POLYMERIZATION, SPINNIG OF WHOLLY AROMATIC POLYAMIDES AND EVALUATION OF THEIR PROPERTIES

Abstract

With attention to the usage as garments, polymerization, wet spinning and typical properties of three kinds of aromatic polyamides, namely poly-4, 4′-diaminodiphenylmethane-isophthalamide (PAPM-I), poly-3, 3′-diaminodiphenylsulfone-isoph thalamide (MDAS-I), poly-m-phenylneisophthal-amide (MPA-I), were investigated.
By using conventional polymerization process, high molecular weight polymers were obtained for the former two but in the case of MPA-I, the diamine monomer being unstable, meticulous control was necessary to obtain the high molecular weight polymer.
PAPM-I could be spun in water and gave fiber satisfactory with DT 4.8g/d and DE 10%. On the other hand, MDAS-I and MPA-I needed aqueous solution of highly concentrated inorganic salt as coagulant.
These three polymers were self-extinguishing and passed most flammability tests. Generally it is said that light-fastness and dyeability of aromatic polyamides are not acceptable. The relevant results indicated that this is the case with PAPM-I and MPA-I but MDAS-I showed fair improvement though insufficient for the use as garments. The thermal stability could be evaluated by the retention of tenacity and elongation of fibers or by the viscosity of polymers; MPA-I was superior to others. From the facts described above, we conclUded that these polyamides are not suitable to be used in garments and it will be necessary to improve certain properties such as light-fastness and dyeability.