EFFECT OF MOISTURE ON THE BULK PROPERTIES OF SALTED POLY(CAPROAMIDE)

In the reported experiments, the glass-transition temperature (T//g) and the elastic modulus of nylon-6 and its mixtures with 4% w/w LiCl and with 2% LiCl plus 3% LiBr were investigated. In one set of experiments care was taken to avoid absorption of moisture during the measurements. In another set of experiments, samples were exposed to atmospheric humidity for different lengths of time. Both unoriented and oriented specimens were investigated. The presence of 4% LiCl almost doubles the amount of moisture absorbed at equilibrium by nylon-6. The T//g was found to be greatly affected by the moisture content and by salt type. When strict precautions to exclude moisture are taken, the addition of 4% LiCl raises the T//g of nylon-6 by about 25 degree C. The elastic modulus of oriented samples is increased by the addition of salts provided moisture is completely absent. This beneficial effect is, however, completely eliminated when samples are allowed to equilibrate with atmospheric moisture.