Biodegradable date stones filler for enhancing mechanical, dynamic, and flame retardant properties of polyamide-6 biocomposites

The need of using biodegradable fillers as polymer reinforcements instead of the polluting and hazard fillers has recently become a very important issue. Therefore, the aim of this study was the utilization of date stones (DS) as reinforcing and flame retardant biofiller in polyamide-6 (PA6) with and without maleic anhydride-grafted polypropylene (PP-g-MAH) compatibilizer. The composition of DS powder was revealed by X-ray fluorescence (XRF) and chemical methods. Scanning electron microscopy images of biocomposites showed better compatibility of filler/polymer interface at 20 wt% DS and 5 wt% of the compatibilizer. Fourier transform infrared spectroscopy (FTIR) results confirmed our suggested reaction mechanism. The dynamic data showed satisfied enhancement in the storage modulus (E) for maleated PA6 at 20 wt% DS filler. The tensile and impact strengths of the biocomposites enhanced for maleated PA6. The presence of the biofiller had no distinct effect on the thermal stability of the biocomposite. The flame retardant properties significantly improved with increasing DS filler content. The X-ray diffraction and FTIR data revealed that the char layer acted as an insulating barrier to oxygen and heat transfer between the gas phase and the condensed phase thus reduced the heat release rate during the burning. POLYM. COMPOS., 39:1978-1987, 2018. (c) 2016 Society of Plastics Engineers