Heterogeneous hydrolysis of poly(aryl ether ketimine)s — an alternative synthetic route to semicrystalline poly(aryl ether ketone)s

Abstract

introductionAromatic poly(ether ketone) such as PEEK (3), has gained considerable importance due to its chemical resistance and excellent mechanical and thermal properties. Rose et al. ') were first to succeed in preparing high-molecular-weight 3, 4,4'-biphenyldiolbased poly(ary1 ether ketone), 4, and related semicrystalline polymers by choosing diphenyl sulfone as the reaction medium at a reaction temperature above 300°C.McGrath et al. *), and later Risse and Sogah3), reported the synthesis of an amorphous high-molecular-weight prepolymer containing removable tert-butyl substituents on the polymer chain. The bulky group could be cleaved to produce semicrystalline poly(ary1 ether ketone)s. Homogeneous hydrolysis of poly(ary1 ether ketimine) with trifluoromethanesulfonic acid was also reported by McGrath et al. ' ). The melting temperature, T,, of the resulting semicrystalline polymer was significantly lower than that of PEEK. The present paper describes a different approach to the hydrolysis of amorphous poly(ary1 ether ketimine)s 1 and 2. The required ketimine-to-ketone transformation was carried out under controlled heterogeneous hydrolysis conditions to afford semicrystalline poly(ary1 ether ketone)s. The polymers were characterized by differential scanning calorimetry (DSC) and the results were compared with the reported thermal transitions of PEEK and 4,4'-biphenyldioLbased poly(ary1 ether ketone) 4. Results and discussionSynthesis of poly(aryI ether ketirnine)s Polymerization of hydroquinone with appropriate ketimine functional difluoride was carried out in presence of potassium carbonate (excess) in N-methyl-2-pyrrolidone/ 0 1991, Hiithig & Wepf Verlag, Basel CCC 0173-2803/91/$01 .OO

Synthesis of novel copoly(ether ether ketones): Property evaluation and microstructure analysis by NMR

“…Many studies have been carried out to improve the low solubility, high T m (i.e., low processability), and low T g of PEEK 3–5, 7–9. Replacement of the 1,4‐phenylene group in PEEK with a 4, 4′‐biphenylene11 group raised the T g . However, the polymer was highly crystalline and has not gained commercial value because of its extremely high T m (395°C).…”

Synthesis and characterization of a novel phthalazinone poly(aryl ether sulfone ketone) with carboxyl group

“…Poly(ether ketone)s (PEK)s and poly(ether sulfone)s (PES)s are the most important high performance engineering thermoplastics, widely used in the electronic, electric, aircraft, and aerospace industries. [1][2][3][4][5][6][7] Initially, considerable effort was made to modify their chemical properties, essentially to improve their thermal properties. 8 In the last few years, more attention has been paid to their functionalization.…”

Synthesis and characterization of soluble copoly(ether ketone)s containing double bonds

“…Copoly(ether ketone)s (PEKs) are a category of important high‐performance engineering plastics known for their excellent thermooxidative, mechanical, electrical, and chemical resistance properties 1–7. These characteristics permit PEKs to be used as insulation, as matrix resins for composite materials, and in electronics applications.…”

“…Copoly(ether ketone)s (PEKs) are a category of important high-performance engineering plastics known for their excellent thermooxidative, mechanical, electrical, and chemical resistance properties. [1][2][3][4][5][6][7] These characteristics permit PEKs to be used as insulation, as matrix resins for composite materials, and in electronics applications. Within this category of high-performance plastics, the best known PEK is poly(ether ether ketone) (PEEK), which was developed by ICI Co. 8 It is a semicrystalline polymer with a glass-transition temperature (T g ) of 144°C and a melting temperature (T m ) of 335°C.…”