Microwave-assisted modification process to enhance the technological properties of maritime pine for sustainable construction applications

Abstract

This research presented a comprehensive investigation of the influence of microwave (MW) treatment on the technological properties of maritime pine (Pinus pinaster) heartwood, including physical, microscopic, chemical, biological, and mechanical performance. Two MW configurations were applied: 400 W and 25 min (MW_400) and 700 W and 5 min (MW_700W). MW_400 treatment significantly improved wood impregnability, enabling 70% higher preservative uptake while maintaining low leaching (4%). The results indicated that MW_400 samples were more stable dimensionally than MW_700, which may be related to the reduction in hemicellulose (12%) and rise in lignin content (22%) of MW_400 samples. The synergistic effect of MW_400 combined with preservative treatment resulted in the highest biological resistance, with reductions in fungal mass loss of up to 54.4%, thereby classifying the wood as resistant. A reduced impact in bending strength (-1% for MW_400 and − 8% for MW_700), modulus of elasticity (-1% for MW_400 and − 4% for MW_700), and compressive strength (-12% for MW_400 and MW_700). MW treatment did not increase the wood’s brittleness. Overall, the MW_400 treatment demonstrated superior performance compared to MW_700, particularly when combined with preservative impregnation, resulting in improvements in dimensional stability and durability while preserving mechanical integrity. Hence, MW-treated wood samples present promising possibilities as construction materials, and MW technology can be a useful, sustainable, and modern methodology for wood treatment.