Low‐Loading h‐ <scp>BN</scp> / <scp>TPU</scp> Composites Processed by Thermokinetic Shear Mixing for Injection‐Molded Automotive Applications

ABSTRACT Achieving uniform dispersion and strong interfacial coupling between hexagonal boron nitride (h‐BN) and thermoplastic polyurethane (TPU) remains a key challenge for enhancing composite performance. In this study, low‐loading h‐BN/TPU composites were fabricated using a thermokinetic shear‐mixing process, which facilitated efficient platelet breakup and improved filler–matrix interactions. This scalable approach led to simultaneous improvements across thermal conductivity, mechanical stiffness, and crystallization behavior. The in‐plane thermal conductivity increased from 0.233 to 0.250 W m −1 K −1 at 3 wt.% h‐BN. Notably, the incorporation of h‐BN significantly enhanced the mechanical performance, with the tensile flexural moduli increasing by up to 83.6% and by 35%, respectively, indicating efficient load transfer within the matrix. Furthermore, h‐BN acted as an effective nucleating agent, substantially elevating the crystallization temperature. The resulting modulus values at 2.0–3.0 wt.% loading align with industry specifications for automotive‐grade flexible components, such as sealing elements and protective boots, while maintaining essential elongation capability. A complementary life‐cycle analysis (LCA) confirmed the environmental viability of these composites, with global warming potential (GWP) values remaining below 1.0 kg CO 2 ‐eq per batch. These findings position low‐loading h‐BN/TPU composites as sustainable, high‐performance candidates for lightweight automotive applications.