German version
Chemicals:
| 1,6-diaminohexane
| | hexane
| | sebacoyl dichloride (decanedioyl dichloride)
| | Na2CO3 · 10 H2O
| | Phenolphthalein 1 % in ethanol (Merck) |
Apparatus and glass wares: |
| crystallizing dish 95 × 55 |
| 2 beakers 150 mL |
| measuring cylinder 100 mL |
| measuring cylinder 10 mL |
| glass stirring rod |
| lab stand, clamp holder |
| winch |
| pair of tweezers |
| plastic gloves |
Hazards and safety precautions:
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4 g of 1,6-diaminohexane are dissolved in 100 ml of aqeous Na2CO3 (5 g of Na2CO3·10 H2O / 100 mL dist. water) in a 150 mL beaker. Five drops of phenolphthalein solution are added. 10 mL of sebacoyl chloride are dissolved in a second beaker containing 100 ml of hexane.
The diaminohexane solution is placed into a crystallizing dish. Afterwards the sebacoyl chloride/hexane mixture is transferred to the dish by slowly pouring the solution down a glass stir rod onto the hexamethylenediamine. A white film of polymer will form immediately between the two immiscible solutions. Phenolphtalein added to the lower aqeous phase enhances the visibility of the interface.
Using a pair of tweezers, the film is grasped and a thread is slowly pulled out from the interface where the two liquids meet. Care must be taken to draw the fiber vertically from the center of the dish. The thread should not touch the sides of the dish. The free end of the string is manipulated onto a winch to wind more and more of the polymer from the dish until one of the reactants is exhausted.
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Discussion:
Nylon 6,10 is formed at the interface between the two solutions. Nylon is the common name for synthetic polyamides. The most generally useful of the polyamides is Nylon 6,6. The designation 6,6 arises from the fact that it is made from six carbon diamine and the
six carbon dicarboxylic acid. The polymer produced in the described demonstration experiment is referred to as Nylon 6,10 because six carbon atoms are from the 1,6-diaminohexane and ten carbon atoms are from the sebacoyl chloride.
The equation is:
Fig. 1: Nylon 6,10
Polycondensation involves the reaction of multi-functional compounds to yield polymers with the release of low-molar-mass by-products.
To undergo a polycondensation reaction the two kinds of monomers must be bifunctional at least. If the monomers react between two mutually immiscible phases as the reaction zone, the reaction is called interfacial polycondensation.
Fig. 2: Nylon 6,6
Disposal: After all the polymer has been collected, wash it thoroughly with water, dry it superficially with a towel, then let it air dry under a laboratory fume hood. The reaction product treated in such a way can be disposed of as 'domestic waste'.
Index of Lecture Experiments
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