ABSTRACT
The ability of a given solvent or a solvent mixture to dissolve a given nylon can be tested by several procedures. Qualitative tests consist either in observing how long it takes to dissolve a given amount of a sample or in establishing a saturation limit, i.e., the highest reachable concentration. Molecular dissolution of nylons requires such a strong interaction between a solvent and the amide groups that interamidic hydrogen bonds in the polymer would be destroyed. The chains of nylons prepared by the hydrolytic polymerization should have a carboxyl group at one end, and an amine group at the other. The polymers prepared by acidolytic polymerization, i.e., by polymerization with a carboxylic acid as the initiator, have a carboxyl group at one end, and an alkyl group at the other. Viscometry is the simplest and thus the most popular method of molecular characterization of nylons. Turbidimetric titration consists of a precipitation of a polymer from a highly dilute solution.
