Method for preparing polyaryletherketone-based copolymer by using quaternary copolymerization technology

A method for preparing polyaryletherketone-based copolymer by using quaternary copolymerization technology comprises: (1) adding high-temperature organic solvent into a three-necked flask equipped with a thermometer, a nitrogen-feeding pipe, and a stirrer; then stirring and heating; orderly adding 4,4′-difluordiphenylketone, 4,4′-bifluorotriphenyldione, hydroquinone, and 4,4′-dihydroxydiphenylketone after the high-temperature organic solvent has been melted, and stirring to completely dissolve them; adding alkali carbonate of 1-5% excessive amount relative to total mole of hydroquinone and 4,4′-dihydroxydiphenylketone; heating to 220-230° C. while stirring, and maintaining the temperature for 20-40 minutes to complete the first salt-forming reaction, (2) heating to 250-260° C., and maintaining the temperature for 20-40 minutes to complete the second salt-forming reaction, (3) heating to 300-320° C. to start condensation polymerization, and maintaining the temperature for 3-4 hours to complete the polymerization, and (4) pouring the obtained polymer solution into distilled water at room temperature to cool to strip-shaped solid, pulverizing, extracting with ethanol to remove organic solvent, extracting with deionized water to remove byproduct salts, and vacuum-drying to obtain quaternary copolymer containing PEEK, PEEKK, PEK, and PEKEKK repeating units in molecule chains. When the mole ratio of hydroquinone to 4,4′-dihydroxydiphenylketone is above 99:1 and the mole ratio of 4,4′-difluorodiphenylketone to 4,4′-bifluorotriphenyldione is above 99:1, the obtained quaternary copolymer mainly contains PEEK chain segments, and has the same macrophysical properties as those of PEEK.