Enhancing recovery speed and anti-wear capability of high-temperature shape memory polymer with modified boron nitride nanoparticles

Glass transition temperature (T_g) is important for the application of shape memory polymers (SMPs), and here shape memory polyimide (SMPI) with high T_g of 363 °C is reported. High shape recovery speed can improve reliability performance of SMP, and the introduction of modified boron nitride (M-BN) nanoparticles into SMPI matrix can enhance the recovery speed obviously. The faster recovery speed is mainly caused by the increase in thermal diffusivity, which enhances from 0.147 mm² s⁻¹ for primitive SMPI to 0.190 mm² s⁻¹ for the composite with 10% M-BN (SMPI/10% M-BN). Anti-wear capability is important for service life and performance reliability of materials, and wear rate decreases from 7.5 × 10⁻⁹ g N⁻¹ r⁻¹ for primitive SMPI to 0.83 × 10⁻⁹ g N⁻¹ r⁻¹ for SMPI/10% M-BN. The enhanced anti-wear capability is ascribed to high hardness, self-lubricating property and thermal conductivity of BN. Wear mechanism is studied, and it evolves from adhesive and fatigue wear for primitive SMPI to slight adhesive wear for SMPI/10% M-BN.