Synergistic Toughening of Plywood Using Carbon Fiber and Waste Rubber: An Interpenetrating Polymer Networks Approach

This study investigates the use of carbon fiber (CF) and waste rubber (WR) as reinforcing materials to improve the physical properties of plywood. The impact of key factors—CF content, WR content, and CF length—on mechanical properties such as modulus of rupture (MOR), modulus of elasticity (MOE), and impact strength (IS) is explored. Water absorption (WA) and thickness swelling (TS) are also examined. Seven plywood samples were created by placing CF and WR as the core layer, with a urea-formaldehyde (70 wt.%) and polyurethane (30 wt.%) matrix reinforcing the veneer and core. The results show that CF significantly improves the physical properties at a 99% confidence level. Increasing CF volume and fiber length enhances mechanical properties, with plywood panels exhibiting better performance. The MOR decreased with WR incorporation, but MOE, WA, TS, and IS showed significant improvements, especially when 40 wt.% WR was added, which increased IS by 41.5%. As the comprehensive analysis from the studies, the various set of physical analysis shown the remarkable outcome such as synergistic effect of CF-WR acquires superior performance in engineering wood applications.