ON THE FORMATION OF POLY (P-PHENYLENE TEREPHTHALAMIDE) PULPS FROM STIRRED SOLUTIONS

PPTA (poly (p-phenylene terephthalamide)) may precipitate directly from stirred solution by the use of glycerol or glycerol/water coagulant in fibrous pulp form—short fibers with attached fine fibrils that are called PPTA pulp. Scanning electron micrographs show that the precipitated PPTA pulps have a ribbon-like structure similar to Twaron pulps. The wide-angle X-ray diffraction patters of the resultant pulps exhibit three diffraction peaks at 2θ–20.5, 23.5, and 28.5 corresponding to the {110}, {200}, and {004} crystal faces of PPTA fibers, and the peaks are not as sharp as those of fibers. The process yields PPTA pulps with properties such as specific surface areas and mean length depending on the stirring speed, and the ratio of the viscosity of the PPTA/H2SO4 solution to that of the coagulant. The inherent viscosity of the pulps determined by that of the PPTA bulk, which can be easily polycondensated to the desired specification.