Flexible Carbon Fiber Composite with Enhanced Durable Impact‐Resistance and Sensing Capability Based on Polyborosiloxane Network

Abstract The demand for lightweight and high‐performance multifunctional composite materials is becoming increasingly widespread nowadays. This study investigates the impact‐resistance and force‐sensing capabilities of polyborosiloxane (PBS) integrated within carbon fiber. Two types of PBS are synthesized with different crosslinking densities, focusing on their rheological and mechanical properties under various strain rates and impact conditions. The results show that peak force is highly correlated with impact energy, rather than velocity, when PBS is in its rubbery state. Interestingly, with the dynamic compression of a high strain rate, PBS produces a yielding stage and then a strengthening stage. Compared to traditional epoxy/carbon laminates, PBS65/Carbon composites exhibited superior impact energy absorption, withstanding up to seven repeated impacts due to the brittle cracking of PBS and its stiffening transition and the self‐healing function. Moreover, the addition of carbon nanotubes to the PBS matrix enabled the development of a force‐sensing composite, which can detect and measure impact forces. The PBS/Carbon laminates also exhibited enhanced flexibility, making them suitable for advanced protective applications requiring repeated impact‐resistance and real‐time force monitoring.