Yuan Gao, Professor, State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering. Huazhong University of Science and Technology
Traditional manufacturing technologies of thermoset polymer composites based on bulk polymerization requires the usage of autoclaves and ovens supplied with complex temperature and pressure cycle, which results in time-consuming and energy-intensive manufacturing process. Frontal polymerization (FP) involving a self-propagating polymerization front offers a rapid and energy-efficient alternative to manufacture high-performance thermoset polymer and composites. The key features of front velocity and temperature are critical to the efficiency of manufacturing and the material properties of the product, respectively.
Previous efforts have focused on improving front velocity while maintaining a proper range of front temperature by leveraging the reaction-diffusion process of FP, including developing active polymerization reaction, optimizing the chemical composition of the resin, utilizing thermally conductive reinforcing phase, etc. More recent research has revealed the intimate interactions between the polymerization front and the associated fluid field. The presence of fluid fields can impact the front velocity and front shape and can introduce spontaneous patterning, which offers a potential method of morphogenic manufacturing.
In this presentation, I will discuss the numerical and experimental results of FP with fluid fields. I will describe how different types of fluid fields, generated by buoyancy effects, surface tension gradients, and manual introduction, can affect the front velocity and front shape. As for potential application, the fluid fields generated by buoyancy effects and surface tension can trigger instability, leading to spontaneous patterning, which offers a potential method to achieve morphogenic manufacturing; a manually induced fluid field can break the isotropy of front propagation, achieving specific shapes of the cured polymer without the usage of molds.