Rheo-optical Fourier-transform NIR spectroscopy of polyamide 11

Abstract

In order to optimise the end-use properties of semicrystalline polymers such as polyamide 11 (PA 11) in structures of interest for the petroleum industry, the modelisation of their behaviour under mechanical load is a prerequisite. One way to perform this, consists in describing the local material behaviour by using a constitutive stress-strain equation and in calculating the structural behaviour with a finite element model. To evaluate these local deformations on a structural scale simultaneous near-infrared (NIR) spectroscopic and mechanical measurements have been performed in rheo- optical experiments. From the corresponding data, conclusions have been drawn in terms of the orientational behaviour of the polymer in elongation-recovery tests up to 60% strain at 27 °C and 60 °C. Apart from the changes observed as a function of temperature, significant spectroscopic differences could be detected for the absorption bands characteristic of aliphatic sequences and the NH-functionalities, respectively, of the investigated polymer.