Collaborative Research: Interfacial Photopolymerization (IPP): A Method For High-Resolution Digital Printing Of Thermoplastics

增材制造（AM）包括许多用于通过逐层方式连续添加材料来生产物体的技术。目前，热塑性聚合物的增材制造技术依赖于局部加热来熔化和重塑材料。通过光聚合形成物体的AM工艺依赖于热固性聚合物的固有交联机制。与热塑性塑料相比，这些光聚合增材制造方法可以生产出具有优越表面光洁度和细节的零件，但这些特性是以牺牲与大规模回收工艺的兼容性为代价的。该奖项将支持首个利用光聚合的可回收热塑性材料增材制造技术的研究，称为界面光聚合（IPP）。这项工作结合了基础材料科学和制造规模，使复杂的数字生产，高分辨率热塑性物体使用市售原料。这项工作将通过在汽车，航空航天，消费和医疗设备行业中使用可回收塑料开辟新的应用，从而具有经济和环境效益，这对我们世界的可持续性做出了重要贡献。在IPP中，聚合过程和分解由LED光源控制，该光源聚焦在位于平面液-液界面或其附近的反应区。这项技术的实现需要对基本的传输和反应动力学、光管理条件和化学热力学进行详细的研究，以阐明聚合物形成的控制物理机制及其在最终打印质量中所起的作用（例如，分辨率、层间附着力、机械性能）。将开发界面扩散和沉淀的宏观动力学模型，以建立对IPP中单层如何形成以及基本限制和参数权衡的定量理解，并将使用定制的基于投影仪的3D打印机来制造演示对象。有关工艺和材料性能的数据将被整合到成本模型中，以比较IPP与增材制造和聚合物注塑方法，并评估IPP在工业规模上的经济可行性。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Additive manufacturing (AM) encompasses many technologies used to produce objects by successive addition of material in a layer-by-layer manner. Currently, AM techniques for thermoplastic polymers rely on local heating to melt and reshape the material. AM processes that form objects by photopolymerization rely on an intrinsic crosslinking mechanism in thermoset polymers. These photopolymerization AM methods can produce parts with superior surface finish and detail relative to the methods available for thermoplastics, but these attributes come at the expense of compatibility with large-scale recycling processes. This award will support research on the first AM technique for recyclable thermoplastic materials that utilizes photopolymerization, called Interfacial Photopolymerization (IPP). This work combines fundamental materials science and manufacturing scale-up to enable the digital production of intricate, high resolution thermoplastic objects using commercially available feedstock materials. This work will have economic and environmental benefits by opening new applications in automotive, aerospace, consumer, and medical device industries that use recyclable plastics, which is a vital contribution to the sustainability of our world. In IPP, the polymerization process and resolution are controlled by a LED light source, which is focused at the reaction zone located at or near a planar liquid-liquid interface. Realization of this technology requires a detailed investigation into fundamental transport and reaction kinetics, light management conditions, and chemical thermodynamics to elucidate the governing physical mechanisms for polymer formation and the role they play in final print quality (e.g., resolution, interlayer adhesion, mechanical properties). A macrokinetic model of the diffusion and precipitation at the interface will be developed to establish quantitative understanding of how single layers form in IPP and the fundamental limits and parameter tradeoffs, and a custom-built projector-based 3D printer will be used to fabricate demonstration objects. Data on process and material performance will be integrated into cost models to compare IPP to AM and injection molding methods for polymer manufacturing and evaluate the economic viability of IPP at industrial scale.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.