Bio-sourced flame retardant systems for polymers: the influence of chemical modification of giant reed on thermal stability and flammability of PA11

Abstract

As part of the research, bio-sourced flame retardant systems (FRs) containing raw and chemically modified plants were investigated. This work proposes the combination of melamine phosphate (MP) and giant reed (R) biomass as FRs for bio-based polyamide 11 (PA11). The influence of chemical modification on plant components’ chemical structure was determined using analytical methods. Next, the materials with 20 mass% of the flame retardant systems were obtained by twin-screw extrusion and injection or compression molding, with a fixed MP/R ratio of 3:1. The materials were comprehensively characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and thermal analysis (DSC,TGA). Moreover, research techniques, including pyrolysis combustion flow calorimeter (PCFC) and cone calorimetry, were employed to establish the impact of FRs on the flammability of the polymer. The composition containing NaOH-treated reed showed a reduced heat release capacity, which shifted from 866 J g−1 K−1 for neat PA11 to 580 J g−1 K−1 for PA11/15MP5RN. In turn, the lowest total heat evolved and smoke emission was noted for FRs with reed after boric acid treatment.