Continuous Pathway Reinforced Polyurethane-Based Thermal Interface Materials for High-Power Density Chips

Thermal interface materials (TIMs) are indispensable in electronic thermal management, as they mitigate interfacial thermal resistance and improve heat transport efficiency between adjacent components. A major factor hindering the thermal performance of conventional TIMs is the substantial interfacial thermal resistance arising at the interfaces between non-continuous fillers and the polymer matrix. To overcome this limitation, this study develops a continuously oriented TIM using a monolithic pyrolytic graphite film (PGF) combined with film-coating and hot-pressing processes. A polyurethane layer is coated onto PGF films, which are stacked and hot-pressed into a dense composite block. Sectioning the block perpendicular to the pressing direction yields a PGF/PU TIM. The material delivers a thermal conductivity of 118.5 W/(m·K) and demonstrates superior heat dissipation behavior under practical testing conditions. Through the establishment of continuous heat transfer pathways, this strategy alleviates interfacial resistance at filler–matrix interfaces and provides both theoretical basis and technical routes for high-power-density electronic packaging applications.