FINE POLY(ETHER ETHER KETONE) POWDERS

The physical form of polymers is often important for carrying out subs equent processing operations. For example, fine powders are desirable for molding and sintering compounds because they consolidate to produc e void free components. The objective of this work is to prepare fine polymeric particulates suitable for processing into fiber reinforced p olymer matrix composites. Micron size particles of poly(ether ether ke tone) (PEEK) were prepared by rapidly quenching solutions of these mat erials. PEEK pellets were dissolved at temperatures near the PEEK melt ing point in a mixture of terphenyls and quaterphenyls; then the solut ion was quenched to a temperature between the T-g and T-m (approximate to 225 degrees C) by adding a room temperature eutectic mixture of di phenyl ether and biphenyl. A supersaturated, metastable solution of PE EK resulted, causing rapid nucleation. Fine PEEK particles rapidly cry stallized from this solution. The average particle size was measured u sing transmission electron microscopy, atomic force microscopy, and by light scattering of aqueous suspensions which had been fractionated b y centrifugation. The average particle diameter was about 0.6 mu m. Th ree dimensional photomicrographs obtained via atomic force microscopy showed some aggregates in the suspensions. (C) 1997 John Wiley & Sons, Inc.