Synthesis and Characterization of Isomeric Biphenyl Containing Poly(aryl ether-bisketone)s II. Polymers Derived from 3,3′-(4-Fluorobenzoyl)biphenyl and Bisphenols

Abstract

ABSTRACT:A series of amorphous and semicrystalline poly(aryl ether-bisketone)s have been synthesized from bisphenols and 3,3' -( 4-fluorobenzoyl)biphenyl via nucleophilic aromatic substitution reactions. Model compound studies were carried out with a variety of substituted phenols, 3,3' -( 4-fluorobenzoyl)biphenyl and 3,3' -( 4-chlorobenzoyl)biphenyl. The bishalide monomers were prepared by the reaction of 3,3' -bi phenyl dicarboxylic acid with thionyl chloride followed by Friedel-Crafts reaction with the appropriate aryl halide. Potassium carbonate mediated reaction of these monomers with a variety of bisphenols in dimethylacetamide or diphenylsulfone gave moderate to high molecular weight polymers in excellent yield. The high molecular weight polymers afforded tough films by compression molding. The glass transition temperatures, melting points and the thermal behaviors of the polymers were compared with the corresponding polymers derived from 4,4'-(4-fluorobenzoyl)biphenyl.KEY WORDS Nucleophilic Aromatic Substitution / Glass-Transition Temperatures / Annealing / Poly(aryl ether-ketone)s belong to a class of materials known as engineering thermoplastics.1·2 The introduction of crystallinity into a poly(aryl ether-ketone) backbone results in improving the solvent resistance and modulus. PEEK™, (1, poly(ether ether ketone)) an aromatic poly(ether-ketone) exhibits a relatively high degree of crystallinity and a melting point (Tm) of 335°C. 3 a, 4 , 5 On the other hand, PEEK suffers from poor creep behavior above its relatively low glass transition temperature (Tg) of 145°C. 6 Therefore, attempts have been made to either increase the glass transition temperature or to introduce crosslink sites into the PEEK backbone. 7 -9 The amorphous poly(aryl ether-ketone)s, characterized by backbones containing sp 3 or sp 3 d 2 hybridized atoms (e.g., 2 and 3, respectively), exhibit lower glass transition temperatures than the analogous amorphous poly(aryl ether-sulfone)s, 4 and 5. 10 · 11 In order to achieve higher Tgs and/or higher Tms, two carbonyl groups, (in contrast to PEEK which contain one such group) have been incorporated into the polymer repeat unit (e.g., 6a and 6b). 2 • 12 -15 Polymer 6a was synthesized by the reaction of bisphenol-A with either 7a or 7b via nucleophilic aromatic substitution reactions. Electrophilic aromatic substitution reactions have been used also for the synthesis of poly(aryl ether-ketone)s (e.g., Sa and Sb) containing two keto substituents. 16 • 17

Poly(aryl ether ketone)s containing dibenzoylbiphenyl groups: dynamic mechanical and physical ageing behaviour

“…Other modi®cations to aromatic poly(ether)s and poly(ether ketone)s have aimed at increasing the glass transition temperature while retaining other desirable properties, through the incorporation of dibenzoylbenzene and dibenzoylbiphenyl (DBBP) groups. 6,7 We report here the investigation of the dynamic mechanical and physical ageing behaviour of series of amorphous poly(aryl ether ketone)s containing 2,2'-DBBP and 3,3'-DBBP groups and a range of connecting units, to gain an insight into the effect of chemical structure and substitution pattern on relaxation behaviour.…”