CAREER: Extrusion-based Additive Manufacturing of Sustainable Thermoplastics via Enzyme Encapsulation and Microfluidic Structuring of Hierarchical Composites

热塑性塑料的添加剂制造(AM)为消费电子、汽车、航空航天和医疗等行业生产零部件提供了一个巨大且不断增长的市场。随着需求的持续增长，有必要推进AM的科学，以创造工艺和材料，不仅实现性能、效率和成本的平衡，而且特别是解决对环境的影响。该学院早期职业发展(CALEAR)奖支持将可持续塑料复合材料混合物与热保护生物成分和导电填料相结合的新型AM工艺的基础研究。该方法将利用微流控打印技术的创新，使材料能够进行精确的热塑性加工，以结合各种独特的材料特性。一旦完成，该项目将为各种以性能为导向的应用提供材料选择方面的信息，加速可按设计降解的塑料和环境传感器等材料的广泛采用和商业可行性。在其核心努力下，该项目将为各种学生群体建立教育和外联活动，包括那些在这些研究领域历来代表性不足的学生群体。特别是，该项目将为农村高中生和部落大学生开发互动动手三维打印体验，并将可持续、分层聚合物的添加剂制造研究整合到蒙大拿州立大学的课程中。这项跨学科研究的总体目标是使新型多材料热塑性复合材料结构能够结合功能生物，如酶和导电填料。在这一职业生涯中，有两个研究方向。首先是了解制造添加剂制造长丝所需的条件，这些长丝可以成功地包裹热敏性生物衍生的酶成分，从而使它们的生物活性在热塑性加工成最终复合材料时基本保持不变。热屏蔽量将通过分析完整的复合材料样品的环境降解性来量化，这些样品是通过定制设计的用于熔融长丝制造的打印头对材料挤压进行微流控而制造的。第二个重点是探索导电元件的加工和性能，使用所开发的方法来分层构造多材料系统。将利用一种创新的微流控技术，通过设计的AM打印头将材料与精确的局部结构和热控制相结合，以更好地了解所需的工艺条件。此外，将结合实验使用拓扑优化和微流控建模来确定工艺参数空间。这两项研究工作的高潮将是成功地展示一种添加制造的基于生物的被动传感器，该传感器会随着湿度的变化而生物降解。该项目由土木、机械和制造业创新部门(CMMI)和既定的激励竞争研究计划(EPSCoR)共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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) of thermoplastics serves a large and growing market to produce parts for industries such as consumer electronics, automotive, aerospace and medical, etc. As the demand continues to increase, there is a need to advance the science of AM to create processing and materials that not only achieve a balance of performance, efficiency and cost, but especially also address impacts on the environment. This Faculty Early Career Development (CAREER) award supports fundamental research into novel AM processes combining sustainable plastic composite blends with thermally-protected biological components and electrically conductive fillers. The approach will leverage innovations in microfluidic print technologies, which enable precise thermoplastic processing of materials to combine a variety of unique material properties. Once completed, the project will inform materials selection for a variety of performance-driven applications, accelerating widespread adoption and commercial viability of such materials as degradable-by-design plastics and environmental sensors. At its central effort, this project will establish education and outreach activities for a variety of student groups, including those historically underrepresented in these areas of research. In particular, this project will develop interactive hands-on three-dimensional printing experiences for rural high school and tribal college students and integrate additive manufacturing research of sustainable, hierarchical polymers into curricula at Montana State University.The overarching goal of this interdisciplinary research, integrating manufacturing, materials science and chemistry, is to enable novel multi-material thermoplastic composite structures that incorporate functional biologics, such as enzymes, and electrically conductive fillers. There are two research thrusts in this CAREER endeavor. The first is to understand the conditions needed to create additive manufacturing filaments that can successfully encapsulate heat-sensitive biologically derived enzymatic constituents, such that their biological activity is substantially retained upon thermoplastic processing into final composites. The amount of thermal shielding will be quantified by analyzing the environmental degradability of complete composite samples manufactured via microfluidic controls of material extrusions through custom-design print-heads for fused filament fabrications. The second thrust is to explore the processing and properties of electrically-conductive components using the developed methods to hierarchically structure multi-material systems. An innovative microfluidic technique, based on combining materials with precise local structural and thermal control through engineered AM print-heads, will be utilized to better understand the required process conditions. Further, topology optimization and microfluidic modeling will be used in conjunction with experiments to determine processing parameter space. The culmination of these two research efforts will be a successful demonstration of an additively manufactured bio-based passive sensor that biodegrades in response to humidity. This project is jointly funded by the division of Civil, Mechanical and Manufacturing Innovation (CMMI) and the Established Program to Stimulate Competitive Research (EPSCoR).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.