Thermal behavior evaluation of benzoxazine reinforced with macadamiabiomass composites

Abstract

Recently, to improve the properties, reduce the amount of polymeric materials, the time of disposal in landfills and the cost of composite parts, the incorporation of vegetal biomass was considered. In this study, composites with 10% and 20% v/v of benzoxazine resins and macadamia nutshell (50#) were made via hand layup with in natura biomass and hydrothermally treated (121°C/45 min in an autoclave). Thermogravimetry indicates that the initial temperature of biomass degradation (209°C) allows it to be used with the resin (oven curing at 190°C). The enthalpies obtained from the DSC indicate that the percentage of cure increased with the biomass. FT-IR tests indicate that the hydrothermal treatment collapsed part of the lignin and extracted lignocellulosic material. There was no significant modification of the glass transition temperature obtained in DMA and TMA with the introduction of biomass. Optical microscopy showed that the treated reinforcement showed a greater variation in size forming lumps. Based on these results, these composites can be used in the replacement of synthetic composites, contributing to a decrease in the consumption of petroleum derivatives and with this, reducing the disposal in landfills and dumps.