Surface modifications of natural fibers and synthesis of inorganic nanoparticles for tailoring of the interphase and the flame retardancy of green composites

This thesis wants to show some applications which exploit sol-gel methodologies and its advantages to solve industrial and technological problems inherent the use of polymer based bio-composites. These composites can show severe limitations due to the easy flammability of the polymer matrix; this behavior can significantly restrict the application fields of these materials, especially when the possibility of the use of the composites is strictly related to specific regulatory fire tests that have to be passed, hence ensuring public safety (e.g., in the aerospace industry). Additional limitations descend from the mechanical properties of the above mentioned bio-composites, which may be due to a low interfacial adhesion between the filler (e.g., natural fibers) and the polymer matrix. Sol-gel methodologies can improve the fire behavior and the mechanical properties of bio-composites through the in-situ synthesis of ceramic domains in the polymer network and the tailoring of the interphase between filler and matrix.