PREPARATION AND PROPERTIES OF HIGH MOLAR MASS NYLON-4,6 - A NEW DEVELOPMENT IN NYLON POLYMERS

The preparation, in a two-step process, of poly(tetramethylene adipamide) (nylon-4. 6) has been studied. The first step involves precondensation of tetramethylene-diammonium adipate (nylon-4,6 salt) with water as solvent. A kinetic model is postulated that describes the prepolymerization by a second order amidation reaction with formation of pyrrolidine end-groups as a side reaction. In the second step, prepolymer powder is subjected to solid state polycondensation to achieve a sufficiently high molar mass. High molar mass nylon-4. 6 (Stanyl) exhibits a very high melting temperature (about 290 degree C) and high crystallinity, which makes it an attractive material for applications at high temperature where dimensional stability is a strict demand, such as applications in industrial yarns an engineering plastics.