Effect of coconut coir and regenerated silk microparticles as blends and natural binders for construction and demolition waste (CDW) wood on the mechanical, thermal, and structural properties of biomicrocomposites prepared by hot-pressing

This study aims to utilize the thermosetting behavior of native lignin and the self-assembly of silk in coconut coir (CC) and regenerated silk (RS) microparticles used as blends and natural binders for construction and demolition waste (CDW) wood and their effect on the mechanical, thermal, and structural properties of CDW wood/CC, RS/CC, and CDW wood/RS biomicrocomposites. The obtained biomicrocomposites were prepared by hot-pressing blended microparticles at weight ratios of 80:20, 60:40, 50:50, 40:60, and 20:80 in the temperature range of 170–180°C. The obtained biomicrocomposites were characterized by bending strength, water resistance, scanning electron microscopy (SEM), thermogravimetric analysis/derivative thermogravimetry (TGA/DTG), and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) measurements. Findings showed that the incorporation of RS displayed superior enhancement in the mechanical properties and water resistance in CDW/RS. The incorporation of CC slightly improved these properties in CDW/CC and RS/CC but offered greater thermal stability, as shown by thermogravimetric analysis (TGA/DTG). The addition of RS and CC showed good interfacial adhesion, as revealed by SEM. FTIR data revealed strong reactivity among CC, RS, and CDW wood.