Effect of recycling on polypropylene composites reinforced with glass fibres

Abstract

The aim of the work was to investigate the effect of recycling on the mechanical behaviour of polypropylene composites reinforced with glass fibres (GFs), starting from a material already used in automotive for vehicle components, obtained by injection moulding. Formerly specimens of pristine composites were subjected to tensile and flexural tests, then the specimens were grinded, reprocessed and recycled only once. The recycled composites showed a slight decrease in the elastic modulus and tensile and flexural strength values. Morphological investigations, carried out by scanning electron microscopy and optical microscopy, were also performed to study the microstructure and the fibre–polymer interfaces, together with the GFs’ orientation and distribution within the polymeric matrix before and after the mechanical recycling. The results revealed that the mechanical recycling had no significant effect on the final microstructure and performance of the fully recycled composites, which can be still successfully used for structural applications in the automotive field.

The Influence of Mechanical Recycling on Properties in Injection Molding of Fiber-Reinforced Polypropylene

“…The influence of these individual processes is not determined in this study. However, according to the Colucci et al (2017), the reduction is mainly caused by the mechanical recycling process. After ten consecutive recycling and injection molding steps, the fiber length reduction has even further increased as there is a very high frequency (> 75 %) of small fibers (< 100 µm).…”

“…These studies have shown that the tensile modulus, tensile strength, flexural modulus and flexural strength of the recycled material decrease compared to the virgin material. In contrast, the tensile strain at break and impact strength of the recycled material increase (Bernasconi et al, 2007;Bourmaud and Baley, 2007;Colucci et al, 2017;Giraldi et al, 2004;Kuram et al, 2014;Kuram et al, 2016). During all these experiments, a maximum of five recycling steps were executed.…”

Microstructure, Tensile Property, and Surface Quality of Glass Fiber-Reinforced Polypropylene Parts Molded by Rapid Heat Cycle Molding

“…Short glass fiber-reinforced polypropylene (GFRPP) composites are recyclable materials with good mechanical properties, high chemical resistance, excellent thermal stability, and attractive performance-cost ratio. In view of these advantages, the GFRPP is widely used in structural applications in the fields of aerospace, automotive, civil, and marine engineering [1][2][3][4][5]. It is well known that the macroscopic performance of the product is substantially dependent on its microstructure [6][7][8].…”

Effect of Recycling Cycles on the Mechanical and Damping Properties of Short Alfa Fibre Reinforced Polypropylene Composite

“…However, for the PP/hemp with 30 wt%, these properties vary only by +1.81%, -0.66% and +22.3%, respectively. Moreover, Colucci et al [10] studied the effect of mechanical recycling on glass fibre reinforced polypropylene composite. As a result, they noticed that after one mechanical recycling cycle, their mechanical properties decrease by 8.5%, 23.8% and 27.5% for Young's modulus, tensile strength and flexural strength, respectively, with respect to the values of non-recycled material.…”