Interfacial Engineering of Lignocellulosics: Manufacturing, Application, and End-of-Life

Increasing awareness of sustainability has directed significant attention towards biobased alternatives to petroleum-based products. Lignocellulosic materials, including cellulose and lignin, an industrial side stream, are valued for their renewability and desired properties. While lignocellulosics are widely used in applications like paper and board, challenges emerge when adapting them for plastic replacements. These challenges include cellulose's tendency to absorb moisture and its incompatibility with hydrophobic polymers, along with lignin's structural variability. This thesis addresses these issues by developing high-performance biobased materials through the strategic assembly of wood building blocks and biodegradable polyesters, like polycaprolactone.  We designed emulsion-based systems by controlling the interfacial interactions between lignocellulosics and other polymers. These colloidal systems served as a foundation for fabricating bioproducts in packaging and thermal insulator foams with competitive properties compared to synthetic alternatives. The developed materials exhibited unprecedented technical performance due to the favourable intercomponent interactions. To gain a comprehensive insight into these interactions, we conducted a detailed analysis of surface-to-bulk interactions in both wet and dry conditions using techniques including quartz crystal microbalance with dissipation, atomic force microscopy, water contact angle measurements, broadband dielectric spectroscopy, and inverse gas chromatography. Beyond these technical advancements, we assessed how these materials degrade in aquatic environments to confirm they break down easily and are environmentally friendly, even if disposed improperly.   Overall, the integration of technological advancements with sustainability assessment across material production and end-of-life scenarios makes this research a holistic package addressing both engineering challenges and environmental imperatives. Hence, it could be of great interest to the forest sector communities and related fields aiming to transform renewable resources into sustainable, high-value material.