Sustainable castor oil-based waterborne polyurethanes (WPUs) are widely applied in multiple fields, while the strategies to simultaneously realize reprocessing, self-healing, and novel applications are attractive and highly demanded. Herein, a molecular design strategy is proposed to incorporate dynamic oxime-carbamate bonds into the castor oil-based WPUs. The obtained networks exhibit excellent toughness (>44 MPa), adequate stretchability, and wonderful self-healing efficiency (>95% at 80 °C for 8 h), which stand out among the reported cases. Moreover, the WPU film retained almost 100% of the original mechanical properties after consecutive reprocessing. With the incorporation of carbon nanotubes, the films are endowed with good electric conductivity, providing a general platform for fabricating flexible electronic devices. Specifically, wonderful performance in trajectory control and collision warning is displayed, which is expected to be an alternative to minimize the utilization of expensive and complex obstacle sensors in automated guided vehicles. This study contributes to the development of sustainable and self-healing WPU-based flexible material and opens the gate for novel and identified applications.
Self-healing is a promising way to solve the difficulty in wind turbine blades repair, yet the embedded healing agent may have a disadvantage because of being exposed to outdoor for a long time. Pressurized delivery of the healing agent in real-time when the blade is damaged may be the solution to avoid the disadvantage healing agent. In this paper, the healing agent was pumped to the damaged area by a peristaltic pump, and the healing effect was evaluated by the recovery rate of the residual flexural strength after impact and the image of ultrasonic C-scan. To evaluate the healing effect of different damage degrees, 10 J, 15 J, 20 J, and 25 J impact energies were applied. The fluid tracer test showed that the healing agent could penetrate in the damaged areas after the impact of 15 J, 20 J and 25 J, while the three-point bending test revealed that the healing efficiency was the highest with 20 J (85.2%). The ultrasonic C-scan and optical photos of the sample showed that the images of the healing area were almost consistent with those of the un-impacted area, indicating that the damaged area is healed well. Based on the success of plate samples, the self-healing of the wind turbine blade-scale prototype was then carried out. Twenty-joule impact was exerted on the blade prototype, and the healing agent was pumped to the damaged area using the peristaltic pump similar to the same procedure as that of the plate specimen. Ultrasonic C-scan and optical images of the damaged area showed that the prototype was healed well in comparison with those of the plate specimens, indicating that the application of pressurized delivery of the healing agent system in the self-healing of wind turbine blade prototype was successful.
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