Recycled polypropylene/crystalline cellulose composites obtained using polypropylene functionalized with maleinized hyperbranched polyol polyester as compatibilizing and plasticizing agent.

Highlights Recycled polypropylene (rPP)/crystalline cellulose (rPP/CC) composites are promising alternatives for reducing the detrimental environmental consequences of virgin PP. However, the incompatibility of the rPP/CC composites hinders their widespread application. In this study, PP functionalized with maleinized hyperbranched polyol polyester (PP‐g‐MHBP) was used as a compatibilizing and plasticizing agent for the rPP/CC composites. Furthermore, the effect of PP‐g‐MHBP content on the rheological, thermal, morphological, and mechanical properties of the rPP/CC composites was evaluated. The composites were prepared at a mixing speed of 50 rpm for 7 min and the PP‐g‐MHBP content was varied between 0 and 20 wt%. The torque stabilization time was less than 1 min. The activation energy of flow (Ea$$ {E}_a $$) decreased with increasing PP‐g‐MHBP content, with its values ranging from 0.78 × 102 to 1.42 × 102 kcal.mol−1. The flow index (n$$ n $$) followed the opposite trend with values ranging from 0.55 ± 0.0030 to 0.85 ± 0.0010. PP‐g‐MHBP enhanced the processability, thermal stability and conductivity. The crystallinity, interactions between rPP and CC, and tensile modulus of the rPP/CC composites were also enhanced. Furthermore, it reduced the agglomeration of CC particles. The torque stabilization was lowest for all composites. The composites displayed low activation energy of flow. Recycled polypropylene and crystalline cellulose exhibited good interaction. The plasticizing effect was higher than that of compatibilization. The thermal stability and mechanical properties of the composites improved. [ABSTRACT FROM AUTHOR]