Improved monomer synthesis for poly(arylene-ether-ketone-imide)

POLY 191

David H. Wang, david.wang@wpafb.af.mil1, Timothy Marsh, timothy.marsh@case.edu2, Patrick T. Mather, patrick.mather@case.edu2, and Loon Seng Tan, Loon-Seng.Tan@wpafb.af.mil3. (1) University of Dayton Research Institute, Dayton, OH 45469, (2) Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, 44106, (3) Polymer Branch, AFRL/MLBP, U.S. Air Force Research Laboratory, 2941 Hobson Way, Ste 136, Wright-Patterson AFB, OH 45433-7750
Previously, we prepared a hyperbranched poly(arylene-ether-ketone-imide) (PAEKI) and functionalized with thermally reactive groups such as propargyl, allyl, epoxy, phenylethynyl, acetylene and phthalonitrile groups at its chain ends (Polym. Prepr., 2006, 47(1), 298). A small amount of allyl-terminated PAEKI promoted a remarkable 65-fold decrease in melt viscosity and some property improvements in a bisphenol-A-based maleimide (BPA-BMI) resin (Polymer 2006, 47, 2813). However, the respective AB 2 monomer, N-[3,5-bis(4-hydroxybenzoyl)benzene]-4-fluorophthalimide, was originally synthesized via a five-step sequence. From an economic standpoint, it would be attractive to improve the yield of each step, shorten the synthetic route or both for future scale-up. Therefore, we have shortened the synthetic route by reducing the total number of steps from five to four. This was accomplished by using methanesulfonic acid (MSA)/P2O5 as a Friedel-Crafts reaction medium, obviating the need for a bis(acid chloride) intermediate. A core molecule was also synthesized from the key intermediate, 3,5-bis(4-hydroxybenzoyl)aminobenzene, and 2,2-bis(phthalic anhydride)-1,1,1,3,3,3-hexafluoroisopropane. It co-reacted with the AB 2 monomer during the self-polymerization, and one-pot-functionalization with propargyl groups allowed HT-PAEKI to be easily characterized with thermal analysis.