Design and engineering of sustainable biocomposites from ocean-recycled polypropylene-based polyolefins reinforced with almond shell and hull
Rachel Lewis, Haftom Weldekidan, Arturo Rodriguez‐Uribe, Amar K. Mohanty, Deborah F. Mielewski, Manjusri Misra
Abstract
In this work, we discuss the development of a bio-based polypropylene composite by using recycled polypropylene (rPP) and almond shell with hull as green phases. In the first step, a blend of rPP and virgin PP (vPP) was manufactured and evaluated. The melt flow index (MFI) of the blend was higher (∼20 g/10 min) as compared to the neat rPP (∼3 g/10 min). With the introduction of polyethylene-octene elastomer (POE), the impact properties improved dramatically from 29.5 J/m to 203 J/m while the MFI remained close to ∼20 g/10 min which is ideal for injection molding applications. A finely ground almond shell powder was introduced to produce the composites at 20 wt.% filler content. The particle-matrix interface was clearly improved by the addition of 3% maleic anhydride grafted polypropylene (MA-g-PP), as observed in the SEM images. The good particle-matrix interfacial adhesion also improved the tensile and impact strengths by 17% and 15%, respectively. Results obtained in these experiments prove that recycled PP-almond shell reinforced composites show promise for the preparation of alternative new green materials to those manufactured with 100% non-upcycled materials.