Phosphorylated avocado seed: A renewable biomaterial for preparing a flame retardant biofiller

Abstract

Avocado seed was first washed, dehydrated, and pulverized, and thereafter, chemically modified with phosphoric acid in the presence of urea, to obtain a low density and sustainable fire retarding filler. Infrared spectroscopy, nuclear magnetic resonance, and X-Ray photoelectron spectroscopy were used in order to determine the resulting chemical structure and confirm the presence of the proposed functional groups. In addition, scanning electron microscopy and elemental analysis were used to establish the resulting morphological changes, as well as the elements present on the modified material. Thermogravimetric analysis was also carried out in order to establish the thermal stability of the material and predict the effect on the flame retardancy due to the mentioned chemical modification. It was also determined that chemical modification greatly increased the thermal stability of the avocado seed.The flame-retardant effect of the modified avocado seed was assessed in polyethylene/ethylene-vinyl-acetate (PE/EVA) composites via cone calorimeter tests. It was observed by DSC, that the incorporation of avocado seed, does not affect the melting temperature of the PE/EVA polymer blend. The results showed that the modified avocado seed decreased the peak of the heat release rate (pHRR) by 54% and the total heat released (THR) by 15%. The UL-94 and LOI tests of the modified avocado biocomposites showed an improvement in the flame retardant properties, and reached a UL-94 V-1 classification. Tensile tests showed that the bio-composites with unmodified and modified avocado seed exhibit similar tensile strength and modulus than the LDPE/EVA blend, but a lower elongation. These results suggest that phosphorylated avocado seed could be a good option as a renewable biofiller for polymer composites with enhanced flame-retardant properties.

Assessing the Impact of Sepiolite-Based Bio-Pigment Infused with Indigo Extract on Appearance and Durability of Water-Based White Primer

“…Moreover, the agroindustrial sector generates substantial waste that holds the potential for functional use as cost-effective, high-performance fillers. Within these resources, olive pit powders [20,21], almond shells [22], pistachio nutshells [23], apricot and argan remnants [24], cherry seeds [25], peanut shells [26], avocado seeds [27], and rice husks [28] have been employed to enhance the various properties of polymer matrices. Similarly, numerous studies have examined the impact of bio-based resources as environmentally friendly additives to enhance the hydrophobic characteristics of organic coatings.…”

Functional Olive Pit Powders: The Role of the Bio-Based Filler in Reducing the Water Uptake Phenomena of the Waterborne Paint

“…Finally, the enormous amount of waste generated by the agro-industrial field can be applied as a cost-effective and valuable filler. For example, almond shell [24], pistachio nutshell [11], apricot, argan shell [25], cherry seeds [26], peanut shell [27], avocado seed [28], rice husk, groundnut shell, and coconut shell [29] powders have been studied and employed as fillers for the improvement of the physical and thermal characteristics of polymer matrix composites.…”