Recycled PP/EPDM/talc reinforced with bamboo fiber: Assessment of fiber and compatibilizer content on properties using factorial design

Abstract

Thermoplastic composites reinforced with natural fibers have attracted the attention of many researchers, not only for environmental concerns, but also for economic reasons, recyclability, ease of processing, etc. One promising application is in the automotive industry due to their low cost and weight. This industry is increasingly pressured to produce vehicles that consume less fuel and are less polluting. Therefore, plastics reinforced with fibers are required to produce lighter parts to replace the much more abrasive glass fiber and mineral filled composites. One of the most widely used polymers in the automotive sector for manufacturing interior and exterior vehicle components is talc filled EPDM (ethylene-propylene-diene monomer) toughened polypropylene (PP). In this context, the aim of this study was to assess mechanical and thermal properties of bamboo fiber reinforced recycled talc filled PP/EPDM composites compatibilized with maleic anhydride grafted polypropylene (PP-g-MAH). Composites were prepared, according to a 22 factorial design with center point, in a Haake twin screw extruder with subsequent injection molding. Injected specimens were subjected to tensile, flexural, impact and fatigue testing. Morphological analyses were performed by scanning electron microscopy (SEM), and thermal analyses by thermogravimetry (TGA) and differential scanning calorimetry (DSC). Addition of bamboo fiber significantly increased tensile and bending strength, modulus and fatigue life, and decreased elongation at break and impact strength. On the other hand, addition of the compatibilizer had a positive effect only on tensile and flexural strength, and fatigue life whereas the effect was negative on elongation at break and impact strength. The addition of fiber and compatibilizer did not appreciably affect the matrix melting temperature, but slightly increased crystallization temperature and in some cases the degree of crystallinity.