The Coagulating Performance Of Pmia Serum And The Preparation Of Dope-dyed Pmia Fiber

As a variety of Polyamide, Poly (m-phenylene isophthalamide) (PMIA) fiber was first prepared in 1962. Because of its excellent thermal and textile properties, the fiber and paper made from it have been widely used in industrial and clothes applications. After all it plays an irreplaceable role in high temperature resistance area.With the increasing requirement of high temperature resistance fiber, PMIA fiber is fully developed. However, the tight molecular structure and high crystallization of PMIA fiber make it difficult to be dyed, which does harm to the further development of the PMIA fiber.In this paper the influence of impurities in the synthesis of PMIA and the concretionary property of PMIA pulp were studied, the preparation of drop-dyed PMIA fiber was researched too.Firstly, some impurities such as carbinol, ethanol, acetic acid, and ethylamine and so on were added into the system of polymerization respectively. In order to investigate the effect of impurities, the molecular weights of polymer and the lowest contents of various impurities were determined. These are critically for the recycle of solvent in the process of polymeric synthesis and the industrialization of PMIA.Secondly, we choose a model to investigate the pervasion between coagulation bath and fiber. The model can be defined that columniform liquid flow whose diameter was about 1.0cm coagulates. The coagulation bath contains DMAc, water and CaCl₂. Because the proportion of DMAc is higher than the proportion of water, the weight of samples which were coagulated increased with the double-pervasion between DMAc and water. The rate of coagulated can be calculated by the changes of weight. Though there are some bulk effect between the fact and the macroscopical model, this model can reflect the kinetic process of double-pervasion between samples and coagulation bath essentially. We can compare these with the factual rule of coagulation casting during the spinning process and the mechanism of double-pervasion and the influence of process parameter.Finally, the dope-dyed PMIA fibers with different amount of pigment were prepared by wet-spinning. The mechanical properties of the fibers were tested. Infrared spectroscopy, thermogravimetric analysis and sonic orientation were used to study fibers structure and properties. The results showed that the addition of pigment has little effect on the structure and properties of PMIA fibers.The innovation points of this thesis are:1. The influence of impurity in the PMIA polymerization system was analyzed. The effect of varies impurity on the polymerization was discussed, and the minimum content of each impurity that does not affect polymerization and spinning of PMIA in serous was presented. That has some significance to the DMAc recovery course.2. The colored PMIA fibers were obtained with dope-dyed wet spinning method.