Quick analysis of composition of semi-aromatic copolyamide via ¹³C NMR study

Abstract

Standard high resolution ¹³C NMR spectra of PA10T, PA6T, PA106, and PA66 were obtained by a nonacidic solvent mixture of HFIP and CDCl₃. Several chemical shifts were found extremely sensitive to the polyamide type. According to the standard spectra, semi-aromatic copolyamides comprising PA10T, PA6T, PA106, and PA66 units could be distinguished. The ratio of each polyamide component in the copolyamide was determined through the integration of the methylene carbon peak associated with the amine group. ¹³C NMR analysis results were consistent with the theoretical values and copolyamide hydrolysis test results, making ¹³C NMR analysis quite reliable on the quick composition analysis of semi-aromatic copolyamides. Based on this technique, several commercial semi-aromatic copolyamides were further examined and their compositions were easily determined.

Keywords:

• Semi-aromatic polyamide
• composition determination
• ¹³C NMR analysis

Additional information

Funding

This work was supported by the Pearl River Nova Program of Guangzhou under Grant 201610010013; Industry-University-Research Institute Collaborative Innovation Major Project of Guangzhou under Grant 2016201604030023.