Engineering optically recyclable polymer resins for sustainable additive manufacturing

这项研究旨在通过在3d打印材料中引入新的回收机制来提高塑料制造的可持续性。目前，超过30%的3d打印材料在打印后立即被丢弃，这激发了人们对未来3d打印废料在生产时回收的愿景。这项研究将推动从“印刷-填埋”的线性经济向“印刷-回收-重印”的循环经济的转变。为了实现这一转变，提出了3d打印树脂按需再生的新型光学回收技术。基于研究团队的最新发现，该项目结合了可逆光化学和基于纳米技术的光传递机制，以展示3d打印树脂的光学回收。光学可回收树脂通过提供低能耗、按需再生的化学活性聚合物树脂，可以在多次循环中重复使用，有潜力改变塑料加工，超越3D打印。建立光响应聚合物的设计规则将进一步推动半导体、光电子和生物支架材料中大尺寸和高分辨率图案的应用。为了扩大对研究的参与，ppi将从代表性不足的人群中招募和培训研究人员，包括妇女、第一代和低收入（FLI）学生以及代表性不足的少数民族（urm）。研究成果将整合到工程课程中，强调以探究为基础的方法，使学生参与可持续塑料制造的现实挑战。最后，可持续发展和增材制造的概念将通过教育涂色书页面和“无行话”的研究重点进行解释。教育内容将通过网络和旧金山湾区的K-8推广活动向更广泛的公众分发。这项研究的长期目标是通过设计可重复使用的树脂来减少3D打印过程中的塑料浪费，这种树脂可以在多次循环中打印、“擦除”和重新打印。该提案的目标是设计强大的模块化机制，用于光学回收到3D打印的聚合物树脂中。工程树脂包括具有光响应蒽端基（peg -蒽）的多臂聚乙二醇和紫外线发射上转换纳米胶囊。peg -蒽在不同波长的紫外光下发生可逆的光偶联反应；这些反应驱动聚乙二醇-蒽网络的聚合和解聚。发射紫外线的上转换纳米胶囊是由低能量可见光激活的，这种可见光比紫外光更能穿透材料；这些纳米胶囊将提供解聚3d打印材料所需的紫外线。本研究计划的目的1将利用原位动态流变学测量和反应扩散模型量化聚合物结构对光聚合和解聚反应动力学的影响。据推测，由于更快地解聚成更小的组分和更低的溶液粘度，具有更少、更短臂的聚合物将更容易进行光学回收。目标2将确定下转换纳米材料稳定性的化学原理。包封筛选研究将确定核心溶剂和表面配体对紫外发射纳米胶囊稳定的要求。目标3将建立设计规则，以提高光学可回收聚合物树脂的模块化。采用紫色激活的光偶联反应将使下一代树脂易于集成到现代3D打印机中。这项工作将利用pi在聚合物工程、流变学、光学纳米材料和增材制造方面的互补专业知识。这项研究将产生更广泛的影响，包括开发新的聚合物加工和回收技术，在本科和研究生阶段进行研究培训和指导，以及部署有关塑料回收和光学技术的教育和推广内容。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。

This research seeks to improve the sustainability of plastics manufacturing by introducing new recycling mechanisms into 3D-printing materials. Currently, over 30% of 3D-printed materials are discarded immediately after printing, motivating a vision of the future where 3D-printing scraps are recycled at the point of production. This research will drive a transition from a linear economy of “print-to-landfill” to a circular economy of “print–recycle–reprint.” To achieve this transition, novel optical recycling technologies for on-demand regeneration of 3D-printing resins are proposed. Building on recent discoveries by the research team, this project combines reversible photochemistry and nanotechnology based light delivery mechanisms to demonstrate the optical recycling of 3D-printing resins. Optically recyclable resins have potential to transform plastics processing beyond 3D printing by providing low-energy, on-demand options to regenerate chemically active polymer resins that can be reused over numerous cycles. Establishing design rules for photoresponsive polymers will further advance large-format and high-resolution patterning for applications in semiconductors, optoelectronics, and biological scaffold materials. To broaden participation in research, the PIs will recruit and train researchers from underrepresented populations including women, first-generation and low-income (FLI) students, and underrepresented minorities (URMs). Research findings will be integrated into engineering coursework, emphasizing inquiry-based approaches that will engage students in the real-world challenge of sustainable plastics manufacturing. Finally, concepts in sustainability and additive manufacturing will be explained through educational coloring book pages and “no jargon” research highlights. Educational content will be distributed to the broader public online and at K-8 outreach events across the San Francisco Bay Area. The long-term goal of this research is to reduce plastic waste from 3D printing processes by engineering reusable resins that can be printed, “erased,” and re-printed over numerous cycles. The objective of this proposal is to engineer robust, modular mechanisms for optical recycling into polymer resins for 3D printing. Engineered resins comprise multi-arm polyethylene glycol with photoresponsive anthracene end groups (PEG-anthracene) and UV-emitting upconversion nanocapsules. PEG-anthracene undergoes reversible photocoupling reactions in response to different wavelengths of UV light; these reactions drive polymerization and depolymerization of PEG-anthracene networks. UV-emitting upconversion nanocapsules are activated by low-energy visible light that penetrates deeper into materials than UV light; these nanocapsules will deliver UV light needed to depolymerize 3D-printed materials. Aim 1 of this research plan will quantify the influence of polymer structure on photo-polymerization and depolymerization reaction kinetics using in situ dynamic rheology measurements and a reaction-diffusion model. It is hypothesized that polymers with fewer, shorter arms will be more amenable to optical recycling due to faster depolymerization into smaller components and lower solution viscosities. Aim 2 will identify the chemical principles underlying the stability of upconversion nanomaterials. Encapsulation screening studies will determine the core solvent and surface ligand requirements for robust stabilization of UV-emitting nanocapsules. Aim 3 will establish design rules to improve the modularity of optically recyclable polymer resins. The adoption of violet-activated photocoupling reactions will enable facile integration of next-generation resins into modern 3D printers. This work will leverage complementary expertise of the PIs in polymer engineering, rheology, optical nanomaterials, and additive manufacturing. Broader impacts from this research will include the development of new polymer processing and recycling technologies, research training and mentorship at the undergraduate and graduate levels, and deployment of educational and outreach content about plastic recycling and optical technologies.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.