A study of water dehydration in nylon 6 as a function of temperature using two-dimensional (2D) correlation near-infrared (NIR) analysis

The dehydration progress of nylon 6 was investigated at two different temperatures, using near-infrared (NIR) spectroscopy. The two-dimensional (2D) correlation technique was applied to analyse the experimental data. In the region of the O–H combination band (5350–5000 cm−1), the asynchronous spectra of the two temperatures resolve the complex band into three component bands centered at 5280, 5230, and 5140 cm−1, respectively, indicating the existence of three species of water molecules in different states of hydrogen bonding. From the study of the 2D correlation analysis at two temperatures, we have suggested different dehydration mechanisms of the polyamide 6 soaked with water for 50 and 80 °C.