Calcium carbonate's impact on pine wood flour and talc-filled recycled polypropylene composites for sustainable material applications

Abstract

Incorporating recycled plastics into demanding automotive industry can boost the plastic waste recycling rate. While advancements have been made, challenges remain in enhancing the quality and applicability of recycled plastics. This work aims to develop pine wood flour and calcium carbonate reinforced recycled polypropylene (R-PP)/talc composites using extruder, followed by injection molding. Maleic anhydride modified polypropylene (MAPP) was added to strengthen the bonding of wood flour and (R-PP)/talc. The first step involved extruding wood flour, MAPP, and (R-PP)/talc, then crushing the extrudate into granules. Then the final composites were obtained by injection molding of calcium carbonate and the granulated samples. The properties of hybrid polymer composites were investigated by FTIR spectroscopy, density, mechanical tests (tensile, flexural, izod impact strength), heat deflection temperature (HDT) and Vicat softening temperature (VST). The tensile strength of wood flour and MAPP incorporated samples were improved compared to (R-PP)/talc based control sample and no significant change was observed with CaCO3 addition. The flexural characteristic of all hybrid composites were enhanced, 15 wt% CaCO3 resulted in higher flexural modulus among the composites. However, the elongation at break and impact strength showed decrement for filler incorporated composites. The HDT and VST of hybrid composites increased approximately 10 degrees C and 20 degrees C, respectively, compared to control sample, indicating an enhancement in thermal stability. Overall, the developed hybrid composites can be valuable for the recycling sector. In this context, the evaluation and adoption of recycled polypropylene could pave the way for a more sustainable future, aligning economic interests with environmental stewardship.