Abstract
An analytical method for nylon 6-66 copolymers was investigated with pyrolysis-infrared absorption spectrometry.
The sample weighing 30 mg was pyrolyzed at 500°C under an inert atmosphere (Ar), and the degradation products were trapped in CCl4 cooled to 0°C in an ice-water bath. Then the infrared spectrum of the CCl4 solution was measured on the solution cell. Strong characteristic bands were observed at 2920 cm-1, 1750 cm-1, 1680 cm-1, and were assigned as, νasym (CH) of CH2 groups, ν(C=O) of cyclopentanone and ν(C=O) of ε-caprolactam (Amide I), respectively. Among the absorption ratios between them, A1680cm-1/A2920cm-1 was found to be best with respect to the precision. Determination of the composition of the copolymers was possible by using the calibration curve for the physical blends of the homopolymers. The relative standard deviation was 25%. The pyrolysis mechanism of polyamides was also discussed.
