AROMATIC POLYMERS OBTAINED BY PRECIPITATION POLYCONDENSATION .6. MORPHOLOGY OF POLYKETONE PARTICLES

Syntheses of aromatic polyketones in the form of particles were perfor med using a very small monomer concentration (0.05 mol/l) by the preci pitation polycondensation method. Some of these particles present high ly ordered elongated needle-like structures (whiskers) particularly fo r the all-para polyketone samples. The use of isophthaloyl instead of terephthaloyl for the same low monomer concentration produces, in addi tion to the globular particles, bundles of ribbon-like structures. The average size of the needle-like particles is 1-5 mu m in width and 15 0-250 mu m in length. The factors controlling the morphology texture a nd size of the whiskers and ribbons are shown to be the polymer struct ure and the reaction conditions. Formation mechanisms are discussed.