Fabrication of Enhanced Epoxy Composite by Embedded Hierarchical Porous Lignocellulosic Foam

Plant biomass exhibits great potential in developing eco-friendly polymer composites. However, their complex composition hinders their utilization in high-performance materials. Herein, rice straw was pretreated by a steam explosion (SERS) and converted into lignocellulosic foam (LCF), which proved to be an efficient enhancement in fabricating epoxy composite. The SERS was dissolved in tetrabutylammonium hydroxide and dimethyl sulphoxide aqueous solution (TBAH/DMSO/H2O) to form a gel, and then freeze-dried to obtain the lignocellulosic foam. By introducing 4 wt% lignocellulosic foam, the compressive strength of the prepared composites (LCF/EP) reached 221.4 MPa, with a density of 1.22 g/cm3. The polarization microscope (POM) combined with a scanning electron microscope (SEM) analysis proved the lignocellulosic foam powder was homogeneously dispersed in the epoxy matrix. The differential scanning calorimetry (DSC) and the structural characterization by infrared spectroscopy (FTIR) show good interaction of straw-based foam with epoxy. The glass transition temperature (Tg) increased to 142.4 °C with 4 wt% content of LCF. The thermogravimetric analysis (TGA) showed an increased onset decomposition temperature of 372.8 °C with the same content of LCF. This work provides a new approach for the development of new lightweight and high-strength composite from biomass polymer.