Bio-polyamides based on renewable raw materials

Abstract

Structural characterization of a series of novel bio-polyamides based on renewable raw materials - PA 4.10, PA 6.10, PA 10.10, and PA 10.12 - was performed by Fourier transform infrared spectroscopy (FTIR) and wide-angle X-ray diffraction (WAXD). Infrared spectra and the WAXD patterns indicate the coexistence of different crystalline forms, α- and γ-triclinic and β-pseudohexagonal. Thermal properties in the glass transition (T g) and melting region were then investigated using temperature-modulated DSC (TOPEM® DSC). The melting point (T m) was found to increase with increasing amide/methylene ratio in the polymer backbone, which is consistent with the increase in linear density of hydrogen bonds. Studies on the molecular dynamics by dynamic mechanical analysis show three distinct regions associated with the γ- and the β-relaxation and the dynamic glass transition. TOPEM® DSC data reveal that at low frequency/long timescales, the materials with significantly different amide/methylene ratios have similar segmental dynamics.