Polypropylene homopolymer/unmodified minor mineral fuller’s earth composites: a comprehensive experimental study on mechanical and thermal properties

This paper provides a thorough investigation of the mechanical, thermal and morphological properties of polypropylene homopolymer (HPP) reinforced with unmodified minor mineral fuller’s earth (UMMFE) to comprehend and evaluate the properties over conventional polypropylene. UMMFE was characterised by FTIR, TGA, SEM and particle size analysis. HPP/UMMFE composites were prepared on a co-rotating twin-screw extruder with a varied content ranging from 0 to 5% (by weight). The dispersibility of HPP and UMMFE was analyzed using scanning electron microscopy (SEM). Mechanical tests showed an increment of 14% in the tensile modulus for HPP5, in which UMMFE demonstrated a strong reinforcing effect to sustain stress, also resulting in improved tensile strength-at-yield by 13%. Also the flexural modulus increased, showing a 28% rise from 1652 MPa (HPP) to 2122 MPa (HPP5). It was found that UMMFE particles in the HPP matrix affected the interfacial properties of the composites. The comparative investigation of thermogravimetric analysis (TGA) also revealed that the thermal stability of the composites reinforced with UMMFE at 5% (by weight) increased by approximately 56.37%. HPP/UMMFE composites exhibited optimum performance at 5% (by weight) clay loading. This study aims to use UMMFE clay as a potential filler in various sectors of application like automobile, manufacturing, construction, packaging and act as a cushion in the scenario of scarcity of material.