroxyphenyl)heptane ( 5) with 1. Furthermore, high molecular weight semicrystalline poly(ether ether ketone)s, commonly known as PEEKK, were synthesized by fluoride anion assisted polycondensation of 1. Under severe conditions, fluoride induced nucleophilic cleavage of the activated ether linkages of the polymers was found.

Polyimides 3a and 3b with stiff-chains bearing trioxaoctyl or tetraoxaundecyl side chains were synthesized and characterized. The polycondensation was done with pyromellitic anhydride and N,N-bis( 1 -imidazolylcarbonyl)-2,5-( 1,4,7-tnoxaoctyl)-or 2,5-(1,4,7,10-tetraoxaundeql)-1 ,Cphenylenediamine (2a or 2b). 3b, being sufficiently soluble, was characterized by I3C NMR spectroscopy. The results of IR and I3C NMR spectroscopy prove the presence of the correct imide structure. In solid state 3a and 3b form layered structures with the side chains being in a disordered state a) Part 6: cf. R. Duran. M. Ballauff, M. Wemel, G. Wegner, MacromolecuIes 21, 2897 (1988). b,

A new synthetic approach to soluble, rigid-rod, aromatic polyimides is described. The polycondensation is done by a Pd-catalyzed aryl-aryl coupling of N,N-bis(4-bromo-2,5-didodecylphenyl)-l,2 : 4,5-pyromellitic diimide (2) and 2,5-didodecyl-l,4-benzenediboronic acid (3). Here, the imide structure is already preformed in monomer 2. A structurally identical polymer is synthesized by the classical procedure condensing 1,2 : 4,5-pyromellitic dianhydride (PMDA) (4) and 4,4"-diamino-2,5,2',5',2",5"-hexadode~l-~-terphenyl(5). Both polymers are characterized in detail by 'H and I3C NMR spectroscopy, membrane osmometry and size exclusion chromatography. The average degree of polycondensation is of the order of 15. The thermal behaviour of the polymers is studied by differential scanning calorimetry and thermogravimetrical analysis.