Shape memory polymer foam: active deformation, simulation and validation of space environment

Shape memory polymer foam (SMPF) is being studied extensively as potential aerospace materials as they have high compression ratio, high specific strength and high specific modulus compared to other shape memory polymers. In this paper, a composite foam with shape memory epoxy (SMEP) as matrix and polyurethane (PU) as functional phase was prepared. The SMPF has been characterized by different analytical and testing methods, and its chemical crosslinking reaction and material properties have been studied. The SMPF was installed in the shape memory polymer composite (SMPC) flexible solar array system (SMPC-FSAS), and ground environment tests and orbital validation were performed. Considering the particularity of space environment, the thermal performance test of ground space environment can effectively test the reliability of shape memory performance. Finally, the SMPC-FSAS carried on SJ-20 satellite successfully deployed on geosynchronous orbit for the first time in the world. Moving forward, SMPF assesses the feasibility of applications in the space field and provides more valuable information.

Design of variable stiffness fixture for computerized embroidery machine based on shape memory polymer

It is a challenge to handle the metal fixture used for cloth clamping in a computerized embroidery machine because of its fixed stiffness. Herein, a prototype that acts as a fixture to provide variable stiffness property is explored by discussing the potential of a thermal-sensitive epoxy resin-based shape memory polymer (SMP). The general model of fixture design is obtained after analyzing the working condition of the metal fixture. The structure of the SMP fixture is designed by discussing the material properties and working requirements of SMP, and a theoretical model is established to deduce the relationship between thickness and stiffness of the fixture. Six SMP fixtures that memorized clamping and opening state were manufactured with different proportions of raw materials. The results show that the designed fixtures have a lighter weight but higher clamping force than the metal fixture at room temperature (RT). It is the first work that demonstrates the potential of the SMP fixture to replace the metal fixture in the computerized embroidery machine and provides inspiration for product design with variable stiffness characteristic in engineering.

Development of Trans-1,4-Polyisoprene Shape-Memory Polymer Composites Reinforced with Carbon Nanotubes Modified by Polydopamine

In this study, which was inspired by mussel-biomimetic bonding research, carbon nanotubes (CNTs) were interfacially modified with polydopamine (PDA) to prepare a novel nano-filler (CNTs@PDA). The structure and properties of the CNTs@PDA were studied using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The CNTs and the CNTs@PDA were used as nanofillers and melt-blended into trans-1,4 polyisoprene (TPI) to create shape-memory polymer composites. The thermal stability, mechanical properties, and shape-memory properties of the TPI/CNTs and TPI/CNTs@PDA composites were systematically studied. The results demonstrate that these modifications enhanced the interfacial interaction, thermal stability, and mechanical properties of TPI/CNTs@PDA composites while maintaining shape-memory performance.