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Abstract

Approximately 30% of worldwide greenhouse gas emissions originate from industrial activities, with major contributions coming from the production of steel, concrete, and chemicals (such as plastics). The challenge in decarbonizing these sectors lies in the need for biodegradable and renewable materials obtained from natural biomass which are excellent candidates to replace materials obtained from petrochemicals or through energy-intensive processes (for instance, metal/alloys or concrete). Wood is an environmentally sustainable, benign, and high-performing green structural material readily available in nature which can be used to replace structural materials. However, insufficient mechanical performance, moisture sensitivity, and vulnerability to fire and microorganism attack make it challenging to use the wood as it is in advanced engineering applications. Chemical modification, physical modification and carbonization are some of the ways to enhance the functionality, strength and physical property of the wood. Alkaline pretreatment (delignification) followed by physical densification can transform the low-density wood into a densified wood composite with exceptional strength. Despite efforts for many years, mass commercialization of either bulk or surface-densified wood products have not yet been achieved. Because traditional densification methods are time-consuming, energy-intensive, and requires post-treatment to meet end requirements. This thesis is focused on understanding the use of benign chemical as polylactic acid, colloidal silica and use of deep eutectic solvent to chemically modify the wood during densification process. This proposed project will test the hypothesis that physical densification combined with chemical modification will reduce the densification time and energy and impart not just high mechanical performance but also the functionality (water repellency, flame retardant, surface hardness) based on the chemical modifier used. Moreover, to take one step further, we also showcased the ability of utilizing wood for non-structural applications for electromagnetic interference shielding by combining iron salt with the carbonization technique. In conclusion, the research proposed in this thesis has tried to address the research gaps in the densification domain to make it an industrially viable process and to highlight wood’s ability not just for structural but also for advanced application for electromagnetic shielding.