Aromatic polymers obtained by precipitation polycondensation: 4. Synthesis of poly(ether ketone ketone)s☆
Abstract High molecular weight aromatic poly(ether ketone ketone)s were synthesized by the Friedel-Crafts polyacylation condensation of iso- and terephthaloyl chlorides with diphenyl ether, 1,4- and 1,3-bis(4-phenoxybenzoyl)benzenes. Depending on the monomers used for polycondensation, polyketones of regular structure with different iso-/tereisomer repeating unit ratio ( 100 0 , 50 50 , 0 100 ) in the main chain were obtained. Polymers of each repeating isomer unit were prepared in two different ways. All the polymer syntheses were performed as precipitation polycondensations and the resulting polymers were obtained in particle form. The influence of reaction conditions and preparation route on the polymer properties were examined. The monomer concentration and monomer stoichiometric ratio were found to affect the polymer viscosity. The size and shape of the polyketone particles obtained were also found to be governed by reaction conditions and preparation route.
Synthesis of aromatic poly(ether amide amide ether ketone ketone)s by electrophilic Friedel–Crafts solution polycondensation
A new monomer, N,N′-bis(4-phenoxybenzoyl)-p-phenylenediamine (BPBPPD), was prepared by the condensation of p-phenylenediamine with 4-phenoxybenzoyl chloride in N,N-dimethylacetamide (DMAc). Novel aromatic poly(ether amide amide ether ketone ketone)s (PEAAEKKs) were synthesized by electrophilic Friedel–Crafts solution copolycondensation of BPBPPD with a mixture of terephthaloyl chloride (TPC) and isophthaloyl chloride (IPC), over a wide range of TPC/IPC molar ratios, in the presence of anhydrous aluminum chloride and N-methylpyrrolidone (NMP) in 1,2-dichloroethane (DCE). The influences of reaction conditions on the preparation of polymers were examined. The polymers obtained were characterized by different physico–chemical techniques such as FT-IR, Differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA), and wide angle X-ray diffraction (WAXD). The polymers with 70–100 mol% IPC are semicrystalline and have remarkably increased Tgs over commercially available poly(ether ether ketone) (PEEK) and poly(ether ketone ketone) (PEKK) due to the incorporation of amide groups in the main chain. The polymers with 70–80 mol% IPC had not only high Tgs of 209–213°C, but also moderate Tms of 339–348°C, which are suitable for melt processing. The polymers with 70–80 mol% IPC had tensile strengths of 107.5–109.8 MPa, Young's moduli of 2.53–2.69 GPa, and elongations at break of 9–11% and exhibited high thermal stability and good resistance to organic solvents. Copyright © 2009 John Wiley & Sons, Ltd.
Effects of molecular weight on selected physical properties of polyaromatic ether-ketones
Polyaromatic ether-ketones with various inherent viscosities were prepared and their thermal properties and stress–strain relationships were studied. It was found that the polymer should have an inherent viscosity greater than 0.8 in order to give flexible films, but there was no difference in thermal and stress–strain properties among polymers with viscosities greater than 0.8. Values of 110 MPa and 13% are considered to be the standard values of tensile strength and elongation, respectively, for these polyaromatic ether-ketones. The crosslinking effects on these properties were also studied, using polymers containing 1 and 5 mol % of crosslinkable biphenylene units, but no significant changes in the properties due to crosslinking were observed.