Question

Write the mechanism of the polymerization between 1,6-hexane diacid chloride and 1,2-ethylenediamine (show all steps and arrows).

How will the structure of the polymer change if you used the monomer ?-aminobutyryl chloride?

How do you calculate the yield for a polymer?

Answer 1

The adoption of definite chemical structures for polymers has had farreaching practical applications, because it has led to an understanding of how and why the physical and chemical properties of polymers change with the nature of the monomers from which they are synthesized. This means that to a very considerable degree the properties of a polymer can be tailored to particular practical applications. Much of the emphasis in this chapter will be on how the properties of polymers can be related to their structures. This is appropriate because we already have given considerable attention in previous chapters to methods of synthesis of monomers and polymers, as well as to the mechanisms of polymerization reactions. The special technical importance of polymers can be judged by the fact that half of the professional organic chemists employed by industry in the United States are engaged in research or development related to polymers.

The inclusion properties of cyclodextrins, namely, complex-formation between a guest molecule and a cyclodextrin molecule, have been extensively investigated. The complexes, which are formed in the solid state and in solution, consist of guest molecules which are held in the cavity ofthe host cyclodextrin and are stabilized by Van der Waals forces, and, to a lesser extent, by dipole-dipole interactions. Inclusion complexes in aqueous solutions are thought to be further stabilized by hydrophobic interactions, i.e., by the tendency of solvent water to push hydrophobic solutes of suitable size and shape into the essentially hydrophobic cavity, in order to attain the "most probable structure" of the solvent and obtain minimal energy in the overall system.

Practical use of natural cyclodextrins ( -, ?-, and ?-CDs) as drug carriers is restricted by their low aqueous solubility. Safety is another major concern of cyclodextrins being used as drug carriers due to the toxicity of CD. Modification of the parent cyclodextrin to improve safety while maintaining the ability to form inclusion complexes with various substrates has been the goal of numerous research groups. Some groups have also focused on improving interaction between the pharmaceuticals and the cyclodextrins while others have attempted to prepare materials that can be chemically defined more precisely.

Answer c) Calculate

Hexamethylenediamine = NH2(CH2)6NH2
Molar mass = 116.21
1 g x 1 mol/116.21 g = 0.008605 mol

Sebacoyl chloride = ClCO(CH2)8COCl
Molar mass = 239.14 g/mol
0.5 g x 1 mol/239.14 g = 0.002091 mol

Sebacoyl chloride is the limiting reagent.
0.002091 mol SC x 1 mol Nylon/1 mol SC = 0.002091 mol

Upon reaction, HCl is released, polymeric nylon 6,10 is formed.
Nylon 6,10 = -[NH(CH2)6NHCO(CH2)8CO]-
Molar mass = 282.43 g/mol

0.002091 mol x 282.43 g/mol = 0.59 g