1988 Volume 44 Issue 8 Pages 385-393
Single crystal-like nylon 11 were prepared by solid state polycondensation of 11-aminoundecanoic acid (11-AUA) under high pressure. Resultant nylon 11 crystals kept the original shape of 11-aminoundecanoic acid crystals unchanged. Effects of monomer crystallite size, pressure and temperature on the crystallization during the solid state polycondensation were investigated. The crystallization during heterogeneous polycondensation proceeds in “one dimensional and growth” mechanism. Monomers are firstly converted into oligomeric nylon 11 which may be crystallized into pseude hexagonal form. Further chain growth increases crystallite size accompanying crystal transformation to βII-form. Finally, the βII-form crystals transform into the stable α-form crystals.
The smaller monomer crystallite size promotes the reaction rate. Degree of polycondensation depends on the original crystallite size. Increase in polymerization pressure extends polymerizable temperature range and makes the resultant nylon 11 well oriented.
