Enhancing Recovery Speed and Anti-Wear Capability of High-Temperature Shape Memory Polymer with Modified Boron Nitride Nanoparticles

Glass transition temperature (Tg) is important for the application of shape memory polymers (SMPs), and here shape memory polyimide (SMPI) with high Tg 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.