HYDROGEN-BONDING EFFECTS IN GLASSY STATE OF RANDOM COPOLYAMIDES

The thermal behavior of random copolyamides which are used as model polymers with hydrogen bonds has been investigated by differential scanning calorimetry (DSC), x-ray diffraction, and IR spectroscopy. The quenched copolyamides have only halo patterns in their x-ray diffraction photographs. When the sample was kept at the glass transition temperature (20C), no change in x-ray diffraction was observed after the treatment. The free amide band in the infrared spectrum at 3450 cm**-**1, however, was decreased in intensity by keeping the sample at the glass transition temperature. The transition peak height observed in a DSC curve also increased in the same experiment. It is concluded that in the case of the random copolyamide, structures corresponding to a given enthalpy of the glassy state can be related to the number of hydrogen bonds.