Rice husk/glass fiber-reinforced poly(lactic acid) hybrid composites: rheological and dynamic mechanical study

This study explores the effects of incorporating rice husk, glass fiber, and a POE-g-Mah(ethylene–octene copolymer functionalized with maleic anhydride) compatibilizer on the properties of poly(lactic acid) (PLA)-based composites. Through SEM analyses, it is observed that enhanced filler dispersion and interfacial bonding between the PLA matrix and fillers with POE-g-Mah result in improved composite compatibility. The rheological percolation threshold of the rice husk is determined above 30% for the samples containing only PLA and rice husk; however, it is determined between 20 and 30% for the samples containing the POE-g-Mah. The incorporation of POE-g-Mah into the polymer phase causes much higher modulus values compared to its counterparts with the same filler concentration. The DMA results revealed significant enhancements in the modulus of elasticity and damping properties when rice husk and glass fiber were added. The composite with 20% (by weight) rice husk and 5% (by weight) compatibilizer doubled its elastic modulus at 40 °C and increased fivefold to 65 °C with an additional 15% (by weight) glass fiber. This modification substantially reduced energy dissipation and improved damping performance and dimensional stability, which was also evidenced by a decrease in thermal expansion. These findings imply the potential of using rice husk, glass fiber, and POE-g-Mah to significantly enhance the mechanical and thermal properties, offering valuable insights for developing high-performance sustainable materials.

Graphical abstract