Renewable Resource-Based Green Composites from Recycled Cellulose Fiber and Poly(3-hydroxybutyrate-<i>co</i>-3-hydroxyvalerate) Bioplastic

TLDR

The study examined how varying recycled cellulose fiber content influences the thermal, mechanical, and dynamic‑mechanical properties of PHBV composites, comparing them to RCF‑reinforced polypropylene. Green composites were fabricated by melt mixing recycled cellulose fibers at 15–40 wt % into PHBV, and their properties were characterized by DSC, TGA, SEM, with tensile modulus modeled using Halpin‑Tsai and Tsai‑Pagano equations. 40 wt % RCF reinforcement raised tensile and storage moduli by 220 % and 190 %, increased HDT from 105 to 131 °C, reduced CLTE by 70 %, and outperformed RCF‑reinforced PP composites in these metrics.

Abstract

Novel "green" composites were successfully fabricated from recycled cellulose fibers (RCF) and a bacterial polyester, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) by melt mixing technique. Various weight contents (15%, 30%, and 40%) of the fibers were incorporated in the PHBV matrix. The effect of the fiber weight contents on the thermal, mechanical, and dynamic−mechanical thermal properties of PHBV was investigated and a comparative property analysis was performed with RCF-reinforced polypropylene (PP) composites. The tensile and storage moduli of the PHBV-based composites were improved by 220% and 190%, respectively, by reinforcement with 40 wt % RCF. Halpin−Tsai and Tsai−Pagano's equations were applied for the theoretical modeling of the tensile modulus of PHBV-based composites. The heat deflection temperature (HDT) of the PHBV-based composites was increased from 105 to 131 °C, while the coefficient of linear thermal expansion (CLTE) value was reduced by 70% upon reinforcement with 40 wt % RCF. The PHBV-based composites had also shown better tensile and storage moduli and lower CLTE values than PP-based composites. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were used to study the melting behavior, thermal stability, and morphology of the composite systems, respectively.