Evaluation of mechanical and thermal properties of PP/iron ore tailing composites

This work aims to evaluate the influence of the incorporation of iron ore tailings (IOTs) on the mechanical, thermal, and morphological properties of polypropylene, IOT, and maleic anhydride grafted polypropylene (MAPP) composites. IOTs come in the form of coarse particulates (sand) and fine particulates (iron sludge). Composites were processed using a twin-screw extruder, and specimens for tensile and impact tests were fabricated through injection molding. Results showed that coarse IOTs were predominantly composed of quartz (SiO2) and hematite (Fe2O3), while fine IOTs mainly contained hematite and quartz. Results of the tensile tests showed that, for both types of IOTs, when the IOT content was increased, the modulus of elasticity increased, while the ultimate tensile strength, elongation at break, and impact strength of the composite decreased. Thermal analysis showed that the incorporation of IOTs increased the crystallinity of the composite relative to pure PP; however, the increase in the amount of both coarse and fine IOTs did not significantly change the crystallinity. The melting temperature was influenced by the IOT content for both types of IOTs. The interaction between PP and IOT was not favorable, because PP only partially wetted the IOTs without encapsulating the entirety of the particles. There was a good dispersion of IOT particles into PP; however, there were some formation of agglomerates. In general, both types of IOTs can be used as filler in PP matrix. Therefore, it is necessary to develop a method to improve the interaction between IOTs and PP to successfully manufacture PP-IOT composites.