Hifza Rouf: Understanding molecular-level interactions within biocomposites

Understanding molecular-level interactions in biocomposite systems is essential for designing sustainable materials with improved compatibility, stability, and mechanical performance. This work presents an integrated framework for analyzing bio-based composite systems by combining solubility theory, thermodynamic modeling, and thermo-mechanical characterization techniques. Hansen Solubility Parameters (HSP) were used to evaluate intermolecular affinity and predict compatibility between polymer matrices, lignin-based fillers, and solvents. The Flory–Huggins interaction model and Gibbs free energy of mixing (ΔGmix) were further employed to investigate miscibility behavior and thermodynamic driving forces governing phase formation and separation within the composites. 

To establish the relationship between molecular interactions and macroscopic material behavior, rheological analysis and Dynamic Mechanical Thermal Analysis (DMTA) were incorporated. Rheometry provided insight into viscoelastic behavior, structural evolution, and interfacial interactions during deformation, while DMTA revealed temperature-dependent transitions, stiffness variations, and damping characteristics of the developed biocomposites. By integrating these multi-scale approaches, the study offers a comprehensive understanding of how molecular compatibility influences phase morphology, processing behavior, and final material performance. 

This framework provides a scientifically grounded strategy for the rational design of advanced bio-based composites and supports the development of sustainable materials with enhanced interfacial properties, thermal stability, and mechanical functionality.