Modern composite engineering leverages silane coupling agents to integrate nanofillers (CNTs, graphene) with macro-scale reinforcements. By functionalizing carbon fibers with amino-silanes (APTES), researchers achieved 22% increase in interlaminar shear strength in epoxy composites through enhanced matrix-fiber interaction. In hybrid systems, mercapto-silanes create thiol-ene click chemistry bridges between silica nanoparticles and rubber matrices, reducing Payne effect by 35% in tire tread compounds. This boundary-spanning capability enables hierarchical material design from nano to macro scales.