Study on the Melt Memory Effect and Melt Recrystallization Behavior of Crystallizable Biphenylene Poly(arylene ether sulfone ketone)

Abstract

Poly(arylene ether sulfone) resins are usually a class of amorphous polymers, which makes them inferior to other semicrystalline aromatic polymers in solvent resistance, chemical stability, and mechanical strength. Herein, a crystallizable poly(arylene ether sulfone ketone) with a high biphenylene content (BD-PESK) was designed and synthesized. BD-PESK showed excellent thermal stability with a Tg of 241 °C and 5% weight loss temperature of 548 °C. Meanwhile, BD-PESK exhibited an obvious melt memory effect at 350–370 °C, but a weak melt memory effect would survive even above its equilibrium melting point due to the high segment rigidity. Under the guidance of this effect, the melt recrystallization of BD-PESK with a maximum crystallinity of 23% can be realized effectively, which made it have excellent solvent resistance similar to the PEEK resin. Semicrystalline BD-PESK showed a high tensile strength up to 86 MPa with a good elongation at break of 23%. Furthermore, due to the combination of high Tg and semicrystallinity, BD-PESK could maintain 71% storage modulus at 240 °C and still 1.4% storage modulus at 300 °C, respectively, showing superior heat resistance to most thermoplastic polymers.