Reversible shape memory polymers (SRMPs) have been identified as having great potential for biomedical applications due to their ability to switch between different shapes responding to stimuli. In this paper, a chitosan/glycerol (CS/GL) film with a reversible shape memory behavior was prepared, and the reversible shape memory effect (SME) and its mechanism were systematically investigated. The film with 40% glycerin/chitosan mass ratio demonstrated the best performance, with 95.7% shape recovery ratio to temporary shape one and 89.4% shape recovery ratio to temporary shape two. Moreover, it shows the capability to undergo four consecutive shape memory cycles. In addition, a new curvature measurement method was used to accurately calculate the shape recovery ratio. The suction and discharge of free water change the binding form of the hydrogen bonds inside the material, which makes a great reversible shape memory impact on the composite film. The incorporation of glycerol can enhance the precision and repeatability of the reversible shape memory effect and shortens the time used during this process. This paper gives a hypothetical premise to the preparation of two-way reversible shape memory polymers.

Nylon 11 is widely used in abrasion-resistant coatings due to its excellent wear resistance and processability. Here, the effects of different processing methods (pre-treatment temperatures, melting temperatures, and heating programs) and nucleating agents (silica, talcum powder, and montmorillonite) on the crystallinity behavior and wear resistance of Nylon 11 were systematically analyzed. The results show that pre-treating Nylon 11 at 80–100 °C enhances its wear resistance, and its friction coefficient drops to ~0.16. Melting temperature influences both the processing flowability and wear resistance of Nylon 11. Specifically, when the melting temperature exceeds 195 °C, wear resistance improves significantly and its friction coefficient decreases from 0.32 to 0.17. Moreover, variations in the heating program also affect the wear resistance of Nylon 11. Optimal wear resistance is achieved when Nylon 11 is held at both 165 °C and 185 °C for 10 min (friction coefficient: ~0.17). The nucleating agents (silica, talcum powder, and montmorillonite) do not change the crystalline morphology of Nylon 11, which predominantly exhibits an orthorhombic α-phase. However, as the content of nucleating agents increases (0–1 wt%), the crystallinity first rises and then declines, with its highest value being 46.48%. This work emphasizes the critical role of processing methods and nucleating agents in the wear resistance and crystallinity behavior of Nylon 11, providing valuable insights for their performance optimization.

Epoxy/dicyandiamide adhesive film is required for the bonding of polymethyl methacrylate (PMMA) aircraft cockpit edges. An imidazole/alkanolamine composite accelerator was developed to satisfy the requirement of maintaining a bonding temperature below 90 °C for this structure, successfully reducing the curing temperature of the adhesive film from 180 °C to 85 °C. The curing process of the low-temperature curing adhesive film and its hydrothermal aging resistance after curing were investigated using mechanical testing, Fourier transform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA). The results indicate that the curing process of 85 °C for 6 h enables the adhesive film to fulfill the adhesion strength requirements for aircraft cockpit edge applications. The cured adhesive film is found to exhibit limited intrinsic water resistance due to its low crosslinking density. Therefore, external edge sealing is required in practical engineering applications to isolate moisture. This work provides an application-specific one-component epoxy/dicyandiamide adhesive film for the low-temperature flexible bonding of aviation PMMA cockpit edges to PETR, and clarifies its adhesion performance and hydrothermal aging behavior under the target service scenario.

Supramolecular polymers, formed through hydrogen bonds and dynamic metal coordination bonds, exhibit excellent reversibility and recyclability. In this study, dimethyl sulfoxide (DMSO) was used as a solvent to synthesize a PTA-AgNO₃-CS (PAC) supramolecular polymer from thioctic acid (TA), silver nitrate (AgNO₃), and chitosan (CS). The non-covalent interactions in PAC enable self-healing and temperature responsiveness. This polymer demonstrates superior mechanical properties, freeze resistance, moisture retention, hemolysis resistance, blood clotting promotion, and antibacterial activity. Capable of 3D printing and repeated fabrication, PAC meets personalized tissue engineering scaffold requirements while reducing production costs. Doped with carbon nanotubes (CNTs), the polymer achieves enhanced conductivity, fatigue resistance, strain sensing sensitivity, and cyclic stability. Field tests using human motion monitoring have confirmed its effectiveness as a reliable strain sensor. Graphical abstract

Supramolecular polymers, formed through hydrogen bonds and dynamic metal coordination bonds, exhibit excellent reversibility and recyclability. In this study, dimethyl sulfoxide (DMSO) was used as a solvent to synthesize a PTA-AgNO ₃ -CS (PAC) supramolecular polymer from thioctic acid (TA), silver nitrate (AgNO ₃ ), and chitosan (CS). The non-covalent interactions in PAC enable self-healing and temperature sensitivity. This polymer demonstrates superior mechanical properties, freeze resistance, moisture retention, hemolysis resistance, blood clotting promotion, and antibacterial activity. Capable of 3D printing and repeated fabrication, PAC meets personalized tissue engineering scaffold requirements while reducing production costs. Doped with carbon nanotubes (CNTs), the polymer achieves enhanced conductivity, fatigue resistance, strain sensing sensitivity, and cyclic stability. Field tests using human motion monitoring have confirmed its effectiveness as a reliable strain sensor.

As space exploration activities and strategic deployments in polar regions continue to advance, higher demands have been placed on the low-temperature resistance of propellant binders. Here, high cis-1,4 content hydroxyl-terminated polybutadiene (HTPB) was successfully synthesized via an oxidative cleavage method using commercial cis-polybutadiene (BR). The microstructure, molecular weight, hydroxyl value, rheological behavior, thermal properties, and mechanical performance of the resulting cis-HTPB were systematically characterized. By adjusting the molar ratio of mCPBA to butadiene units, three cis-HTPB samples with varying molecular weights were obtained. The high cis-1,4 structure (93%) was preserved after modification. The synthesized cis-HTPB exhibited an ultra-low glass transition temperature (Tg) of approximately −100 °C and lower viscosity compared to commercial HTPB, indicating excellent low-temperature flexibility and processability. In addition, the cis-HTPB was further modified with acrylate groups to produce a UV-curable derivative (AcTPB). The cured AcTPB also retained a Tg near −100 °C, demonstrating its suitability for ultra-low-temperature applications and its promise as a photocurable binder for 3D printing propellant.