25.1 Polymers--Condensation Polymerization of Nylon 6,6

Chemical Concepts Demonstrated: Polymerization, condensation polymers


Two solutions are necessary for the demo.
  • Bottom Layer: NaOH dissolved in water, hexamethylenediamine added.
  • Top Layer: Sebacoyl chloride in hexane.

The top layer is carefully poured onto the bottom layer.


    The two layers do not mix.  Nylon 6,6 can be pulled from the interface between the two liquids.

Explanation (including important chemical equations):

    The product of this condensation polymerization reaction is a polyamide.

    n H2N(CH2)xNH2 + n Cl(C=O)(CH2)y(C=O)Cl --> [...(NH(CH2)xNH(C=O)(CH2)y(C=O))n...] + 2n HCl

    It should be noted that this polyamide will continue to form at the liquid interface.  Once the nylon that has already formed is removed, the layers will meet again and more nylon will form.  In fact, if one were to pull slowly enough, quite a bit of nylon could be formed in a single dish.

    Adipoyl chloride can be used instead of sebacoyl chloride.  The commercial process uses adipic acid rather than adipoyl chloride.