New Method for Fabricating Aromatic Polyamide Particles with a Narrow Particle Size Distribution

Three types of aromatic polyamide particles have been prepared from reacting diamines and diacid chlorides in an acetone or dioxane solution that includes water, using the precipitation polymerization method employing ultrasonic irradiation. The particle diameters were in the range from 300 nm to 1.2 µm with a narrow size distribution. The surface morphology and crystallinity differed greatly among the particles. They began to degrade at temperatures above 400 °C. Also the morphology depended on the ultrasonic frequency. The addition of water was essential to form particles using this polymerization method. Further it was useful to increase the molecular weights of polyamide products.