THE ABSORPTION BEHAVIOR AND CRYSTALLIZATION OF POLY(ARYL ETHER KETONE) FILMS

The absorption and subsequent desorption behaviors of amorphous polyme r films of PEEK poly(ether ether ketone), PEEKK poly(ether ether keton e ketone), and PEKK poly(ether ketone ketone) in solvent of 1,2-dichlo roethane (C2H4Cl2) are investigated and compared. The equilibrium abso rption weight (M-infinity) of these polymers is related to their molec ular ketone content or molecular chain rigidity and also to the experi mental conditions. Especially, at a certain temperature, the molecular chains in the solvent can be polarized, which leads to producing grea ter M-infinity for polymer films; for example, at 60 degrees C, M-infi nity = 46% for PEEK and M-infinity = 65% for PEKK. The pseudodiffusion coefficients for PEEK, PEEKK, and PEKK all surpass the 6.0 x 10(-12) m(2) s(-1). The polymer's molecular polarization has been proved in co ncentrated sulfur acid. Results also show that amorphous resin's films become white and creeped in dichloroethane, which is more serious whe n metaphenyl links are introduced into PEEKK or PEKK molecular main ch ains. The residual solvent of 1% or so often exists in the films, even though a long desorption time (over 100 h) has been proceeded. Absorp tion has induced crystallization of amorphous polymer films, but this crystallization process is slightly different from that of the films c rystallized from both the glassy state and the melting state in the so lvent, which makes the amorphous interlayers grow progressively and mo re condensely; thus, the crystallized films will have higher T-g's tha n these crystallized under annealing condition. The morphology results have shown that the solvent-crystallized films are less toughened tha n the amorphous ones because of the intermediate layer between the ind uced crystallized area and the amorphous area in the core. (C) 1998 Jo hn Wiley & Sons, Inc.