Abstract
Polymerization of 12-aminododecanoic acid (12-ADA) to Nylon 12 was carried out by the solid state polycondensation under high pressure. The original crystal shape of the 12-ADA is kept unchanged after the polymerization. In addition, the resultant crystals of Nylon 12 with macroscopic size has single crystal like polymer chain orientation which can be well explained by the “nucleation and growth” mechanism during the polymerisation. The molecular weight is strongly dependent on the pressure, the original monomer crystal size and the defects included in it. The unit cell parameters of γ type crystals of Nylon 12 were determined by x-ray analysis as follows, a=9.14A, b=32.0A, c=4.81A, β=121.0°, and ρc=1.085g/cm3
