Characterization of bio-carbon and ligno-cellulosic fiber reinforced bio-composites with compatibilizer

Bio-composite samples were manufactured using poly (lactic acid) (PLA), high density polyethylene (HDPE), biochar, wood flour, and coupling agent. Biochar, a carbon rich and thermally stable material, derived from switchgrass under controlled pyrolysis was tested as a functional filler. The study aimed at investigating the impact of biochar and wood fiber in the presence of coupling agent (maleic anhydride) on the properties of bio-composites. The bio-composite physical, mechanical and thermal properties were characterized using microscopy, dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), Fourier transform-infrared spectroscopy (FT-IR). The results showed that coupling agent is more compatible with wood flour than biochar. Addition of biochar reduced the moisture absorption and linear thermal expansion of filled bio-composites. It also improved the composites strength and moduli, showing a reinforcing nature of biochar. The TGA thermograms confirmed the improved stability of composites with biochar. Coupling agent was more effective in HDPE matrix reinforced by wood flour than biochar. Overall, this study demonstrated that biochar can be a good filler for improving dimensional stability, mechanical properties, and thermal stability of bio-composites. (C) 2019 Elsevier Ltd. All rights reserved.